CO
Professeur
Scientific activity
Researcher profile
Faculty researcher at the University of Yaoundé I. Grade: Professeur.
Scientific publications
Kedeu Kouvourbe, Christine Claire Waleguele, Yves Martial Mba Nguekeu, Elise Vanessa Ngouadjio Temgoua, Elodie Gaële Matheuda, Marie G. Tsepeupon Matchide and 9 more
Biochemical Systematics and Ecology
Pierre Leonel K. Tafokeu Taguimjeu, Yannick Stéphane Fotsing Fongang, Manon Genva, Lahngong Methodius Shinyuy, Jana Held, Michel Frédérich and 2 more
International Journal of Molecular Sciences
Croton sylvaticus, a tropical African plant, is traditionally used to treat several diseases, including fever, inflammation, and malaria. Essential oils (EOs) from the plant’s leaves, roots, and trunk bark were obtained by hydrodistillation, and their chemical composition was analyzed by gas chromatography–mass spectrometry (GC-MS). The major constituents identified were virdiflorene (18.13 ± 0.46%) in root EO, (E)-β-caryophyllene (18.40 ± 0.60%) in trunk bark EO, and farnesyl acetone (15.26 ± 0.25%) in leaf EO. Notably, Cameroonian C. sylvaticus leaf EO exhibited a distinct and newly described chemotype with high levels of farnesyl acetone, β-copaene-4-α-ol, β-cadinene, α-humulene, and trans-longipinocarveol. In vitro testing revealed significant antiplasmodial activity against Plasmodium falciparum asexual (Pf3D7) and sexual (NF-54 strain) stages, with trunk bark EO showing the highest potency (IC50: 9.06 ± 2.15 µg/mL for Pf3D7 and 0.56 µg/mL for gametocytes). These findings support the traditional antimalarial use of C. sylvaticus and represent the first chemical profile and antiplasmodial efficacy report for its root and trunk bark EOs against both parasite stages. To the best of our knowledge, we also report for the first time the antiplasmodial activity of an EO that exerts significant activity against both the asexual and sexual forms of P. falciparum.
Pierre Leonel K. Tafokeu Taguimjeu, Mariscal Brice Tchatat Tali, Kevine Johane Jumeta Dongmo, Yannick Stéphane Fotsing Fongang, Marie‐Laure Fauconnier, Bruno Ndjakou Lenta and 3 more
South African Journal of Botany
Yves Martial Mba Nguekeu, Herman D. Sonfack Fozeng, Chika I. Chukwuma, Saw Yu Yu Hnin, Nhat Nam Hoang, Emmanuel Mfotie Njoya and 5 more
Journal of Natural Medicines
Yves Martial Mba Nguekeu, Takeshi Kodama, Zin Paing Htoo, Elodie Gaële Matheuda, Marie G. Tsepeupon Matchide, Silvère Augustin Ngouela and 3 more
Chemistry & Biodiversity
Abstract Trichilia dregeana Sond. (Meliaceae) is a plant used in traditional medicine to treat wounds. The anti‐inflammatory potential of the ethyl acetate leaf extract and the presence of euphane‐type triterpenes in this extract have recently been reported by our group. Further investigation of the remaining subfractions of the ethyl acetate fraction afforded a new 19(10→9) abeo ‐euphane‐type triterpenoid ( 1 ), along with six known terpenoids ( 2 – 7 ). The structure of the new compound was elucidated by analyses of the HR‐ESI‐MS, 1D and 2D NMR data and by comparison with previously reported data. We investigated the ability of the compounds to modulate the production of nitric oxide (NO) in LPS‐stimulated RAW264.7 macrophages. The known compounds 3 and 6 exhibited moderate (IC 50 72.06 μM) and mild (IC 50 98.84 μM) inhibitory activities, respectively, without cytotoxic effects on the cells. These results, in conjunction with our previous findings, emphasize the significant role of terpenoid components in the anti‐inflammatory efficacy of T. dregeana leaves and indicate that the rare 3,10‐epoxy‐19(10→9) abeo ‐euphane triterpenoids could serve as a chemotaxonomic marker for T. dregeana .
Brice Maxime Nangmou Nkouayeb, Hermine Laure Maza Djomkam, Georges Bellier Tabekoueng, Willifred Dongmo Tékapi Tsopgni, Gabin Thierry M. Bitchagno, Michel Arnaud Mbock and 6 more
Chemistry & Biodiversity
Abstract The root extract of Nauclea xanthoxylon (A.Chev.) Aubrév. displayed significant 50 % inhibition concentration (IC 50 s) of 0.57 and 1.26 μg/mL against chloroquine resistant and sensitive Plasmodium falciparum ( Pf ) Dd2 and 3D7 strains, respectively. Bio‐guided fractionation led to an ethyl acetate fraction with IC 50 s of 2.68 and 1.85 μg/mL and subsequently, to the new quinovic acid saponin named xanthoxyloside ( 1 ) with IC 50 s of 0.33 and 1.30 μM, respectively against the tested strains. Further compounds obtained from ethyl acetate and hexane fractions were the known clethric acid ( 2 ), ursolic acid ( 3 ), quafrinoic acid ( 4 ), quinovic acid ( 5 ), quinovic acid 3‐ O ‐ β ‐D‐fucopyranoside ( 6 ), oleanolic acid ( 7 ), oleanolic acid 3‐acetate ( 8 ), friedelin ( 9 ), β‐sitosterol ( 10a ), stigmasterol ( 10b ) and stigmasterol 3‐ O‐β‐ D‐glucopyranoside ( 11 ). Their structures were characterised with the aid of comprehensive spectroscopic methods (1 and 2D NMR, Mass). Bio‐assays were performed using nucleic acid gel stain (SYBR green I)‐based fluorescence assay with chloroquine as reference. Extracts and compounds exhibited good selectivity indices (SIs) of >10. Significant antiplasmodial activities measured for the crude extract, the ethyl acetate fraction and xanthoxyloside ( 1 ) from that fraction can justify the use of the root of N. xanthoxylon in ethnomedicine to treat malaria.
Herman D. Sonfack Fozeng, Arno Rusel Donfack Nanfack, Marthe Aimée Tchuente Tchuenmogne, Billy Toussie Tchegnitegni, Marie G. Tsepeupon Matchide, Elodie Gaële Matheuda and 6 more
Biochemical Systematics and Ecology
Hardo Suzy Donfack Chouna, Darline Dize, Donald Ulrich Kenou Kagho, Jean Jules Kezetas Bankeu, Yannick Stéphane Fotsing Fongang, Mariscal Brice Tchatat Tali and 8 more
Parasitology Research
Gaétan Tchangou Tabakam, Takeshi Kodama, Arno Rusel Donfack Nanfack, Yves Martial Mba Nguekeu, Battsengel Nomin-Erdene, Zin Paing Htoo and 5 more
Phytochemistry Letters
Amanda Seumo Seumo, Arno R. Donfack Nanfack, Blanche L. Ndontsa, Gabin Thierry M. Bitchagno, Roukayatou Mbouangouere, Bruno Ndjakou Lenta and 4 more
Natural Product Research
A phytochemical study of the methanol extract of the fruit of Maesa lanceolata resulted in the isolation of a new alkenylbenzoquinone (1), alongside the known compounds (Z)-2,5-dihydroxy-6-methyl-3-(pentadec-10’-enyl)-1,4-benzoquinone (2), 2,5-dihydroxy-6-methyl-3-(nonadec-14’-enyl)-1,4-benzoquinone (3), 2,5-dihydroxy-6-methyl-3-(tridecyl)-1,4-benzoquinone (4), (2S,3S,4R,2’R,9E)-[2’-hydroxytetraeicosanoyl]-2-aminooctadec-9-ene-1,3,4-triol (5), monopalmitin (glyceryl palmitate) (6), lupeol (7), and 3-O-(β-D-glucopyranoside)-β-sitosterol (8). The structures of the compounds were established by the means of spectroscopic (1 D- and 2 D-NMR) and spectrometric techniques (MS). The isolated compounds were assessed for their antibacterial, cytotoxic, and antiradical activities. Compound 2 showed moderate activity against Staphylococcus warneri (DSMZ 20036), while the other compounds were inactive. The two quinones 1 and 2 were significantly cytotoxic, with IC50 values of 0.005 µM and 12.5 µM respectively, and were weakly active towards DPPH radical (IC50 >250 µg/mL).
Flaure Rosette Ehawa Essoung, Brice Mittérant Mba’ning, Alain Tadjong Tcho, S.C. Chhabra, Samira A. Mohamed, Bruno Ndjakou Lenta and 4 more
Natural Product Research
Methanolic extracts of liana of Caesalpinia welwitschiana and leaves of C. bonduc were found to possess moderate antifeedant and ovicidal activities against Tuta absoluta. Bioassay-guided isolation of constituents from the most active fraction of C. welwitschiana led to the identification of four known compounds [isobonducellin 1a and bonducellin 1 b, intricatinol 2, (-)-epigallocatechin-3-O-gallate 4] and one new constituent [welwitschianic acid 3]. The most active fraction of C. bonduc afforded two known constituents neocaesalpin L 5 and neocaesalpin A 6. The isolated structures were elucidated on the basis of their MS, UV, IR and 1 & 2 D NMR spectra and by comparison with literature data. Compounds 2, 4-6 were showed antifeedant and ovicidal properties against T. absoluta, some comparable to that of azadirachtin at 50, 100 and 200 ng/µl. Overall, the present study, conclude that the two species of the plant could be a promising source of eco-friendly botanical constituents.
Brice Mittérant Mba’ning, Joël Eddy Terence Ateba, Angelbert F. Awantu, Luciana da Silva Amaral, Gervais Mouthé Happi, Beate Neumann and 7 more
Trends in Phytochemical Research
One benzophenone, 4′-hydroxy-2,4,6-trimethoxybenzophenone (1) was isolated from the liana and leaves of Salacia nitida (Benth.) N.E.Br., together with n-hexacosane (2), 29-hydroxyfriedelane (3), 3β-friedelinol (4), n-hexacosan-1-ol (5), n-octacosan-1-ol (6), mangiferin (7), β-sitosterol-3-O-β-D-glucopyranoside (8), friedelin (9), 30-hydroxyfriedelin (10), salaspermic acid (11), 22β-epi-maytenfolic acid (12), orthosphenic acid (13), maltose (14), D-mannitol (15), cangoronine (16), 7-hydroxyfriedelane-1,3-dione (17), tingenone (18), pristimerin (19), α-amyrin acetate (20), β-sitosterol (21) and stigmasterol (22), 21-hydroxyfriedelan-3-one (23), abruslactone A (24), and 2α-hydroxypopulnonic acid (25). The structures of the isolated compounds were established by means of spectroscopic analysis. In addition, the structure of (1) was confirmed by its X-ray diffraction. Compounds (1), (7), (10)-(11), (13), (16)-(19) and (25) were evaluated for their antimicrobial activities. Compound (18) showed a significant activity against Staphylococcus aureus (MIC = 23.8 µM) while compounds (11) and (19) exhibited moderate inhibiting effect against Staphylococcus aureus (MIC = 53.8 µM) and Candida glabrata (MIC = 105.9 µM), respectively.
