Gabriel Ngosong Folefoc

Design, isolation, synthesis, and mechanistic insight of flavonoids isolated from Beilschmiedia obscura, as potential α-glucosidase inhibitors

Suzanne L. Nyemeck, Kenneth O. Eyong, Ronald à Goufani Bidingha, Michael H. K. Kamdem, Derek Tantoh Ndinteh, Patricia Odumosu and 6 more

Phytochemistry Letters

• #natural antidiabetic agents studies
• #natural product bioactivities and synthesis
• #pharmacological effects of natural compounds
• #isolation (microbiology)

Selective Electrophile‐Promoted Cyclization Reactions of Lapachol and Evaluation of Bioactive Naphthoquinones Against Cancer Cell Lines

Irene Nadage Omdim, Kenneth O. Eyong, Blandine Marlyse Wache Ouahouo, Hervé Landry Ketsemen, Thomas Werner, Michael Hermann Kengne Kamdem and 6 more

Journal of Heterocyclic Chemistry

ABSTRACT Cyclic ether‐fused tricyclic naphthoquinones are major pharmacophores because of their biological activities. The methodology of construction is either by inter or intra‐molecular cyclization of functionalized naphthoquinones. This reaction includes a wide range of reagents from classical Brønsted to Lewis acids. The choice of appropriate reagent and reaction conditions against the substrate is the key to accomplishing the regio‐ and/or stereo‐selective synthesis of these compounds, though it seems difficult at first glance to decide how because numerous numbers of actual examples have been presented. To have a deeper insight into the mechanism of cyclization under acid conditions, lapachol 1 was subjected to electrophilic entities: Brønsted acids (H 2 SO 4 , HCl, H 3 PO 4 , HNO 3 , HCOOH, CH 3 COOH, HOOCCH 2 COOH), Lewis acids (AlCl 3 , FeCl 3 , ZnCl 2 ) nitrogenous cations (NO + , NO 2+ ), carbocation (CH 3 CO + ), neutral polarized molecules (CH 3 COCl, CH 3 COOCH 3 ), neutral polarizable molecules (Br 2 , I 2 ), oxidant promoted cyclization (DDQ, CAN, Peroxides), and reaction conditions. A series of Naphthoquinones based on the Isoprenyl‐1,4‐naphthoquinone (Lapachol), naphtho[1,2‐b]furan‐4,5‐dione (nor β‐lapachone), naphtho[2,3‐b]pyran‐5,10‐dione (α‐lapachone), naphtho[1,2‐b]pyran‐5,6‐dione (β‐lapachone), and naphtho[2,3‐b]furan‐4,9‐dione (2‐acetyl furonaphthoquinone) skeletons were selectively synthesized. By looking at our result, there are characteristic trends of cyclized adducts depending on which reagents were used. The synthesized compounds were evaluated for their biological activity against the MDA‐MB‐231 breast cancer, HT‐29 MTX colon cancer, and non‐transformed mammary epithelial cell lines at concentrations of 1 μM, 10 μM, and 100 μM. The result indicated that lapachol and β‐lapachone skeletons were the most active at 10 μM and 100 μM especially 3‐hydroxy‐β‐lapachone 8 with interesting growth stimulatory effect on cancer cell lines, but not the non‐transformed cells.

• #bioactive compounds and antitumor agents
• #synthesis and reactions of organic compounds
• #synthesis of indole derivatives
• #chemistry

Constituents from Psorospermum guineense twigs, MDA-MB-231, lipoxygenase, antioxidant and Molecular Docking Studies

Kenneth O. Eyong, Salome Y. Ghansenyuy, Pierre Yemback, L. Mehreen, Gabriel N. Folefoc

Pakistan Journal of Chemistry

Cancer is one of the leading causes of mortality worldwide, characterized by the irregular proliferation of malignant cells and increasing resistance to known drugs. The importance of developing new chemotherapeutic agents is necessary. The present study focuses on Psorospermum guineense, used in traditional medicine to treat cancer, and associated carcinogenic processes such as tumour cell proliferation, differentiation, and apoptosis. A study of the chemical constituents of the twigs of Psorospermum guineense has resulted in the isolation and characterization of eight known compounds, namely: 3-geranyloxyemodine 1, 3--fridelanol 2, 3-geranyloxyemodine anthrone 3, 2geranylemodine 4, Acetylvismione D 5, Betulinic acid 6, Ursolic acid 7 and Emodine 8 through LC-MS and selected 1D and 2D-NMR experiments. Single crystal x-ray diffraction analysis was used to confirm the relative configuration and conformation of compound 1. Preliminary cytotoxicity assays against the MDA-MB-231 breast cancer cell indicated that Ursolic acid 7 was the most active, with an IC50 value of 9.88 M and 95% CI of 9.03-10.5 M. Acetylvismione D 5 exhibited better lipoxygenase inhibitory activity (19.80.16) and antioxidant activity (20.80.15) compared to the reference drugs baicalein (22.6 0.08 M) and Beta hydroxyl acid (BHA) (44.2 0.07) respectively. Molecular docking studies were conducted to support lipoxygenase inhibitory activities of the test compounds.

• #mangiferin and mango extracts
• #phytochemistry and bioactive compounds
• #chemistry
• #antioxidant

Antiplasmodial and cytotoxic activity of lanostane type triterpenoids isolated from Leplaea mayombensis

Lazare Sidjui Sidjui, Désiré Soh, Gaëtan Herbette, Rufin Marie Kouipou Toghueo, Gabriel N. Folefoc, Valérie Mahiou-Leddet and 2 more

Phytochemistry Letters

• #ethnobotanical and medicinal plants studies
• #essential oils and antimicrobial activity
• #plant biochemistry and biosynthesis
• #lanostane

Glyceraldehyde-3-phosphate dehydrogenase (PfGAPDH): Design, Isolation, Synthesis and preliminary anti-malarial activity against Plasmodium falciparum 3D7 strains.

Yemback Kenneth Pierre, Eyong Kenneth Oben, Noella Molisa Efange, Michael H. K. Kamdem, Derek Tantoh Ndinteh, Patricia Odumosu and 3 more

Research Square

Abstract Glyceraldehyde-3-phosphate dehydrogenase (P f GAPDH) for Plasmodium falciparum is a key glycolytic enzyme that catalyzes the conversion of glyceraldehyde 3-phosphate (G3P) into 1,3-bisphosphate glycerate (1,3-BPG), with the concomitant reduction of nicotinamide adenine dinucleotide (NAD + ) to NADH. Compounds from the Cameroon Natural Product Library (CANAPL), were screened by molecular docking studies against the enzyme target P f GAPDH. Amongst these docking hits were the lupeol cinnamate (1) and oleanane cinnamate (2) with binding energies (E b ) of -10.55 kcal/mol and − 10.51 kcal/mol respectively, compared to P f GAPDH inhibitors; heptelidic acid (-6.47 kcal/mol), iodoacetate (-3.98 kcal/mol) and pentalenolactone (-6.87 kcal/mol). To validate the docking results, triterpenoids with structural similarities to (1) and (2) were isolated from Baillonella toxisperma (Pierre); olean-12-en-3β-hexadecanoate (3), 3-β-trans cinnamoyloxylup-20(29)-ene (4), oleanoic acid benzoate (5), 3β-amyrin (6), taraxerol (7), betulonic acid (8), β-sitosterol (9), betulinic acid (10), 3β-(trans-p-Coumaroyl)oxylup-20(29)-en-28-oïc acid (11), and screened alongside Betuline (12) and oleanolic acid (13). The favorable compounds 8 and 11 with 100% growth inhibition on Plasmodium falciparum 3D7 strains together with compounds 4, 10 and 12 were structurally optimized to afford new lupane derivatives with the privilege α-β unsaturated carbonyl medicinal scaffolds; - betulonic acid acryl aldehyde (14 ) , betulin acryl aldehyde (15), 3β-( trans-p -Coumaroyl)oxylup-20(29)-en-28-oïc acid acryl aldehyde (16), 30-hydroxy betulinic acid (17), betulinic acid acryl aldehyde (18) and 3-β- trans cinnamoyloxylup-20(29)-ene acryl aldehyde (19) exhibiting more potent anti-malarial activities. Their assays afforded IC 50 values of 0.703 µM, 2.15 µM, 1.28 µM, and 3.79 µM for compounds 14, 15, 16 and 18 respectively. These results validate our docking scores and indicate that the modified compounds with the privilege α,β- unsaturated carbonyl medicinal scaffolds could be further optimized into potent antimalarial agents.