Flaure Rosette Ehawa Essoung, S.C. Chhabra, Brice Mittérant Mba’ning, Samira A. Mohamed, Wilber Lwande, Bruno Ndjakou Lenta and 3 more
Journal of Applied Entomology
Abstract Preliminary screening of extracts of the leaves and stems of four Turraea plant species (Meliaceae) on second instar larvae of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) showed that the methanolic extract of Turraea abyssinica leaves possess good toxic potential with LD 50 of 270.7 ppm. Fractionation of this extract led to isolation of a new limonoid derivative, 12α‐diacetoxywalsuranolide (1) and three other known limonoids [1α,7α,12α‐triacetoxy‐4α‐carbomethoxy‐11β‐hydroxy‐14β,15β‐epoxyhavanensin (2), 11‐epi‐21‐hydroxytoonacilide (3), 11β,12α‐diacetoxycedrelone (4)]. The structures of the compounds were established by IR , UV , mass spectrometry and 1D/2D NMR analyses, and in the case of the known compounds, also by comparison with reported data. All the isolates were tested for their larvicidal activities at different dose range against second instar larvae of T. absoluta . They were found to be more active (with LD 50 < 7.0 ppm) compared to the reference compound azadirachtin ( LD 50 value of 7.8 ppm).
Marthe Tchuente Tchuenmogne, Thierry Ngouana Kammalac, Sebastian Gohlke, Rufin Marie Kouipou Toghueo, Abdulselam Aslan, Müslüm Kuzu and 7 more
Medicines
Background: Pathogenic yeasts resistance to current drugs emphasizes the need for new, safe, and cost-effective drugs. Also, new inhibitors are needed to control the effects of enzymes that are implicated in metabolic dysfunctions such as cancer, obesity, and epilepsy. Methods: The anti-yeast extract from Terminalia mantaly (Combretaceae) was fractionated and the structures of the isolated compounds established by means of spectroscopic analysis and comparison with literature data. Activity was assessed against Candida albicans, C. parapsilosis and C. krusei using the microdilution method, and against four enzymes of metabolic significance: glucose-6-phosphate dehydrogenase, human erythrocyte carbonic anhydrase I and II, and glutathione S-transferase. Results: Seven compounds, 3,3′-di-O-methylellagic acid 4′-O-α-rhamnopyranoside; 3-O-methylellagic acid; arjungenin or 2,3,19,23-tetrahydroxyolean-12-en-28-oïc acid; arjunglucoside or 2,3,19,23-tetrahydroxyolean-12-en-28-oïc acid glucopyranoside; 2α,3α,24-trihydroxyolean-11,13(18)-dien-28-oïc acid; stigmasterol; and stigmasterol 3-O-β-d-glucopyranoside were isolated from the extract. Among those, 3,3′-di-O-methylellagic acid 4′-O-α-rhamnopyranoside, 3-O-methylellagic acid, and arjunglucoside showed anti-yeast activity comparable to that of reference fluconazole with minimal inhibitory concentrations (MIC) below 32 µg/mL. Besides, Arjunglucoside potently inhibited the tested enzymes with 50% inhibitory concentrations (IC50) below 4 µM and inhibitory constant (Ki) <3 µM. Conclusions: The results achieved indicate that further SAR studies will likely identify potent hit derivatives that should subsequently enter the drug development pipeline.
Brice Mittérant Mba’ning, Bruno Lenta Ndjakou, Ferdinand Mouafo Talontsi, Alain Méli Lannang, Birger Dittrich, Silvère Augustin Ngouela and 3 more
The Cambridge Structural Database
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Brice Mittérant Mba’ning, Bruno Lenta Ndjakou, Ferdinand Mouafo Talontsi, Alain Méli Lannang, Birger Dittrich, Silvère Augustin Ngouela and 3 more
The Cambridge Structural Database
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Bruno Ndjakou Lenta, Joél T. Ateba, Jean Rodolphe Chouna, Makoah N. Aminake, Flore Nardella, Gabriele Pradel and 5 more
The Cambridge Structural Database
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Bruno Ndjakou Lenta, Rosine Fotsing Ngamgwe, Louis Kamdem, Jules Ngatchou, Ferdinand Tantangmo, Cyril Antheaume and 4 more
International Research Journal of Pure and Applied Chemistry
International audience
Aimee M. T. Tchuenmogne, Erik V. Donfack, Michel D. T. Kongue, Bruno N. Lenta, Silvère Augustin Ngouela, Etienne Tsamo and 3 more
ChemInform
Yannick Stéphane Fotsing Fongang, Jean Jules Kezetas Bankeu, Muhammad Shaiq Ali, Angelbert F. Awantu, Zeeshan Ahmed, Clement N. Assob and 4 more
Phytochemistry Letters
Brice Mittérant Mba’ning, Bruno Ndjakou Lenta, Didérot Tchamo Noungoué, Cyril Antheaume, Yanick F. Fongang, Silvère Augustin Ngouela and 5 more
Phytochemistry
Eric Vouffo Donfack, Bruno Ndjakou Lenta, Michel D. T. Kongue, Yannick F. Fongang, Silvère Augustin Ngouela, Etienne Tsamo and 2 more
The Cambridge Structural Database
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Emmanuel Jean Teinkela Mbosso, Jules Clément Nguedia Assob, F. Meyer, Bruno Ndjakou Lenta, Silvère Augustin Ngouela, Benjamin Lallemand and 8 more
Phytochemistry
Pierre Watcho, Fabien Zelefack, Silvère Augustin Ngouela, Télesphore Benoît Nguelefack, Pièrre Kamtchouing, Etienne Tsamo and 1 more
Asian Pacific Journal of Tropical Biomedicine
Abstract Objective The aim of the study was to investigate the prosexual activity of two compounds isolated from the hexane extract of the dried roots of Mondia whitei in rats. Methods β–sitosterol and the mixture of α and β–amyrin acetate were isolated and characterised using several reagents, chromatography, mass spectrometry and physical analysis (RMN, 1H and 13C). Sexually inexperienced adult male rats were orally treated with these compounds at doses of 0mg/kg (control), 10mg/kg or 50mg/kg. 1h after the treatment, mount and intromission latencies and frequencies, penile erection, ejaculation latency and post-ejaculatory interval were measured for 60 minutes. Results β–sitosterol and the mixture of α and β–amyrin acetate significantly increased the mount frequency (p 0.05) when compared to control. The two purified compounds were efficient at the lower dose (10 mg/kg b.w) with β–sitosterol being the most potent. Conclusion Results of the present work give added value to the aphrodisiac property of Mondia whitei and further justify its popular use as a sex stimulant.
Angelbert F. Awantu, Bruno Ndjakou Lenta, Tobias Bogner, Yanick F. Fongang, Silvère Augustin Ngouela, Jean Duplex Wansi and 2 more
ChemInform
Abstract isolation, structure elucidation and cytotoxic activity
Angelbert F. Awantu, Bruno Ndjakou Lenta, Tobias Bogner, Yanick F. Fongang, Silvère Augustin Ngouela, Jean Duplex Wansi and 2 more
Zeitschrift für Naturforschung B
Ferdinand Tantangmo, Bruno Ndjakou Lenta, F. Fekam Boyom, Silvère Augustin Ngouela, Marcel Kaiser, Etienne Tsamo and 3 more
Annals of Tropical Medicine and Parasitology
Phytochemical investigation of an ethyl-acetate extract of the stem bark of Markhamia tomentosa (Bignoniaceae), which had good antimalarial activity in vitro, resulted in the isolation of eight known compounds: 2-acetylnaphtho[2,3-b]furan-4,9-dione (1), 2-acetyl-6-methoxynaphtho[2,3-b]furan-4,9-dione (2), oleanolic acid (3), pomolic acid (4), 3-acetylpomolic acid (5), tormentic acid (6), beta-sitosterol (7) and beta-sitosterol-3-O-beta-D-glucopyranoside (8). The structures of these compounds were established by spectroscopic methods. Each of compounds 1, 2, 4 and 5 was evaluated in vitro for its antiprotozoal activities against the ring stages of two chloroquine-resistant strains of Plasmodium falciparum (K1 and W2), the amastigotes of Leishmania donovani, and the bloodstream trypomastigotes of Trypanosoma brucei rhodesiense (the species responsible for human malaria, visceral leishmaniasis and African trypanosomiasis, respectively). Although compounds 1 and 2 exhibited potent antiprotozoal activities, they also showed high toxicity against a mammalian (L-6) cell line.
René F. Soh, Jean K. Bankeu, Bruno N. Lenta, Brice Mittérant Mba’ning, Silvère Augustin Ngouela, Etienne Tsamo and 1 more
Zeitschrift für Naturforschung B
Two new ellagic acid derivatives, named panconosides A (1) andB(2) were isolated from Pancovia pedicellaris together with eleven known compounds (3 - 13). The structures of 1 and 2, as well as those of the known compounds were established by spectroscopic methods and by comparison with previously reported data. Compounds 1 and 2 were tested in vitro for their antibacterial potential against six strains of microorganisms: Micrococcus luteus, Streptococcus ferus, Streptococcus minor, Escherichia coli, Bacillus subtilis, and Pseudomonas agarici. They were found to exhibit moderate antibacterial activity against all the tested strains compared to standard drugs.
Didérot Tchamo Noungoué, Mehdi Chaabi, Silvère Augustin Ngouela, Cyril Antheaume, Fabrice Fekam Boyom, Jiří Gut and 3 more
Zeitschrift für Naturforschung C
A phytochemical study of the stem bark of Vismia laurentii resulted in the isolation of a tetracyclic triterpene, tirucalla-7,24-dien-3-one (1), and seven other known compounds: 3-geranyloxyemodin (2), vismiaquinone A (3), vismiaquinone B (4), bivismiaquinone (5), epifriedelinol (6), betulinic acid (7) and stigmasta-7,22-dien-3-ol (8). The structure of all these compounds was elucidated by spectroscopic means. The stem bark extract and compounds 1 and 3 showed good antimalarial activity against the W2 strain of Plasmodium falciparum.