• #natural product bioactivities and synthesis
• #glycosylation and glycoproteins research
• #plant biochemistry and biosynthesis
• #betulinic acid

Antiproliferative activity of naphthoquinones and indane carboxylic acids from lapachol against a panel of human cancer cell lines

Kenneth O. Eyong, Hervé Landry Ketsemen, Zhenze Zhao, Liqin Du, Aude Ingels, Véronique Mathieu and 5 more

Medicinal Chemistry Research

• #bioactive compounds and antitumor agents
• #cancer therapeutics and mechanisms
• #chemistry
• #naphthoquinone

Trypanocidal and leishmanicidal activity of six limonoids

Dietmar Steverding, Lazare Sidjui Sidjui, Éden Ramalho Ferreira, Bathélémy Ngameni, Gabriel N. Folefoc, Valérie Mahiou-Leddet and 4 more

Journal of Natural Medicines

Abstract Six limonoids [kotschyienone A and B ( 1 , 2 ), 7-deacetylgedunin ( 3 ), 7-deacetyl-7-oxogedunin ( 4 ), andirobin ( 5 ) and methyl angolensate ( 6 )] were investigated for their trypanocidal and leishmanicidal activities using bloodstream forms of Trypanosoma brucei and promastigotes of Leishmania major . Whereas all compounds showed anti-trypanosomal activity, only compounds 1–4 displayed anti-leishmanial activity. The 50% growth inhibition (GI 50 ) values for the trypanocidal and leishmanicidal activity of the compounds ranged between 2.5 and 14.9 μM. Kotschyienone A ( 1 ) was found to be the most active compound with a minimal inhibition concentration (MIC) value of 10 μM and GI 50 values between 2.5 and 2.9 μM. Only compounds 1 and 3 showed moderate cytotoxicity against HL-60 cells with MIC and GI 50 values of 100 μM and 31.5–46.2 μM, respectively. Compound 1 was also found to show activity against intracellular amastigotes of L. major with a GI 50 value of 1.5 μM. The results suggest that limonoids have potential as drug candidates for the development of new treatments against trypanosomiasis and leishmaniasis.

• #phytochemical compounds biological activities
• #research on leishmaniasis studies
• #insect pest control strategies
• #amastigote

Green Synthesis and Antibacterial Activity of Gold Nanoparticles Using Methanolic Stem Back Extract of Leplaea mayombensis

Lazare Sidjui Sidjui, M. Ponnanikajamideen, M. Malini, M. T. A. Ottou, G. Annadurai, Gabriel N. Folefoc

Journal of Bionanoscience

• #pharmacology and nanomedicine research
• #nanoparticles: synthesis and applications
• #medicinal plants and neuroprotection
• #colloidal gold

Bioactive Seco-Lanostane-Type Triterpenoids from the Roots of Leplaea mayombensis

Lazare Sidjui Sidjui, Kenneth O. Eyong, Kenneth G. Hull, Gabriel N. Folefoc, Valérie M. Leddet, Gaëtan Herbette and 4 more

Journal of Natural Products

Fractionation of the ethyl acetate-soluble extract of the roots of Leplaea mayombensis afforded two new 3,4-seco-lanostane-type triterpenoids, leplaeric acids A and B ( 1, 2 ), the new lanostane-type triterpenoid leplaeric acid C ( 3 ), and six known natural products ( 5 – 10 ). Derivatization of the main constituent, 1, afforded the dimethyl ester 4, the monoamide 11, and diamide 12 for SAR studies. The structures of these compounds were established through spectroscopic methods, and a single-crystal X-ray diffraction analysis was used to confirm the relative configuration of compound 1 . These lanostane derivatives are unique since they are the first C-21-oxygenated lanostanes isolated from plant sources. Preliminary biological assays against the MDA MB 231 breast cancer cell line showed that compounds 1, 2, 4, and 11 have modest cytotoxic activity. Compound 2 was the most active, with an IC 50 of 55 ± 7 μM. From these results, the amides ( 11, 12 ) derived from triterpenoid 1 were found to be less active than the derived esters ( 2, 4 ).

• #natural product bioactivities and synthesis
• #biological activity of diterpenoids and biflavonoids
• #plant biochemistry and biosynthesis
• #lanostane

Antiplasmodial and Cytotoxic Activities of Extracts from Jacaranda mimosifolia and Pseudospondias microcarpa

Lazare Sidjui Sidjui, Rufin Marie Kouipou Toghueo, Valérie Mahiou-Leddet, Sébastien Hutter, Évelyne Ollivier, Gabriel N. Folefoc

HAL (Le Centre pour la Communication Scientifique Directe)

International audience

• #phytochemistry medicinal plant applications
• #cytotoxic t cell
• #biology
• #traditional medicine

A new ursane triterpenoic acid and other potential anti-inflammatory and anti-arthritic constituents from EtOAc extracts of Vitellaria paradoxa stem bark

Kenneth O. Eyong, Harquin Simplice Foyet, Guerisson Baïrys, Gabriel N. Folefoc, Emanuel Acha Asongalem, Andreas Lagojda and 1 more

Journal of Ethnopharmacology

• #phytochemical compounds biological activities
• #natural product bioactivities and synthesis
• #ginger and zingiberaceae research
• #traditional medicine

Antibacterial Activity of the Crude Extracts, Fractions and Compounds from the Stem Barks of Jacaranda mimosifolia and Kigelia africana (Bignoniaceae)

Lazare Sidjui Sidjui, Rufin Marie Kouipou Toghueo, Elisabeth Menkem Zeu, Cedric Derick Jiatsa Mbouna, Valérie M. Leddet, Gaëtan Herbette and 3 more

Pharmacologia

Background: Plants of the genus Jacaranda and Kigelia (Bignoniaceae) are traditionally used to relieve ear infection, abscesses, ulcers, diarrhea, dysentery, boils, fungal infections, psoriasis and eczema. The main objective was to undergone the phytochemical investigation and antibacterial activity of the stem barks of Jacaranda mimosifolia and Kigelia africana. Materials and Methods: Plants were extracted by solvents of various polarities. Compounds isolation was carried out using chromatography methods (medium and high-pressure liquid chromatography, open column and thin-layer chromatography). The isolated compounds were identified and characterized by using 1D and 2D NMR spectroscopy. The antimicrobial activity was assayed against some Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa and Salmonella typhi) and Gram-positive bacteria (Staphylococcus aureus) by determining the Minimum Inhibitory Concentration (MIC). Results: The phytochemical investigation of Jacaranda mimosifolia and Kigelia africana led to the isolation of seventeen known compounds, seven terpenoid, four quinone and seven order compounds. The extracts and pure compounds exhibited antibacterial activities with inhibition zone diameters ranging from 0.00.0 to 11.00.2 mm. Selected crude extracts, fractions and compounds showed Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) ranging from 0.10.0 to >0.830.00 and 0.830.00 to >0.830.00 mg mLG 1 , respectively, against the tested microorganisms. Compound 17showed the best MIC against the four strains. Conclusion: The results obtained indicate that these plants could be a possible source of an effective antibacterial and justify the traditional uses.