Bruno Ndjakou Lenta, Krishna Prasad Devkota, Silvère Augustin Ngouela, Fabrice Fekam Boyom, Quamar Naz, M. Iqbal Choudhary and 3 more
Chemical and Pharmaceutical Bulletin
Glaberianthrone (1), a new bianthrone was isolated from the hexane extract of the stem bark of Psorospermum glaberrimum together with thirteen known compounds: 3-geranyloxyemodin anthrone (2), friedelan-3-one (3), 3-prenyloxyemodin anthrone (4), 3-geranyloxyemodin (5), 3-prenyloxyemodin (6), friedelan-3-ol (7), acetylvismione D (8), betulinic acid (9), 2-geranylemodin (10), bianthrone A2b (11), bianthrone 1a (12), emodin (13) and 2-prenylemodin (14). The structures of the isolated compounds were established by means of spectroscopic methods. The extracts and the isolated compounds were tested in vitro for their anti-plasmodial activity against Plasmodium falciparum (chloroquine resistant strain W2) and for their acetyl- and butyrylcholinesterase inhibitory properties. The n-hexane extract showed good anti-plasmodial activity against P. falciparum W2 strain, with IC(50) of 0.87 microg/ml. It also exhibited 65.5% and 98.2% of acetyl- and butyrylcholinesterase inhibition at 0.2 mg/ml, respectively. Compounds 2 and 8 showed the best potencies against P. falciparum W2 strain with IC(50) of 1.68 microM and 0.12 microM, (0.66 microg/ml and 0.054 microg/ml) respectively. All tested compounds showed good butyrylcholinesterase inhibition activities with compound 12 displaying the best potency (IC(50) 9.25+/-0.25 microM). All the tested compounds showed weak inhibitory activity against acetylcholinesterase.
Bruno Ndjakou Lenta, Didérot Tchamo Noungoué, Krishna Prasad Devkota, Patrice A. Fokou, Silvère Augustin Ngouela, Etienne Tsamo and 1 more
Acta Crystallographica Section E Structure Reports Online
The title compound, C 38 H 50 O 6 , also known as guttiferone A, was isolated from the medicinal plant Symphonia globulifera . It is a benzophenone derivative where one aryl group is derivatized to give a bicyclic system which has two prenyl groups attached to the bridgehead. One of the cyclohexane rings in the bicyclic system is in a chair form, while the other has a distorted half-chair conformation. In addition to an intramolecular O—H...O hydrogen bond, intermolecular O—H...O hydrogen bonds link molecules into one-dimensional chains.
Didérot Tchamo Noungoué, Cyril Antheaume, Mehdi Chaabi, Bruno Lenta Ndjakou, Silvère Augustin Ngouela, Annelise Lobstein and 1 more
Phytochemistry
Paul Fewou Moundipa, Silvère Augustin Ngouela, Georges Alain Tchamba, Nico Fréderic Njayou, Pascal Dieudonné Djamen Chuisseu, Fabien Zelefack and 1 more
International Journal of Pharmacology
BL Ndjakou, Bruce G. Weniger, Ferdinand Tantangmo, Mehdi Chaabi, Silvère Augustin Ngouela, Etienne Tsamo and 1 more
Planta Medica
Fourteen extracts from seven Cameroon medicinal plants [1, 2], traditionally used to treat malaria and other parasitic diseases were screened for their antiprotozoal activities against Plasmodium falciparum K1 chloroquine resistant strain and Trypanosoma brucei rhodesiense , protozoa responsible for malaria and trypanosomiasis, respectively. The most active extract against P. falciparum was the methanolic extract of Albizia zygia stembark, with an IC 50 value of 1.04µg/mL. Three of the tested extract showed IC 50 below 7.15µg/mL against T.b. rhodesiense , with Albizia zygia methanolic extract showing again the best activity (IC 50 =0.18µg/mL). These results contribute to the validation of the traditional antiprotozoal use of these medicinal species in Cameroon. References : 1. Vivien J., Flaure J.J. (1973), Arbres des forêts denses d'afrique centrale: Espèces du Cameroun. République Francaise. Agence de coopération culturelle et technique. 2. Laird S.A. et al. (1997), Medicinal Plants of the Limbe Botanic Garden, Cameroon.
Silvère Augustin Ngouela, Bruno Ndjakou Lenta, Didérot Tchamo Noungoué, Joseph Ngoupayo, Fabrice Fekam Boyom, Etienne Tsamo and 3 more
Phytochemistry
Silvère Augustin Ngouela, Fabien Zelefack, Bruno Ndjakou Lenta, Erasmienne Tambou Ngouamegne, Diderot Noungoué Tchamo, Etienne Tsamo and 1 more
Natural Product Research
A xanthone derivative, 3,6,7-trihydroxy-1-methoxyxanthone has been isolated from the stem bark of Allanblackia monticola together with other known compounds, 2,6-dihydroxy-1-methoxyxanthone, allanxanthone A, epicathechin and oleanolic acid acetate. The structure of the new compound was elucidated by spectroscopic methods.
Silvère Augustin Ngouela, Joseph Ngoupayo, Didérot Tchamo Noungoué, Etienne Tsamo, Joseph D. Connolly
Bulletin of the Chemical Society of Ethiopia
A new podocarpane diterpenoid, named gossweilone (1), has been isolated from the stem bark of Drypetes gossweileri, along with two known friedelane triterpenoids. The structure of the new compound was elucidated using spectroscopic methods. KEY WORDS: Gossweilone, Podocarpane diterpenoid, Drypetes gossweileri, Euphorbiaceae Bull. Chem. Soc. Ethiop. 2003, 17(2), 181-184.
Silvère Augustin Ngouela, Guy Feuya, Jean Claude Tchouankeu, Gaston Achoundong, Raymond B.T. Zambou, Etienne Tsamo and 1 more
Bulletin of the Chemical Society of Ethiopia
A new lignan, meiocarpin, and the known compounds, sitosterol and polycarpol, have been isolated from the stem bark of Meiocarpidium lepidotum, Annonaceae. The structure of the new compound was elucidated on the basis of its spectroscopic data. KEY WORDS: Meiocarpidium lepidotum, Annonaceae, lignan Bull. Chem. Soc. Ethiop. 2004, 18(2), 221-224.
Silvère Augustin Ngouela, Barthélemy Nyasse, Etienne Tsamo, Marie‐Christine Brochier, Christophe Morin
Journal of Natural Products
A new trachylobane derivative identified as 7alpha-hydroxytrachyloban-19beta-oic acid (1) has been isolated from the bark of Xylopia aethiopica and its structure elucidated by various NMR techniques and molecular modeling.
Silvère Augustin Ngouela, Etienne Tsamo, Beibam L. Sondengam, Joseph D. Connolly
Journal of Natural Products
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSpathodol, a New Polyhydroxysterol from the Leaves of Spathodea campanulataSilvere Ngouela, Etienne Tsamo, Beibam L. Sondengam, and Joseph D. ConnollyCite this: J. Nat. Prod. 1991, 54, 3, 873–876Publication Date (Print):May 1, 1991Publication History Published online1 July 2004Published inissue 1 May 1991https://pubs.acs.org/doi/10.1021/np50075a023https://doi.org/10.1021/np50075a023research-articleACS PublicationsRequest reuse permissionsArticle Views198Altmetric-Citations12LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
Silvère Augustin Ngouela, Barthélemy Nyasse, Etienne Tsamo, Beibam L. Sondengam, Joseph D. Connolly
Phytochemistry
Silvère Augustin Ngouela, Etienne Tsamo, Beibam L. Sondengam
Planta Medica
Marie G. Tsepeupon Matchide, Herman D. Sonfack Fozeng, Marthe Aimée Tchuente Tchuenmogne, Claudelle S. Djadock Anensong, Wilfried Wembe Koagne, Stijn Anthonissen and 8 more
Biochemical Systematics and Ecology
Clémence Donfack Gouni, Yannick Stéphane Fotsing Fongang, Darline Dize, Georges Bellier Tabekoueng, Donald Ulrich Kenou Kagho, Gabin Thierry M. Bitchagno and 5 more
Phytochemistry Letters
Pierre Leonel K. Tafokeu Taguimjeu, Mariscal Brice Tchatat Tali, Kevine Johane Jumeta Dongmo, Fongang Fotsing Yannick Stéphane, Marie‐Laure Fauconnier, Bruno Ndjakou Lenta and 3 more
SSRN Electronic Journal
Arno Rusel Donfack Nanfack, Hermine Wete Nono, Mehreen Lateef, Maurice Ducret Awouafack, Silvère Augustin Ngouela, Muhammad Shaiq Ali and 1 more
Biochemical Systematics and Ecology
Yves Martial Mba Nguekeu, Takeshi Kodama, Marie G. Tsepeupon Matchide, Kiep Minh, Josker Nghokeng, Gaétan Tchangou Tabakam and 5 more
Fitoterapia
Arno Rusel Donfack Nanfack, Ariane Audrey Sinze Metiave, Faustine L. M. Dongmo, Mehreen Lateef, Maurice Ducret Awouafack, Silvère Augustin Ngouela and 2 more
Biochemical Systematics and Ecology
Hermine Wete Nono, Arno Rusel Donfack Nanfack, Billy Toussie Tchegnitegni, Cyrille Armel Njanpa Ngansop, Faustine Léonie Mafodong Dongmo, Maurice Ducret Awouafack and 6 more
The Cambridge Structural Database
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Marie G. Tsepeupon Matchide, Saw Yu Yu Hnin, Yves Martial Mba Nguekeu, Elodie Gaële Matheuda, Josker Nghokeng, Gaétan Tchangou Tabakam and 6 more
Chemistry & Biodiversity
Abstract A new fructofuranoside glycerol, dryoptkirbioside ( 1 ), along with thirteen known compounds ( 2 ‐ 14 ), was isolated from the MeOH extract of Dryopteris kirbi rhizomes by silica gel column chromatography, Sephadex LH‐20 column chromatography, and semipreparative HPLC. The structure of the new compound was determined by analyses of its spectroscopic data including nuclear magnetic resonance (NMR), and high‐resolution electrospray ionisation mass spectrometry (HR‐ESI‐MS) and chemical conversions. The hexane‐soluble portion and the EAF A fraction showed strong activities against lung (A549), breast (MCF‐7), and cervical (HeLa) human cancer cell lines (IC 50 values ranging from 4.0 to 8.8 μg/mL). Aspidinol P ( 5 ) and aspidinol B ( 6 ) exhibited moderate to low cytotoxicity on the three cell lines (IC 50 values ranging from 20.4 to 58.7 μM). The MeOH extract and hexane‐soluble portion had excellent activities against Staphylococcus aureus and Bacillus subtilis (MICs 11.7 and 23.4 μg/mL), whereas the AcOEt‐ and BuOH‐soluble portions were significantly active on S. aureus (MICs 46.9 and 93.8 μg/mL). The main fractions EAF B , EAF C and nBF B displayed excellent activity against S. aureus (MICs 11.7 and 23.4 μg/mL). Aspidinol B ( 6 ) had significant activity, while aspidinol P ( 5 ) was moderately active against S. aureus and B. subtilis (MICs 42.0 and 89.5 μM).
Hermine Wete Nono, Arno Rusel Donfack Nanfack, Billy Toussie Tchegnitegni, Cyrille Armel Njanpa Ngansop, Faustine L. M. Dongmo, Maurice Ducret Awouafack and 6 more
Phytochemistry
Kevine Johane Jumeta Dongmo, Mariscal Brice Tchatat Tali, Yannick Stéphane Fotsing Fongang, Pierre Leonel K. Tafokeu Taguimjeu, Donald Ulrich Kenou Kagho, Gabin Thierry M. Bitchagno and 4 more
BMC Complementary Medicine and Therapies
Abstract Background Dacryodes edulis is a plant that belongs to the Burseraceae family. It is widely used traditionally alone or in association with other plants in Cameroonian folk medicine to cure wounds, fever, headaches, and malaria. The aim of this work was to investigate the leaves and stem bark of D. edulis with an emphasis on the antiplasmodial and cytotoxic effects of extracts, fractions, and isolated compounds. Methods Extracts, fractions, and some isolated compounds were subjected to antiplasmodial activity screening in vitro against chloroquine-sensitive 3D7 and multidrug resistant Dd2 strains of Plasmodium falciparum using a SyBr Green fluorescence-based assay. The cytotoxicity of active extracts, fractions, and compounds was tested against mammalian Raw cell lines using an in vitro resazurin-based viability assay. The structures of the compounds were determined based on their NMR and MS data. The in vivo toxicity using female BALB/c mice was performed on the most active extract according to the protocol of OECD (2002), guideline 423. Results The hydroethanolic extract from the leaves of D. edulis displayed good antiplasmodial activity with IC 50 values of 3.10 and 3.56 μg/mL respectively on sensitive (3D7) and multiresistant (Dd2) strains of P. falciparum . Of the sixteen compounds isolated, 3,3′,4-tri- O -methylellagic acid ( 4 ) exhibited the highest antiplasmodial activity against Pf Dd2 strains with an IC 50 value of 0.63 μg/mL. All extracts, fractions, and isolated compounds demonstrated no cytotoxicity against Raw cell lines with CC 50 > 250 μg/mL. In addition, the most active extract on both strains of P. falciparum was nontoxic in vivo, with a LD 50 greater than 2000 and 5000 mg/kg. A phytochemical investigation of the stem bark and leaves of D. edulis afforded sixteen compounds, including two xanthones (1–2), three ellagic acid derivatives (3–5), one phenolic compound ( 6 ), one depside ( 7 ), one triglyceride ( 8 ), one auranthiamide acetate ( 9 ), one gallic acid derivative ( 10 ), four triterpenoids ( 11 – 14 ), and two steroids ( 15 – 16 ). Compounds 1 , 2 , 5 , 7 , 8 , and 9 were herein reported for the first time from the Burseraceae family. Conclusion This work highlights the good in vitro antiplasmodial potency of the hydroethanolic extract of the leaves of this plant and that of two isolated constituents (3,3′,4-tri- O -methylellagic acid and ethylgallate) from the plant. These biological results support the use of D. edulis in traditional medicine against malaria.
Gaétan Tchangou Tabakam, Takeshi Kodama, Marthe Aimée Tchuente Tchuenmogne, Nhat Nam Hoang, Battsengel Nomin-Erdene, Silvère Augustin Ngouela and 3 more
Natural Product Research
In the search of cytotoxic dihydrochalcones, this investigation led to the isolation of seven compounds (1-7) from Eriosema glomeratum and the preparation of eight derivatives (8-15). The cytotoxicity of samples was evaluated against lung (A549), breast (MCF-7), and cervical (HeLa) human cancer cells. The CH2Cl2/MeOH extract of the aerial part had strong cytotoxicity against all cells [IC50 11.2 (MCF-7), 8.4 (HeLa) and 13.1 (A549) μg/mL]. A strong activity was also displayed by the n-hexane fraction on MCF-7 (IC50 11.2 μg/mL). The precursor 3 and the derivative 8 were specifically found as strong cytotoxic agents toward MCF-7 (7.6 μM) and HeLa (3.1 μM), respectively and were more effective than the positive control. Derivatives 8 (3.1 μM) and 9 (21.3 μM) against HeLa were most potent than their precursor 3 (23.7 μM). This is the first preparation of 8-14 as well as the cytotoxicity of 3, 4, 8-15, fractions, and extract.
Kevine Johane Jumeta Dongmo, Mariscal Brice Tchatat Tali, Yannick Stéphane Fotsing Fongang, Pierre Leonel K. Tafokeu Taguimjeu, Donald Ulrich Kenou Kagho, Gabin Thierry M. Bitchagno and 4 more
Research Square
Abstract Background Dacryodes edulis is a plant that belongs to the Burseraceae family. It is widely used traditionally alone or in association with other plants in Cameroonian folk medicine to cure wounds, fever, headaches, and malaria. The aim of this work was to investigate the leaves and stem bark of D. edulis with an emphasis on the antiplasmodial and cytotoxic effects on extracts, fractions and isolated compounds. Methods Extracts, fractions, and some isolated compounds were subjected to antiplasmodial activity screening in vitro against chloroquine-sensitive 3D7 and multidrug resistant Dd2 strains of Plasmodium falciparum using a SyBr Green fluorescence-based assay. The cytotoxicity of active extracts, fractions, and compounds was tested against mammalian Raw cell lines using an in vitro resazurin-based viability assay. The structures of the compounds were determined based on their NMR and MS data. The in vivo toxicity using female BALB/c mice was performed on the most active extract according to the protocol of OECD (2001), guideline 423. Results The hydroethanolic extract from the leaves of D. edulis displayed good antiplasmodial activity with IC 50 values of 3.10 and 3.56 µ g/mL respectively on sensitive (3D7) and multiresistant (Dd2) strains of P. falciparum . Of the sixteen compounds isolated, 3,3′,4-tri- O -methylellagic acid ( 4 ) exhibited the highest antiplasmodial activity against Pf Dd2 strains with an IC 50 value of 0.63 µg/mL. All extracts, fractions, and isolated compounds demonstrated cytotoxicity against Raw cell lines with CC 50 > 250 µ g/mL. In addition, the most active extract on both strains of P. falciparum was nontoxic in vivo , with an LD 50 greater than 2000 and 5000 mg/kg. A phytochemical survey of the stem bark and leaves of D. edulis afforded sixteen compounds, including two xanthones ( 1 – 2 ), three ellagic acid derivatives ( 3 – 5 ), one phenolic compound ( 6 ), one depside ( 7 ), one triglyceride ( 8 ), one auranthiamide acetate ( 9 ), one gallic acid derivative ( 10 ), four triterpenoids ( 11 – 14 ), and two steroids ( 15 – 16 ). Compounds 1 , 2 , 5 , 7 , 8 , and 9 were herein reported for the first time from the Burseraceae family. Conclusion This work highlight the good antiplasmodial potency of the hydroethanolic extract of the leaves of this plant and the antiplasmodial activity of 2 of its constituents (3,3′,4-tri- O -methylellagic acid and ethylgallate) in vitro . These biological results confirmed the use of D. edulis in traditional medicine against malaria.
Didérot Tchamo Noungoué, JosetteLinda Toussi Matchi, Guilhem Chaubet, Jérôme Boissier, Isabelle Kuhn, Jean-Claude Tchouankeu and 4 more
Pharmacognosy Magazine
Context: Anonidium mannii (Annonaceae) has been traditionally used in Africa to treat stomach aches, schistosomiasis, and many other illnesses. However, few phytochemical study and no investigation on schistosomiasis have been conducted on this species. This neglected tropical disease, caused by a worm, comes second after malaria as the most devastating parasitical infection. Aim: The goal of this study was to evaluate the anti-Schistosoma mansoni activity of fractions and constituents from A. mannii's stem bark and also to search efficient inhibitors of a recently discovered ectoenzyme of S. mansoni (S. mansoni nicotinamide adenine dinucleotide + catabolizing enzyme [SmNACE]). Materials and Methods: The powdered stem bark of A. mannii was extracted with ethanol/distilled water (80:20). The extract was then subjected to a partial bioguided separation by chromatography means. The structures of compounds were elucidated using modern spectroscopic techniques. Furthermore, isolated and semisynthetic compounds were evaluated for their antischistosomal and cytotoxic activities. Results: Chemical investigation led to the isolation and identification of eight compounds, in the majority, obtained for the first time from this genus. In addition, acetylation reactions were carried out to afford a new semisynthetic derivative. Preliminary biological screening of the extracts and compounds showed very good activities from antiparasitic and enzymatic tests and also very good percentage of cell viability evaluation. Conclusion: Like praziquantel drug, gallic acid exhibited full anthelmintic activity at concentration of 100 μM. On the other hand, piperolactam D showed important inhibition on SmNACE (IC50 10 μM). Thus, standardization of bioactive fraction can help in improving traditional medicine. The optimization of those two compounds will enhance their selectivity/effectiveness and could be used as seed for the development of new remedies against schistosomiasis. Further, the study will be focus on other pathogens species of Schistosoma genus.