• #phytochemistry medicinal plant applications
• #psidium guajava extracts and applications
• #ethnobotanical and medicinal plants studies
• #bignoniaceae

Antiyeast Activity of Methanolic Extracts and Compounds from Jacaranda mimosifolia (D.) Don and Kigelia africana (Lam.) Benth

Yves Oscar, D. Nganso, Elisabeth M. Zeuko, Fabrice Fekam Boyom, Gabriel N. Folefoc

The aim of this study was to evaluate the anticandidal activity of fruit, root, stem bark extracts and compounds from Jacaranda mimosifolia and Kigelia africana (Bignoniaceae) on four Candida albicans strains ATCCL26, ATCC12C, ATCCP37039, and ATCCP37037. The extracts from different plants part were prepared using Methanol and Methanol/Methylene Chloride. Column chromatography was used for the fractionation and isolation of compounds. Agar disc diffusion method was used to screen anticandidal activity of the extracts and compounds. Micro dilution method was used to determine the Minimum Inhibitory Concentration of the selected extracts/compounds. The compounds Benzoic acid 1, 5-carboxy-1,2,3,4,4a,7,8,8a-octahydro-1,2,4a-trimethyl-, [1S-(1α,2β,4aβ,8aα)] 2, betulinic acid 3, and ursolic acid 5 were obtained from Jacaranda mimosifolia. Also, 2-(4-hydroxyphenyl) ethyl ester 11, oleanolic acid 14, β-friedelinol 15 and pomolic acid 16 were obtained from Kigelia africana. The inhibition zone diameters varied from 0 to 10 mm on the four tested C. albicans strains. The Minimum Inhibitory Concentration ranged from 2.045 to ≥ 8.3 mg/mL. The compounds showed better activity than the extracts. The results of this study suggest that the medicinal plants represent an untapped source of compounds with anti-C. albicans activity that could be a resource in the development of new therapeutic natural products.

• #psidium guajava extracts and applications
• #phytochemistry medicinal plant applications
• #natural product bioactivities and synthesis
• #bignoniaceae

Chemical constituents, the stereochemistry of 3-hydroxy furonaphthoquinones from the root bark of Newbouldia laevis Seem (Bignoniaceae), and screening against Onchocerca ochengi parasites

Kenneth O. Eyong, Hervé Landry Ketsemen, Salome Y. Ghansenyuy, Gabriel N. Folefoc

Medicinal Chemistry Research

• #bioactive compounds and antitumor agents
• #phytochemical compounds biological activities
• #morinda citrifolia extract uses
• #bignoniaceae

CCDC 897940: Experimental Crystal Structure Determination

Kenneth O. Eyong, M. Puppala, P. Senthil Kumar, Marc Lamshöft, Gabriel N. Folefoc, Michael Spiteller 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.

• #crystallization and solubility studies
• #x-ray diffraction in crystallography
• #crystallography
• #crystal structure

A mechanistic study on the Hooker oxidation: synthesis of novel indanecarboxylic acid derivatives from lapachol

Kenneth O. Eyong, Manohar Puppala, Ponminor Senthil Kumar, Marc Lamshöft, Gabriel N. Folefoc, Michael Spiteller and 1 more

Organic & Biomolecular Chemistry

The Hooker oxidation is one of the most intriguing transformations wherein lapachol (1) is readily converted to norlapachol (2) in very good yield. This one-pot reaction involves a very intricate mechanism in which the alkyl side chain of lapachol is shortened by one carbon unit. Previous studies have unequivocally established the involvement of an indane carboxylic acid derivative 3, as a key intermediate (Hooker intermediate), and its simultaneous conversion to norlapachol (2) via the oxidative cleavage of vicinol diol and subsequent intramolecular aldol reaction of the resulting keto acid. However, the formation of the key Hooker intermediate 3 from lapachol (1) remains ambiguous. The present study has thrown some light on the formation of the key intermediate 3 from lapachol (1) via benzilic acid rearrangement of the corresponding labile o-diquinone intermediate 8 derived from lapachol. The involvement of o-diquinone intermediate 8 in the Hooker oxidation has been further established by trapping of this labile intermediate as the corresponding phenazine derivative 9. The involvement of benzilic acid rearrangement as a key step in the Hooker oxidation is further shown with a variety of o-quinones prepared from lapachol (1).

• #bioactive compounds and antitumor agents
• #oxidative organic chemistry reactions
• #marine sponges and natural products
• #chemistry

Anticancer Activities of Six Selected Natural Compounds of Some Cameroonian Medicinal Plants

Victor Kuete, Hippolyte K. Wabo, Kenneth O. Eyong, Michel T. Feussi, Benjamin Wiench, Benjamin Krusche and 3 more

PLoS ONE

BACKGROUND: Natural products are well recognized as sources of drugs in several human ailments. In the present work, we carried out a preliminary screening of six natural compounds, xanthone V(1) (1); 2-acetylfuro-1,4-naphthoquinone (2); physcion (3); bisvismiaquinone (4); vismiaquinone (5); 1,8-dihydroxy-3-geranyloxy-6-methylanthraquinone (6) against MiaPaCa-2 pancreatic and CCRF-CEM leukemia cells and their multidrug-resistant subline, CEM/ADR5000. Compounds 1 and 2 were then tested in several other cancer cells and their possible mode of action were investigated. METHODOLOGY/FINDINGS: The tested compounds were previously isolated from the Cameroonian medicinal plants Vismia laurentii (1, 3, 4, 5 and 6) and Newbouldia laevis (2). The preliminary cytotoxicity results allowed the selection of xanthone V(1) and 2-acetylfuro-1,4-naphthoquinone, which were then tested on a panel of cancer cell lines. The study was also extended to the analysis of cell cycle distribution, apoptosis induction, caspase 3/7 activation and the anti-angiogenic properties of xanthone V(1) and 2-acetylfuro-1,4-naphthoquinone. IC(50) values around or below 4 µg/ml were obtained on 64.29% and 78.57% of the tested cancer cell lines for xanthone V(1) and 2-acetylfuro-1,4-naphthoquinone, respectively. The most sensitive cell lines (IC(50)<1 µg/ml) were breast MCF-7 (to xanthone V(1)), cervix HeLa and Caski (to xanthone V(1) and 2-acetylfuro-1,4-naphthoquinone), leukemia PF-382 and melanoma colo-38 (to 2-acetylfuro-1,4-naphthoquinone). The two compounds showed respectively, 65.8% and 59.6% inhibition of the growth of blood capillaries on the chorioallantoic membrane of quail eggs in the anti-angiogenic assay. Upon treatment with two fold IC(50) and after 72 h, the two compounds induced cell cycle arrest in S-phase, and also significant apoptosis in CCRF-CEM leukemia cells. Caspase 3/7 was activated by xanthone V(1). CONCLUSIONS/SIGNIFICANCE: The overall results of the present study provided evidence for the cytotoxicity of compounds xanthone V(1) and 2-acetylfuro-1,4-naphthoquinone, and bring supportive data for future investigations that will lead to their use in cancer therapy.

• #natural compound pharmacology studies
• #bioactive compounds and antitumor agents
• #morinda citrifolia extract uses
• #xanthone

Antibacterial activity of some natural products against bacteria expressing a multidrug-resistant phenotype

Victor Kuete, Sandrine Alibert, Kenneth O. Eyong, Bathélémy Ngameni, Gabriel N. Folefoc, Jean Robert Nguemeving and 9 more

International Journal of Antimicrobial Agents

• #microbial natural products and biosynthesis
• #antibiotic resistance in bacteria
• #essential oils and antimicrobial activity
• #bacteria

CCDC 669085: Experimental Crystal Structure Determination

Kenneth O. Eyong, Prashant Kumar, Victor Kuete, Gabriel N. Folefoc, Ephriam A. Nkengfack, S. Baskaran

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.