Inest Larissa Tchomtchoua Bouzeko, Faustine L. M. Dongmo, Blanche L. Ndontsa, Cyrille Armel Njampa Ngansop, Rodrigue Keumoe, Gabin Thierry M. Bitchagno and 9 more
Biochemical Systematics and Ecology
Yannick Stéphane Fotsing Fongang, Angelbert F. Awantu, Jean Jules Kezetas Bankeu, Mehreen Lateef, Bruno Ndjakou Lenta, Muhammad Shaiq Ali and 1 more
Chemistry of Natural Compounds
Angelbert F. Awantu, Godfred A. Ayimele, Jean Jules Kezetas Bankeu, Edouard Akono Nantia, Patrick Valère Tsouh Fokou, Fabrice Fekam Boyom and 3 more
International Journal of Organic Chemistry
Two new hydralazine hydrochloride-derived Schiff bases: (E)-1-(Phthalazin- 1-yl)-1-[(Pyridin-2-yl)Ethylidene]Hydralazine (PPEH), and 1-[2-(1-(pyridine- 3-yl)ethylidene)hydrazinyl]phthalazine (PEHP), were synthesized and partially characterized by spectroscopic and crystallographic methods including IR and X-ray. The single-crystal X-ray diffraction (SCXRD) analysis of PEHP indicates that the hydralazine moiety of both ligands possesses the exocyclic C=N bond. Both, PPEH and PEHP were tested as antimicrobials and antiparasites. Just PEHP could be considered as slightly antiplasmodial and antibacterial agent. In effect, PPEH showed low antimicrobial activity against one bacterial strain with Minimum Inhibitory Concentration (MIC) value of 250 μg/ml while PEHP showed very interesting activity against 18 out of 19 bacterial strains with MIC of 31.25 - 250 μg/ml compared to the standard drug, amoxicillin. PPEH and PEHP showed higher reducing activity on ferric ions compared to Vitamin C. On the other hand, both hidrazaline synthetized derivatives showed as better reducing agents than Vitamin C on ferric ions, while again, only the PEHP showed slightly high inhibition of lipid peroxidation using Vitamin C as standard. Regarding their catalase activity, both compounds showed concentration dependent effect, but Vitamin C continued showing a higher stimulatory effect on the enzyme activity. Additionally, while PPEH showed less than 80% inhibition in the preliminary antiplasmodial assay and so was not considered for the dose-response studies, PEHP displayed an inhibition percentage of 83.60% and 50% Inhibitory Concentration (IC50) value of 44.13 μg/mL compared to the standard drug, artemisinin and was classified as slightly active.
Hardo Suzy Donfack Chouna, Jean Jules Kezetas Bankeu, Yannick Stéphane Fotsing Fongang, Darline Dize, Beaudelaire Kemvoufo Ponou, Gabin Thierry M. Bitchagno and 6 more
Phytochemistry Letters
Dietagoum Madjouka Stephanie, Fongang Fotsing Yannick Stéphane, Bankeu Kezetas Jean Jules, Fatma Kaaniche, Isabelle Kamga Mawabo, Silvère Augustin Ngouela and 2 more
Natural Product Research
The phytochemical investigation of the methanol extract of the stem bark of Gilbertiodendron dewevrei led to the isolation of two new secondary metabolites, 5,7-dihydroxy-4′-methoxyisoflavan-2,4-dione (1) and 23-hydroxy-2-tricosanone (2) along with 19 known compounds (3–21). The structure of these compounds were established by interpretation of their spectral data, mainly HR-TOFESIMS, 1 D NMR (1H, 13C and DEPT) and 2 D NMR (1H–1H COSY, HSQC, HMBC, and NOESY), and by comparison with those reported in the literature. The methanol extract and some isolates were screened for their antiradical, antibacterial, and inhibitory properties against acetylcholinesterase.
Clarice Noussi Djouwoug, Florence Tsofack Ngueguim, Racéline Kamkumo Gounoue, Clémence Donfack Gouni, Antoine Kavaye Kandeda, Jean Philippe Djientcheu Tientcheu and 6 more
Evidence-based Complementary and Alternative Medicine
Bridelia atroviridis Müll. Arg. (B. atroviridis ) is a plant used in Cameroonian traditional medicine to manage diabetes. The effects of hydroethanolic barks extract from B. atroviridis were evaluated on diabetes disorders including hematology, inflammatory, and oxidative stress parameters. The in vitro antioxidant capacity of the hydroethanolic bark extract (70 : 30) was evaluated. Nicotinamide‐/streptozotocin‐induced diabetic rats were daily treated with the B. atroviridis extract for fifteen days. Glycemia were evaluated every 5 days, insulin sensibility test was performed, and haematological, inflammatory, and oxidative stress parameters were analysed. Histomorphometry of the pancreas was realized. The extract was able to scavenge free radicals in vitro and decrease significantly the blood glucose levels. The treatment resulted in a significant alleviation of insulin resistance, anemia, leukocytopenia, and thrombocytopenia observed in untreated diabetic rats. The extract significantly decreased proinflammatory cytokines TNF‐ α , IL‐1 β , and IL‐10. The rate of reduced glutathione was increased in the pancreas, whereas the catalase activity and nitrite concentration were decreased. Diabetic control showed a reduced size of Langerhans islet, whereas the size of islets was large in treated groups. The hydroethanolic extract of B. atroviridis was able to improve glycemia and alleviate haematological and inflammatory parameters disorders observed in diabetic conditions, probably due to its antidiabetic, anti‐inflammatory, and antioxidant capacities.
Clarice Noussi Djouwoug, Racéline Kamkumo Gounoue, Florence Tsofack Ngueguim, Jaures Marius NankapTsakem, Clémence Donfack Gouni, Antoine Cavaye Kandeda and 5 more
Journal of Ethnopharmacology
Josette Linda Toussi Matchi, Didérot Tchamo Noungoué, Isabelle Kuhn, Jérôme Boissier, Jean Claude Tchouankeu, Marc Nothisen and 5 more
Natural Product Research
A new alkaloid, manniindole 1, together with four known compounds: aristolactam AII 2, aristolactam BII 3, piperolactam D 4 and polycarpol 5 were isolated from the crude extract EtOH-H2O (8:2) of the roots of Anonidium mannii by chromatographic separation. The structure elucidation was performed on the basis of a spectroscopic analysis (IR, HRESI MS, 1D and 2D NMR) as well as a comparison of their spectral data with those reported in the literature. For the first time, the crude extract and those isolated compounds were evaluated for their anti-schistosomal activity against Schistosoma mansoni and for cytotoxicity activity against Huh7 and A549 cells. Furthermore, they were also tested in vitro on the recent characterized Schistosoma mansoni NAD+ catabolizing enzyme (SmNACE) for their impact on this enzyme which is localized on the outer surface of the adult parasite. Compound 2 displayed quite good worm killing capability, while 4 showed significant inhibition of SmNACE.
Angelbert F. Awantu, Yannick Stéphane Fotsing Fongang, Godfred A. Ayimele, Edouard Akono Nantia, Patrick Valère Tsouh Fokou, Fabrice Fekam Boyom and 3 more
International Journal of Organic Chemistry
Two novel Schiff bases, 3-[1-(2-(phthalazin-1-yl)hydrazono)ethyl)-1,3-oxa- zinane (PHEO) and 2-[(2-(phthalazin-1-yl)hydrazono)methyl]phenol (PHMP), derived from hydralazine hydrochloride, an effective drug against hypertension, were synthesized and characterized by spectroscopic methods, Infrared (IR), Proton Nuclear Magnetic Resonance (1H NMR) and Carbon-13 Nuclear Magnetic Resonance (13C NMR). PHEO showed low antimicrobial activity against one bacterial strain with MIC value of 250 μg/ml while PHMP showed interesting activity against 4 bacterial strains with MIC of 31.25 - 250 μg/ml compared to the standard drug, amoxicillin. PHEO and PHMP showed higher reducing activity on ferric ions compared to Vitamin C. On lipid peroxidation, PHEO showed higher inhibition while PHMP showed lower inhibition compared to Vitamin C. Both compounds presented lower stimulating effect and lower catalase activity compared to the standard Vitamin C. PHEO and PHMP showed less than 80% inhibition in the preliminary antiplasmodial assay and so were not considered for the dose-response studies.
Jean Jules Kezetas Bankeu, Donald Ulrich Kenou Kagho, Yannick Stéphane Fotsing Fongang, Rufin Marie Kouipou Toghueo, Brice Mittérant Mba’ning, Guy Feuya and 6 more
Journal of Natural Products
Three previously undescribed indole alkaloids, named latifolianine A ( 1 ) and latifoliaindoles A and B ( 2 and 3 ), along with 10 known compounds ( 4 – 13 ), were isolated from the heartwood of Nauclea latifolia . Their structures were elucidated based on the analysis of their NMR and MS data. Latifolianine A ( 1 ) represents an unusual and unprecedented monoterpene indole alkaloid unit condensed with an ursane-type pentacyclic triterpenoid moiety. Plausible biogenetic routes toward latifolianine A ( 1 ) and latifoliaindoles A and B ( 2 and 3 ) were proposed. All the isolates were assessed in vitro for their inhibitory effects on Haemophilus influenzae . Naucleidinal ( 7 ) exhibited potent antibacterial activity (MIC value of 3.1 μg/mL) as compared to a reference drug, ciprofloxacin (MIC value of 1.6 μg/mL).
Fongang Fotsing Yannick Stéphane, Amadou Dawé, Awantu Angelbert Fusi, Bankeu Kezetas Jean Jules, Kagho Kenou Donald Ulrich, Mehreen Lateef and 3 more
Natural Product Research
The phytochemical investigation of the methanol extract of the bark of Croton oligandrus Pierre ex Hutch yielded a new clerodane-type diterpenoid crotoliganfuran (1) along with ten other compounds including 12-epicrotocorylifuran (2), lupeol (3), syringic acid (4), aleuritolic acid acetate (5), aleuritolic acid (6), scopoletin (7), geddic acid (8), β-sitosterol (9), vanilic acid (10) and stigmastane-3,6-dione (11). Their structures were established by spectroscopic means. The extract and all the isolates were screened for their inhibitory properties against butyrylcholinesterase and urease enzymes, respectively. The extract and compounds 1, 4 and 7 displayed the most potent urease inhibitory properties with IC50 values, 22.2, 26.7 and 28.5 µM, respectively. Compound 9 was the most active of all the tested compounds against butyrylcholinesterase enzyme with an IC50 value of 36.3 µM.