• #crystallization and solubility studies
• #x-ray diffraction in crystallography
• #crystal structure
• #crystallography

CCDC 669086: Experimental Crystal Structure Determination

Kenneth O. Eyong, P. Senthil Kumar, Victor Kuete, Gabriel N. Folefoc, Ephriam A. Nkengfack, S. Baskaran

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.

• #crystallization and solubility studies
• #x-ray diffraction in crystallography
• #crystallography
• #crystal structure

Chemical constituents of Dorstenia picta and Newbouldia laevis

Bertin Vouffo, Hidayat Hussain, Kenneth O. Eyong, Étienne Dongo, Gabriel N. Folefoc, Augustin E. Nkengfack and 1 more

Biochemical Systematics and Ecology

• #natural product bioactivities and synthesis
• #phytochemistry and biological activities
• #bioactive natural compounds
• #biology

Semisynthesis and antitumoral activity of 2-acetylfuranonaphthoquinone and other naphthoquinone derivatives from lapachol

Kenneth O. Eyong, Ponminor Senthil Kumar, Victor Kuete, Gabriel N. Folefoc, Ephriam A. Nkengfack, Sundarababu Baskaran

Bioorganic & Medicinal Chemistry Letters

• #bioactive compounds and antitumor agents
• #synthesis of organic compounds
• #cancer therapeutics and mechanisms
• #chemistry

Maternal and developmental toxicity evaluation of Acanthus montanus leaves extract administered orally to Wistar pregnant rats during organogenesis

Paulin Nana, Emmanuel Acha Asongalem, Harquin Simplice Foyet, Gabriel N. Folefoc, T Dimo, Pièrre Kamtchouing

Journal of Ethnopharmacology

• #birth, development, and health
• #fatty acid research and health
• #organogenesis
• #toxicity

Newbouldiaquinone A: A naphthoquinone–anthraquinone ether coupled pigment, as a potential antimicrobial and antimalarial agent from Newbouldia laevis

Kenneth O. Eyong, Gabriel N. Folefoc, Victor Kuete, Véronique Penlap Beng, Karsten Krohn, Hidayat Hussain and 4 more

Phytochemistry

• #bioactive compounds and antitumor agents
• #morinda citrifolia extract uses
• #marine sponges and natural products
• #naphthoquinone

Newbouldiaquinone A: A Naphthoquinone—Anthraquinone Ether Coupled Pigment, as a Potential Antimicrobial and Antimalarial Agent from Newbouldia laevis.

Kenneth O. Eyong, Gabriel N. Folefoc, Victor Kuete, Véronique Penlap Beng, Karsten Krohn, Hidayat Hussain and 4 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.

• #bioactive compounds and antitumor agents
• #morinda citrifolia extract uses
• #phytochemistry and bioactivity studies
• #chemistry

Constituents from the roots of Pentaclethra macrophylla

Gabriel N. Folefoc, Jean Paul Bisseck, Zacharias Tanee Fomum, Bernard Bodo

Biochemical Systematics and Ecology

• #phytochemistry and bioactivity studies
• #phytochemistry and biological activities
• #natural product bioactivities and synthesis
• #biology

Newbouldiaquinone and Newbouldiamide: A New Naphthoquinone-Anthraquinone Coupled Pigment and a New Ceramide from Newbouldia laevis

Kenneth O. Eyong, Karsten Krohn, Hidayat Hussain, Gabriel N. Folefoc, Augustin Ephram Nkengfack, Barbara Schulz and 1 more

Chemical and Pharmaceutical Bulletin

Newbouldiaquinone (1), a new naphthoquinone-anthraquinone coupled pigment and a new ceramide named newbouldiamide (2), have been isolated from Newbouldia laevis, besides the known compounds lapachol (3), canthic acid, oleanolic acid, 2-methyl-9,10-anthracenedione, 2-acetylfuro-1,4-naphthoquinone, 2,3-dimethoxy-1,4-benzoquinone, 2-(4-hydroxyphenyl)ethyl triacontanoate, beta-sitosterol and beta-sitosterol glucopyranoside. The structure elucidations of the isolated new compounds were performed on the basis of spectroscopic and chemical evidence. Preliminary studies showed that 1 is moderately antibacterial against Gram-positive Bacillus megaterium and that 3 has moderate herbicidal and antibacterial activities.