Flaure Rosette Ehawa Essoung, Brice Mittérant Mba’ning, Samira A. Mohamed, Wilber Lwande, Silvère Augustin Ngouela, Etienne Tsamo and 3 more
Phytochemistry Letters
Brice Mittérant Mba’ning, Bruno Lenta Ndjakou, Ferdinand Mouafo Talontsi, Alain Méli Lannang, Birger Dittrich, Silvère Augustin Ngouela and 3 more
The Cambridge Structural Database
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Marthe Aimée Tchuente Tchuenmogne, Thierry Kammalac Ngouana, Sebastian Gohlke, Rufin Marie Kouipou Toghueo, Abdulselam Aslan, Müslüm Kuzu and 7 more
Preprints.org
The chemical investigation of the anti-yeast methanol extract from the stem bark of Terminalia mantaly led to the isolation of seven compounds: 3-O-methyl-4-O-&alpha;-rhamnopyranoside ellagic acid (1), 3-O-mehylellagic acid (2), arjungenin or 2,3,19,23-tetrahydroxyolean-12-en-28-o&iuml;c acid (3), arjunglucoside or 2,3,19,23-tetrahydroxyolean-12-en-28-o&iuml;c acid glucopyranoside (4), 2&alpha;,3&alpha;,24-trihydroxyolean-11,13(18)-dien-28-o&iuml;c acid (5), stigmasterol (6), stigmasterol 3-O-&beta;-D-glucopyranoside (7). Their structures were established by means of spectroscopic analysis and comparison with published data. Compounds 1-5 were tested in vitro for activity against three pathogenic yeast isolates, Candida albicans, Candida parapsilosis and Candida krusei. The activity of compounds 1, 2 and 4 were comparable to that of the reference compound fluconazole (MIC values below 32 &micro;g/ml) against the three tested yeast isolates. They were also tested for inhibitory properties against four enzymes of metabolic significance: Glucose-6-Phosphate Deshydrogenase (G6PD), human erythrocyte Carbonic anhydrase I and II (hCA I and hCA II), Glutathione S-transferase (GST). Compound 4 showed highly potent inhibitory property against the four tested enzymes with overall IC50 values below 4 &micro;M and inhibitory constant (Ki) &lt;3 &micro;M.
Jean Emmanuel Mbosso Teinkela, Xavier Siwe‐Noundou, Edwige Laure Nguemfo, F. Meyer, Alfred Djoukoue, Pierre Van Antwerpen and 6 more
Fitoterapia
Jean Emmanuel Mbosso Teinkela, Jules Clément Nguedia Assob, F. Meyer, Erik V. Donfack, Bruno Lenta Ndjakou, Silvère Augustin Ngouela and 4 more
Pharmaceutical Biology
CONTEXT: African medicinal plants represent a prominent source of new active substances. In this context, three plants were selected for biological investigations based on their traditional uses. OBJECTIVE: The antimicrobial and anti-proliferative features of three plants used for medicinal purpose were evaluated. MATERIALS AND METHODS: The antimicrobial activities of methanol extracts of Ficus bubu Warb. (Moraceae) stem bark and leaves, of Spathodea campanulata P. Beauv. (Bignoniaceae) flowers, as well as those of Carica papaya Linn. (Caricaceae) latex, were determined using the microbroth dilution method against a set of bacteria and fungi pathogens including: Enterococcus faecalis, Staphylococcus aureus, S. saprophyticus, S. epidermididis, Escherichia coli, Klebsiella pneumonia, Salmonella typhimurium, Candida albicans, and Trichophyton rubrum. The tested concentrations of extracts ranged from 2500.0 to 2.4 μg/mL and MIC values were evaluated after 24 h incubation at 37 °C. Subsequently, MTT assay was used to estimate anti-proliferative activity of these methanol extracts and of F. bubu latex on three human cancer cell lines (U373 glioblastoma, A549 NSCLC, and SKMEL-28 melanoma). RESULTS: The methanol extract of F. bubu stem bark exhibited the highest antimicrobial activity against C. albicans with a MIC value of 9.8 μg/mL, while the F. bubu latex and the methanol extract of F. bubu leaves induced significant anti-proliferative activity against lung (IC50 values of 10 and 14 μg/mL, respectively) and glioma (IC50 values of 13 and 16 μg/mL, respectively) cancer cells. CONCLUSION: These results indicate that effective drugs could be derived from the three studied plants.
Bruno Ndjakou Lenta, Jules Ngatchou, Marcel Frese, Flora Ladoh-Yemeda, Stève Olugu Voundi, Flore Nardella and 7 more
Zeitschrift für Naturforschung B
Abstract The ethyl acetate extracts prepared from the mycelia of three endophytic fungi Purpureocillium lilacinum, Aspergillus sp., and Fusarium sp., isolated from the roots of Rauvolfia macrophylla (Apocynaceae) were screened for their antiprotozoal activity in vitro against Plasmodium falciparum (NF54), Leishmania donovani , Trypanosoma brucei rhodesiense, and Trypanosoma cruzi . Amongst these extracts, the one from P. lilacinum showed potent antileishmanial activity against L. donovani (IC 50 value of 0.174 μg mL −1 ) with good selectivity (SI=94.9) toward the L6 cell line, whereas the other extracts were inactive and not selective. The fractionation and purification of the active extract from P. lilacinum by column chromatography over silica gel yielded a new ergochromone derivative ( 1 ), together with six known compounds: (22 E ,24 R )-stigmasta-5,7,22-trien-3- β -ol ( 2 ), (22 E ,24 R )-stigmasta-4,6,8(14),22-tetraen-3-one ( 3 ), emodin ( 4 ), chrysophanol ( 5 ), aloe-emodin ( 6 ), and palmitic acid, whose structures were elucidated spectroscopically. Compound 1 was tested in vitro for its antiparasitic activities against the above listed parasites and for its antimicrobial activity against Staphylococcus aureus , Bacillus cereus , Listeria monocytogenes , Escherichia coli , Providencia stuartii , Klebsiella pneumoniae , and Pseudomonas aeruginosa . The compound displayed potent antileishmanial activity against L. donovani with an IC 50 value of 0.63 μg mL −1 (0.87 μ m ) with good selectivity (SI=49.5) toward the L6 cell line. It also exhibited good antibacterial activity against three of the tested microbial strains B. cereus , E. coli ATCC879, and P. stuartii ATCC29916 with minimum inhibitory concentrations below 62.6 μg mL −1 . Compound 1 is thus a promising active compound that could be investigated for antileishmanial and antimicrobial drug development.
Brice Mittérant Mba’ning, Bruno Lenta Ndjakou, Ferdinand Mouafo Talontsi, Alain Méli Lannang, Birger Dittrich, Silvère Augustin Ngouela and 3 more
Zeitschrift für Naturforschung B
Abstract A mixture of two compounds with potent antiplasmodial activity in vitro against the W2 strain of Plasmodium falciparum (half maximal inhibitory concentration, 1.12 μg/mL) was obtained in a previous investigation of the CH 2 Cl 2 -MeOH extract of the seeds of Salacia longipes var. camerunensis. Separation by column chromatography led now to the isolation of salaterpene E ( 1 ) and (1 R ,2 R ,4 S ,5 S ,6 R ,7 R ,9 S ,10 R )-2-acetoxy-1,6,9-tribenzoyloxy-4-hydroxy-dihydro- β -agarofuran ( 2 ). The structure of 1 was elucidated by spectroscopic analysis, and its absolute configuration was established unambiguously by means of single-crystal X-ray diffraction. Also the absolute configurations of the recently described salaterpenes A ( 2a ) and D ( 2b ) were determined by this method using the anomalous scattering of the oxygen atoms only.
Bruno Ndjakou Lenta, Joél T. Ateba, Jean Rodolphe Chouna, Makoah N. Aminake, Flore Nardella, Gabriele Pradel and 5 more
Helvetica Chimica Acta
Abstract Phytochemical investigation of the leaves of Phragmanthera capitata collected on Cassia spectabilis tree led to the isolation of two natural lactones, rel ‐(1 R ,5 S ,7 S )‐7‐[2‐(4‐hydroxyphenyl)ethyl]‐2,6‐dioxabicyclo[3.3.1]nonan‐3‐one ( 1 ) and 4‐{2‐[ rel ‐(1 R ,3 R ,5 S )‐7‐oxo‐2,6‐dioxabicyclo[3.3.1]non‐3‐yl]ethyl}phenyl 3,4,5‐trihydroxybenzoate ( 2 ) together with the known compounds betulinic acid ( 3 ), dodoneine ( 4 ), quercetin 3‐ O ‐ α ‐ L ‐rhamnopyranoside ( 5 ), quercetin 3‐ O ‐ α ‐ L ‐arabinofuranoside ( 6 ), quercetin ( 7 ), betulin ( 8 ), lupeol ( 9 ), and sitosterol ( 10 ). Their structures were established by means of modern spectroscopic techniques, and the relative configuration of compound 1 was confirmed by X‐ray analysis. Compounds 1 and 2 were tested in vitro for their antiplasmodial activity against the Plasmodium falciparum chloroquine sensitive‐strains NF54 and 3D7. Compound 2 exhibited good antiplasmodial activity against both strains with IC 50 of 2.4 and 4.9 μ M , respectively, while compound 1 was inactive.
Rosine Fotsing Ngamgwe, Raoul Yankam, Jean Rodolphe Chouna, Christian Lanz, Julien Furrer, Stefan Schürch and 5 more
PubMed
Phytochemical investigation of a dichloromethane-methanol (1:1) extract of the fruit pericarp of Omphalocarpum procerum which exhibited antiplasmodial activity during preliminary screening led to the isolation of the new fatty ester triterpenoid 3β-hexadecanoyloxy-28-hydroxyolean-12-en-11-one (1), together with five known compounds 2-6. The structure of the new compound as well as those of the known compounds was established by means of spectroscopic methods and by comparison with previously reported data. Compounds 1- 4 were evaluated in-vitro for their cytotoxicity against L6 cell lines and antiprotozoal activities against Plasmodium falciparum, Leishmania donovani, Trypanosoma brucei rhodesiense and Trypanosoma cruzi (species responsible for human malaria, visceral leishmaniasis, African trypanosomiasis and Chagas disease, respectively). The tested compounds showed weak to moderate antiprotozoal activity and, no significant effect was detected regarding their cytotoxic potency.
Emmanuel Jean Teinkela Mbosso, René Wintjens, Bruno Ndjakou Lenta, Silvère Augustin Ngouela, Michel Rohmer, Etienne Tsamo
Chemistry & Biodiversity
A chemical investigation of the Glyphaea brevis leaves and of the Monodora myristica fruits led to the identification of thirteen compounds, seven linear long-chain aliphatic compounds, 1, 2, 4, 6, and 9-11, three steroids, 3a, 3b, and 7, two triterpenes, 5a and 5b, and one polyol, 8. The compounds 2 and 8, previously mentioned in the literature, are here characterized by their complete (1)H- and (13)C-NMR assignments. This is the first report of a full NMR assignment for linear fatty acid esters of aliphatic primary alcohols and for meso-erythritol. Compound 5b and 8 were isolated for the first time from plant extracts of the Tiliaceae family, and compounds 9-11 from the Annonaceae plant family. Our results constitute the basis for further chemotaxonomic studies on the two species.
Erik V. Donfack, Bruno N. Lenta, Michel D. T. Kongue, Yannick F. Fongang, Silvère Augustin Ngouela, Etienne Tsamo and 2 more
ChemInform
Abstract [isolation and structure elucidation of the new alkaloid naucleactonin D (I) as well as biochemical investigations]
Aimee M. T. Tchuenmogne, Erik V. Donfack, Michel D. T. Kongue, Bruno N. Lenta, Silvère Augustin Ngouela, Etienne Tsamo and 3 more
Bulletin of the Korean Chemical Society
Department of Structural Chemistry, University of Gottingen, Tammannstr. 4, 37077 Gottingen, GermanyReceived July 3, 2013, Accepted September 9, 2013Key Words : Inga edulis, Ingacamerounol, Flavonol, Fabaceae-Mimosoideae, CytotoxicityThe genus Inga (Fabaceae-Mimosoideae), native in tropi-cal and subtropical America (Mexico to Argentina) com-prises about 300 species. Many of them were used by localhealers to treat illnesses such as malaria, diarrhoea, ulcers,mouth inflammations and leishmaniasis.
Anar Sahib Gojayev, Jean Jules Kezetas Bankeu, Angelbert F. Awantu, Eric René Sieliatchom Nkanwen, Muhammad Shaiq Ali, Bruno Ndjakou Lenta and 4 more
Bangladesh Journal of Pharmacology
Phytochemical investigation of the stem bark and the trunk of Chythrantus claneianus led to the isolation of six known compounds named β-sitosterol (1), umbelliferone (2), scopoletin (3), benjaminamide (4), β-sitosterol-3-O-β-D-glucopyranoside (5) and panconoside B (6). All these compounds were isolated for the first time from this plant species. The chemical structures of isolates were elucidated on the basis of 1 and 2 D-NMR spectra and other spectroscopic techniques including UV–vis, FT-IR, HR-ESIMS and HR-FABMS. The isolates were tested in vitro for their inhibitory properties towards xanthine oxidase enzyme. Compounds 2, 3 and 6 showed weak inhibitory activities on the enzyme with IC50 values ranging from 307 µM for compound 6 to 475 µM for compound 3, while the extract and compounds 1, 4 and 5 showed extremely weak activities with inhibition percentage less than 50%.
Erik V. Donfack, Bruno N. Lenta, Michel D. T. Kongue, Yannick F. Fongang, Silvère Augustin Ngouela, Etienne Tsamo and 2 more
Zeitschrift für Naturforschung B
Phytochemical investigation of the roots and fruits of Mitragyna inermis (Rubiaceae) resulted in the isolation of a new indole alkaloid, named naucleactonin D (1), together with fourteen known compounds: nauclefiline (2), naucleficine (3), nauclefidine (4), angustoline (5), angustine (6), barbinervic acid (7), quinovic acid 3-O-a-L-rhamnopyranoside (8), betulinic acid (9), a mixture of ursolic (10) and oleanolic acid (11), a mixture of stigmasterol and b-sitosterol, b-sitosterol 3-O- b-D-glucopyranoside, and strictosamide (12) as the major compound. The structures of the isolated compounds were elucidated by detailed spectroscopic analysis and by comparison with published data. No 13 C NMR data for 2 and 3 exist in the literature and compounds 2, 3, 5, 7, and 12 are reported for the first time from the genus Mitragyna. The crude extract and isolated compounds were tested in vitro for their preliminary cytotoxicity against brine shrimps (Artemia salina).
Jean Jules Kezetas Bankeu, Rustamova Khayala, Bruno Ndjakou Lenta, Didérot Tchamo Noungoué, Silvère Augustin Ngouela, Sufyan Awad Alkarim Mustafa and 7 more
Journal of Natural Products
Phytochemical investigation of the figs of Ficus mucuso led to the isolation of three new isoflavone dimer derivatives, mucusisoflavones A-C (1-3), together with 16 known compounds. Some of the isolates were tested in vitro for their inhibitory properties toward β-glucuronidase and Plasmodium falciparum enoyl-ACP reductase (PfENR) enzymes. Compound 1 (IC₅₀) 0.68 μM) showed inhibitory activity on β-glucuronidase enzyme, while 3 (IC₅₀) 7.69 μM) exhibited a weak inhibitory activity against P. falciparum enoyl-ACP reductase (PfENR).
Brice Mittérant Mba’ning, Bruno Ndjakou Lenta, Silvère Augustin Ngouela, Didérot Tchamo Noungoué, Ferdinand Tantangmo, M. Talontsi and 2 more
Zeitschrift für Naturforschung B
Phytochemical investigation of the roots of Salacia longipes var. camerunensis led to the isolation of a new triterpenoid, salacetal (1), together with the known compounds mangiferin, 2-hydroxy- 3-oxo-D:A-friedooleanan-29-oic acid, β -sitosterol, and stigmasterol. The structure of the new compound as well as those of the known compounds were established by means of spectroscopic methods and by comparison with reported data.
Jean Jules Kezetas Bankeu, Sufyan Awad Alkarim Mustafa, Anar Sahib Gojayev, Bruno Djakou Lenta, Didérot Tchamo Noungoué, Silvère Augustin Ngouela and 7 more
Chemical and Pharmaceutical Bulletin
Two new sphingolipids mucusamide (1) and mucusoside (2) have been isolated from methanol soluble part of the stem bark of Ficus mucuso WELW., together with fifteen known secondary metabolites including cellobiosylsterol (3), β-sitosterol (4), stigmasterol (5), β-sitosterol 3-O-β-D-glucopyranoside (6), lupeol acetate (7), ursolic acid (8), procatechuic acid (9), 2-methyl-5,7-dihydroxychromone 8-C-β-D-glucoside (10), apigenin (11), (-)-epicatechin (12), (+)-catechin (13), N-benzoyl-L-phenylalanilol (14), α-acetylamino-phenylpropyl α-benzoylamino-phenylpropionate (15), asperphenamate (16) and bejaminamide (17). Structures of compounds 1 and 2 were elucidated by spectroscopic analysis and chemical methods.
René F. Soh, Jean K. Bankeu, Bruno N. Lenta, Brice Mittérant Mba’ning, Silvère Augustin Ngouela, Etienne Tsamo and 1 more
ChemInform
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Emmanuel Jean Teinkela Mbosso, Silvère Augustin Ngouela, Jules Clément Nguedia Assob, Véronique Penlap Beng, Michel Rohmer, Etienne Tsamo
Journal of Ethnopharmacology
Ferdinand Tantangmo, Bruno Ndjakou Lenta, Silvère Augustin Ngouela, Louis Kamdem, Bernard Weniger, Etienne Tsamo and 2 more
Helvetica Chimica Acta
Abstract Phytochemical investigation of the bark and leaves of Pancovia laurentii (Sapindaceae) resulted in the isolation of a new ceramide and a new cerebroside, named pancoviamide ( 1 ), and pancovioside ( 2 ) respectively, together with six known compounds: uracil, ( R )‐ N ‐[(1 S ,2 S ,3 R )‐2,3‐dihydroxy‐1‐(hydroxymethyl)heptadec‐5‐en‐1‐yl]‐2‐hydroxytetracosanamide, stigmasta‐7,22‐dien‐3‐ol, β ‐stitosterol, β ‐sitosterol 3‐ O‐β ‐ D ‐glucopyranoside, and 2,3‐dihydroxypropyl pentadecanoate. The structures of 1 and 2 were determined by means of spectroscopic methods. Compounds 1 and 2 were tested in vitro for their antiprotozoal properties against several protozoa and for their cytotoxicity.
Diderot Noungoué Tchamo, L. Brelot, C. Antheaume, Silvère Augustin Ngouela, Annelise Lobstein
The Cambridge Structural Database
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Erasmienne Tambou Ngouamegne, René Soh Fongang, Silvère Augustin Ngouela, Fabrice Fekam Boyom, Michel Rohmer, Etienne Tsamo and 2 more
The Cambridge Structural Database
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Didérot Tchamo Noungoué, Cyril Antheaume, Mehdi Chaabi, Bruno Lenta Ndjakou, Silvère Augustin Ngouela, Annelise Lobstein and 1 more
ChemInform
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Bruno Ndjakou Lenta, Krishna Prasad Devkota, Silvère Augustin Ngouela, Fabrice Fekam Boyom, Quamar Naz, M. Iqbal Choudhary and 3 more
ChemInform
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Erasmienne Tambou Ngouamegne, René Soh Fongang, Silvère Augustin Ngouela, Fabrice Fekam Boyom, Michel Rohmer, Etienne Tsamo and 2 more
ChemInform
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Fabien Zelefack, Marie‐Geneviève Dijoux‐Franca, David Guilet, Silvère Augustin Ngouela, Bruno Ndjakou Lenta, Nicolás Fabre and 1 more
Planta Medica
Four new xanthone derivatives, named butyraxanthone A ( 1 ), B ( 2 ), C ( 3 ) and D ( 4 ), have been isolated from the stem bark of Pentadesma butyracea ( Clusiaceae), together with six known xanthones [1,2] and one triterpenoid (lupeol). The structural elucidation of the new compounds was established on the basis of 1D and 2D NMR and HR-EIMS spectroscopic analysis. The anti-plasmodial activities of these compounds were evaluated, in culture against FCB1 strain of Plasmodium falciparum parasites. (IC 50 of 3.0 and 2.7µg/mL for compounds 1 and 2 respectively ). Compound 4 showed a potent cytotoxic activity against MCF-7 cells with an IC 50 value of 1.3µg/mL. Acknowledgements: The authors thank the „Agence Universitaire de la Francophonie (A.U.F.)“ for fellowship awarded to F. Zelefack at University Lyon I, France. References: 1. Suksamrarn, S. et al. (2006) Chem. Pharm. Bull. 54: 301–305. 2. Panthong, K. et al. (2006) Phytochemistry 67: 999–1004.