• #bioactive compounds and antitumor agents
• #morinda citrifolia extract uses
• #marine sponges and natural products
• #chemistry

Analgesic and antiinflammatory activities of Erigeron floribundus

Emmanuel Acha Asongalem, Harquin Simplice Foyet, J Ngogang, Gabriel N. Folefoc, Théophile Dimo, Pièrre Kamtchouing

Journal of Ethnopharmacology

• #sesquiterpenes and asteraceae studies
• #phytochemistry and biological activities
• #herbal medicine research studies
• #analgesic

Diprenylated chalcones and other constituents from the twigs of Dorstenia barteri var. subtriangularis

Barthélémy Ngameni, Bonaventure T. Ngadjui, Gabriel N. Folefoc, Jean Watchueng, Berhanu M. Abegaz

Phytochemistry

• #natural product bioactivities and synthesis
• #phytochemistry and biological activities
• #sesquiterpenes and asteraceae studies
• #moraceae

Heterocycles of biological importance: Part 6. The formation of novel biologically active pyrimido[1,2-a]benzimidazoles from electron deficient alkynes and 2-aminobenzimidazoles

Helene Wahe, Peter F. Asobo, R. А. Cherkasov, Augustin E. Nkengfack, Gabriel N. Folefoc, Zacharias T. Fomum and 1 more

ARKIVOC

2-Aminobenzimidazole (1a) and its 5,6-dimethyl derivative 1b react with phenylpropynenitrile (2) to give 2-amino-4-phenylpyrimido[1,2-a]benzimidazoles 8a,b in excellent yields. Of these compounds, 2-amino-7,8-dimethyl-4-phenylpyrimido[1,2-a]benzimidazole (8b) has been shown to possess diuretic properties. Acetylenic aldehydes 9a,b also react with 1a,b to give pyrimido[1,2-a]benzimidazoles 13a-13d in good yield.

• #synthesis and characterization of heterocyclic compounds
• #synthesis and biological activity
• #synthesis and biological evaluation
• #chemistry

Diterpenoids from the stem bark of Croton zambesicus

Bonaventure T. Ngadjui, Berhanu Abegaz, Félix Keumedjio, Gabriel N. Folefoc, Gilbert W.F Kapche

Phytochemistry

• #plant biochemistry and biosynthesis
• #bioactive natural diterpenoids research
• #essential oils and antimicrobial activity
• #lupeol

An isoflavan-quinone and a flavonol from Millettia laurentii1Part 10 in the series “The Millettia of Cameroon”.1

Pierre Kamnaing, Samuel N. Y. Fanso Free, Augustin E. Nkengfack, Gabriel N. Folefoc, Zacharias Tanee Fomum

Phytochemistry

• #bioactive natural compounds
• #biological and pharmacological studies of plants
• #natural product bioactivities and synthesis
• #isoflavones

A highly stereoselective route to substituted bis-tetrahydrofurans from 1,5-dienes.

R. AMOUROUX, Gabriel N. Folefoc, F. CHASTRETTE, M. Chastrette

Tetrahedron Letters

• #asymmetric synthesis and catalysis
• #cyclopropane reaction mechanisms
• #synthetic organic chemistry methods
• #chemistry

ChemInform Abstract: A HIGHLY STEREOSELECTIVE ROUTE TO SUBSTITUTED BISTETRAHYDROFURANS FROM 1,5‐DIENES

R. AMOUROUX, Gabriel N. Folefoc, F. CHASTRETTE, M. Chastrette

ChemInform

• #sulfur-based synthesis techniques
• #radical photochemical reactions
• #organic and inorganic chemical reactions
• #citation