Erasmienne Tambou Ngouamegne, René Soh Fongang, Silvère Augustin Ngouela, Fabrice Fekam Boyom, Michel Rohmer, Etienne Tsamo and 2 more
Chemical and Pharmaceutical Bulletin
From the ethyl acetate extract of the stem bark of Endodesmia calophylloides (Guttiferae), a novel friedelane triterpenoid named endodesmiadiol (1), as well as the known compounds friedelin (2), canophyllol (3), canophyllal (4), cerin (5), morelloflavone (6), volkensiflavone (7), 8-deoxygartanin (8), 3 beta-acetoxyoleanolic acid (9) and 1,8-dihydroxy-3-isoprenyloxy-6-methylxanthone (10) have been isolated. The structures of these compounds were established by spectroscopic analysis, and the relative configuration of endodesmiadiol (1) was confirmed by X-ray diffraction. The antiplasmodial activity of the isolated compounds was evaluated against the W2 strain of Plasmodium falciparum which is resistant to chloroquine and other antimalarial drugs. All the compounds were found to be active with IC50 values ranging from 7.2 to 23.6 microM. The IC50 of endodesmiadiol was found to be 11.8 microM.
Diderot Noungoué Tchamo, Lydia Brelot, Cyril Antheaume, Silvère Augustin Ngouela, Annelise Lobstein
Acta Crystallographica Section E Structure Reports Online
The title compound, C(22)H(18)O(7), also known as laurentiquinone B, is a new anthraquinone which was isolated from Vismia laurentii, a Cameroonian medicinal plant. The asymmetric unit contains two independent mol-ecules. Each of them contains four fused rings, three of which are coplanar and typical of anthracene, while the heterocyclic rings adopt envelope conformations. Intra-molecular O-H⋯O hydrogen bonds result in the formation of two planar rings, which are also almost coplanar with the adjacent rings. In the crystal structure, inter-molecular O-H⋯O and C-H⋯O hydrogen bonds link the mol-ecules and a π-π contact is also present [centroid-centroid distance = 3.967 (3) Å].
Emmanuel Jean Teinkela Mbosso, Silvère Augustin Ngouela, Jules Clément Nguedia Assob, Véronique Penlap Beng, Michel Rohmer, Etienne Tsamo
Natural Product Research
Spathoside, a new cerebroside was isolated from the stem bark of Spathodea campanulata, besides known compounds (n-alkanes, linear aliphatic alcohols, sitosterol and their esters, beta-sitosterol-3-O-beta-D-glucopyranoside, oleanolic acid, pomolic acid, p-hydroxybenzoic acid and phenylethanol esters). The structures of the isolated compounds were established by spectroscopic studies. The antibacterial activity of the isolated compounds against a wide range of microorganisms was examined. They inhibited significantly the growth of some gram-positive and -negative bacteria.
Bruno N. Lenta, Bernard Weniger, Cyril Antheaume, Didérot Tchamo Noungoué, Silvère Augustin Ngouela, Jules Clément Nguedia Assob and 4 more
Phytochemistry
Bruno Ndjakou Lenta, Silvère Augustin Ngouela, Fabrice Fekam Boyom, Ferdinand Tantangmo, Guy Raymond Feuya Tchouya, Etienne Tsamo and 3 more
Chemical and Pharmaceutical Bulletin
Bazouanthrone (1), a new anthrone derivative, has been isolated from the root bark of Harungana madagascariensis, together with known compounds, feruginin A (2), harunganin (3), harunganol A (4), harunganol B (5), friedelan-3-one (6) and betulinic acid (7). The structure of the compound (1) was assigned as 3,5,8,9-tetrahydroxy-2,4,4-tri-(3,3-dimethylallyl)-6-methyl-1-(4H)-anthracenone, by means of spectroscopic analysis. The anti-plasmodial activity of the isolated compounds was evaluated in culture against W2 strain of Plasmodium falciparum. All the compounds were found to be active against the Plasmodium parasites with bazouanthrone (1) showing particular potency (IC50=1.80 microM).
Bruno Ndjakou Lenta, Silvère Augustin Ngouela, Fabrice Fekam Boyom, Ferdinand Tantangmo, Guy Raymond Feuya Tchouya, Etienne Tsamo and 3 more
ChemInform
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Joseph Ngoupayo, Didérot Tchamo Noungoué, Bruno N. Lenta, Turibio Kuiate Tabopda, Shamsun Nahar Khan, Silvère Augustin Ngouela and 2 more
Natural Product Communications
Brevipsidone (1), a new depsidone was isolated from the methanol extract of the stem bark of Garcinia brevipedicellata together with known damnacanthal (2), pilloin (3), scopoletin (4). The structure of the new compound was determined by analysis of spectroscopic data. Compounds 1–4 were evaluated for their α-glucosidase inhibition effect and showed significant inhibitory activity.
J.J. Bankeu Kezetas, Bruno Ndjakou Lenta, Silvère Augustin Ngouela, Etienne Tsamo, Norbert Sewald, B. Neumann and 1 more
The Cambridge Structural Database
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Bruno Ndjakou Lenta, Didérot Tchamo Noungoué, Krishna Prasad Devkota, Patrice A. Fokou, Silvère Augustin Ngouela, Etienne Tsamo and 1 more
The Cambridge Structural Database
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Didérot Tchamo Noungoué, Bruno Ndjakou Lenta, Annelise Lobstein, Silvère Augustin Ngouela, Etienne Tsamo
The Cambridge Structural Database
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Pierre Watcho, Fabien Zelefack, TB Nguelefack, Silvère Augustin Ngouela, PB Telefo, Pièrre Kamtchouing and 2 more
African Journal of Traditional Complementary and Alternative Medicines
The effects of Mondia whitei Hook (Skeels) were studied on the sexual behaviour and some fertility parameters of sexually inexperienced male rats. Animals were orally administered 100 mg/kg and 500 mg/kg of body weight (b.w) of either the aqueous or the hexane extracts of Mondia whitei whilst the control group received 10 mL/kg b.w of 0.3% Tween 80 once/day for 14 days. Their sexual behaviour was monitored on days 0, 1, 7 and 14 days of treatment and 14 days post-treatment. Some fertility parameters (index libido, quantal pregnancy, fertility index) of the treated rat were evaluated on day 13 of treatment by pairing it overnight with two proestrus females. Results showed that Mondia whitei extracts significantly (p<0.001) reduced the mount latency and the hexane extract was found to be more efficient than the aqueous extract. The treatment had no significant effect (p>0.05) on intromission, ejaculation and erection. The fertility of the animals remained unaffected. It's concluded that Mondia whitei had sexual enhancement of the sexually inexperienced male rats.
Jean Jules Bankeu Kezetas, Bruno Ndjakou Lenta, Silvère Augustin Ngouela, Etienne Tsamo, Norbert Sewald, Beate Neumann and 1 more
Acta Crystallographica Section E Structure Reports Online
The title compound, C20H16O5, also known as 5,7-dihyroxy-3-(2′,2′-dimethyl-2H'-chromen-7′-yl)chroman-4-one, was isolated from the medicinal plant Ficus mucuso. The benzopyranone (chromen-4-one) ring system is essentially planar and the dihedral angle between the benzopyranone ring system and the other benzene ring is 37.7 (10)°. In the crystal structure, one-dimensional chains are formed via intermolecular O—H⋯O hydrogen bonds.
Didérot Tchamo Noungoué, Bruno Ndjakou Lenta, Annelise Lobstein, Silvère Augustin Ngouela, Etienne Tsamo
Acta Crystallographica Section E Structure Reports Online
The title compound, C30H48O, is a tirucallane triterpenoid which was isolated from the medicinal plant Vismia laurentii. The molecule contains four fused rings, typical of steroids. Ring A adopts a chair conformation, ring B a sofa conformation, ring C a twist conformation and ring D an envelope conformation. The A/B and C/D ring junctions are both trans.
DT Noungoue, Saliou Ngom, Joseph Ngoupayo, Mehdi Chaabi, BL Ndjakou, Silvère Augustin Ngouela and 6 more
Planta Medica
In the framework of our interest in antimalarial natural products from Clusiaceae family [1,2], the apolar extract of the stem bark of Vismia laurentii showed good antimalarial activity (IC 50 =4.6µg/ml). Thus, the isolation of its constituents led to the identification of a new tetracyclic triterpene, (20-ethylnortirucalla-7,24-dien-3-one) vismiaturucallone ( 1 ) (Fig.1) along with eight known compounds namely 3-geranyloxyemodin, vismiaquinone A ( 3 ), vismiaquinone B, bivismiaquinone, epifriedelinol, betulinic acid, tirucalla-7,24-dien-3-one, and stigmasta-7,22-dien-3-ol. Compounds ( 1 ) and ( 3 ) showed antiplasmodial activity against chloroquine-resistant W2 strain of Plasmodium falciparum with IC 50 of 1.17µM and 1.42µM, respectively. Fig.1 References: [1] Ngouela, S. et al. (2005) Nat Prod Res 19(7):685–8. [2] Ngouela, S. et al. (2006) Phytochemistry 67(3):302–6.
Bruno Ndjakou Lenta, Catherine Vonthron‐Sénécheau, R. Fongang Soh, Ferdinand Tantangmo, Silvère Augustin Ngouela, Marcel Kaiser and 3 more
Journal of Ethnopharmacology
Silvère Augustin Ngouela, Bruno Lenta Ndjakou, Diderot Noungoué Tchamo, Fabien Zelefack, Etienne Tsamo, Joseph D. Connolly
Natural Product Research
A prenylated xanthone has been isolated from the seeds of Symphonia globulifera together with the known compounds sitosterol and oleanolic acid. The structure of the new compound was elucidated by spectroscopic methods.
Ddp Chuisseu, F Paul Moundipa, NA Tchana, Fabien Zelefack, Silvère Augustin Ngouela, Etienne Tsamo
Journal of the Cameroon academy of sciences
Silvère Augustin Ngouela, Guy Feuya, Jean Claude Tchouankeu, Gaston Achoundong, Raymond B.T. Zambou, Etienne Tsamo and 1 more
DOAJ (DOAJ: Directory of Open Access Journals)
A new lignan, meiocarpin, and the known compounds, sitosterol and polycarpol, have been isolated from the stem bark of <i>Meiocarpidium lepidotum</i>, Annonaceae. The structure of the new compound was elucidated on the basis of its spectroscopic data.
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