BPA
Chargée de Cours
Scientific activity
Researcher profile
Faculty researcher at the University of Yaoundé I. Grade: Chargée de Cours.
Scientific publications
Irène Alice Folefack, Séfirin Djiogue, Rudig Nikanor Tadah Djikem, Jean GALBA BEPPE, Gael Nanou ALLAH-DOUM, Bertrand Mpoo Barga and 3 more
Next research.
Vanis Slauvers Akago, Marie Alfrede Mvondo, Séfirin Djiogue, Stephen Lacmata Tamekou, Nina-Sonia Messongue Mbollo, Josue Jobin Biba and 7 more
Biochemistry Research International
Polycystic ovary syndrome (PCOS) accelerates ovarian follicular depletion through atresia. This study investigated the therapeutic potential of aqueous (AE) and hydroethanolic (HEE) extracts of Cymbopogon citratus in mitigating PCOS‐induced ovarian damage (specifically ferroptosis, apoptosis, and oxidative stress) in a rat model of PCOS. PCOS was induced by oral administration of letrozole (1 mg/kg/day for 21 days), followed by treatment with AE or HEE (100, 200, or 400 mg/kg/day for 20 days) with metformin (200 mg/kg) as a positive control. The results showed that HEE contains 5 times more alkaloids than AE. In experimental animals, C. citratus corrected ovarian damage caused by PCOS, compared to the disease control treated with distilled water. Indeed, C. citratus decreased serum testosterone levels [maximum decrease rate of 37.10% ( p < 0.0001) obtained with HEE100] and increased estradiol levels [maximum increase rate of 56.15% ( p < 0.0001) obtained with AE200]. An increase in serum ghrelin levels [maximum increase rate of 129.38% ( p < 0.0001) obtained with AE400] and a decrease in leptin levels [maximum decrease rate of 43.85% ( p < 0.0001) obtained with AE400] were observed. In the ovaries, C. citratus decreased Fe 2+ [maximum decrease rate of 31.57% ( p < 0.01) obtained with HEE200], caspase 3 [maximum decrease rate of 24.47% ( p < 0.05) obtained with HEE400], oxidative stress markers [MDA: up to 23.28% decrease ( p < 0.05) induced by AE100], and increased antioxidants [catalase: up to 29.99% increase ( p < 0.05) induced by HEE100 and GSH: up to 42.37% increase ( p < 0.01) induced by HEE200]. C. citratus also decreased cystic and atretic follicles and promoted follicle growth and ovulation. In conclusion, C. citratus extracts are capable of protecting the ovaries from the adverse effects of PCOS, primarily ferroptosis, and apoptosis of follicular cells. Of the two extracts, AE seems ideal due to its low alkaloid content.
Chiara Nange Adjoffoin, Séfirin Djiogue, Emmanuella Regine Mayemi, Florette Motoum Tedjo, Berlise Yengwa Bakam, Benderline Christine Nana and 3 more
Journal of Ethnopharmacology
Adjoffoin Chiara Nange, Séfirin Djiogue, Ambamba Akamba Bruno Dupon, Bakam Yengwa Berlise, Kevine Kamga Silihe, Dieudonné Njamen
International Journal of Basic & Clinical Pharmacology
Background: Aframomum species are routinely used as spices in many traditional Cameroonian meals due to their sweet fragrance. Many species of the Aframomum species are also used to treat cancer, pain, arthritis, and stomach disorders. This work was performed to determine the chemical composition, antiandrogenic, and estrogenic properties of Aframomum subsericeum and Aframomum alboviolaceum leaf essential oils. Methods: The chemical components of A. subsericeum and A. alboviolaceum essential oils were identified by gas chromatography-mass spectroscopy. The anti-androgenic and estrogenic properties were investigated in vivo in physically and chemically castrated Wistar rats, respectively. Results: Fifteen compounds versus nine compounds were identified in A. subsericeum and A. alboviolaceum essential oils, respectively. The main compounds of Aframomum subsericeum were cyclohexene, 1-methyl-4-(1-methylethylidene) (10.03%), γ-terpine (12.22%), and myrtenyl acetate (8.52%), while those of Aframomum alboviolaceum were γ-terpinene (20.07%), caryophyllene (11.58%), myrtenyl acetate (7.22%), and (1R)2, 6, 6 trimethylbicyclo [3.1.1] hept-2-ene (6.97%). The results of the anti-androgenic test reveal that both A. subsericeum and A. alboviolaceum induced a significant decrease in androgen-dependent organs, especially the prostate and seminal vesicle, at doses of 200 mg/kg and 100 mg/kg. Interestingly, A. alboviolaceum showed oestrogen synergic effects on the above organs. Conclusions: So, this study reveals mainly the presence of diterpenoids in both A. subsericeum and A. alboviolaceum, which are potential candidates for prostate cancer treatment. The in vivo results show that Aframomum leaf essential has antiandrogenic and oestrogen synergic properties, suggesting that the oils could provide a safe natural drug for prostate cancer treatment.
Mengue Ngadena Yolande Sandrine, Kavaye Kandeda Antoine, Bilanda Danielle Claude, Yonti Dzueffo Merveille, Atsamo Albert, Owona Pascal Emmanuel and 4 more
Asian Journal of Research in Medical and Pharmaceutical Sciences
Background: Anti-inflammatory and antioxidant activities are the main pathways of neuroprotective drugs. Bridelia atroviridis possesses those activities and is empirically used by Cameroonian traditional healers to alleviate memory and mood disorders. Objective: The purpose of this study is to evaluate the anti-amnesic and antidepressant effects of Bridelia atroviridis aqueous extract (EA). Methods: Scopolamine was used to induce amnesia and depression in rats. Administrated per os, three doses of EA, including 36, 72, and 144 mg/kg, were used. Behavioral disorders were evaluated through novel object recognition, the Morris water maze, forced swimming, and an open arena. The oxidative stress markers, like malondialdehyde, reduced glutathione, and nitrite levels in the brain, were measured. Neurometabolites, serotonin, and acetylcholine levels were determined. Hematoxylin-eosin paraffin-embedded histological sections were used to assess neuron viability in the cortex and the hippocampus. Results: Pre-treatments with EA attenuated the deleterious effects of scopolamine and improved brain biomarkers. Indeed, when compared to vehicle control, Bridelia atroviridis increased Ca2+, Mg2+, serotonin, and acetylcholine levels in the brain. Furthermore, the plant reduced significantly (p < 0.001) the recognition index in the novel object recognition test and increased (p < 0.001) the time spent in the target quadrant in the Morris water maze test. Besides, EA has scavenging activities and attenuates neuron death in the cortex and hippocampus. Conclusion: According to this study, the aqueous extract of B. atroviridis barks protects against scopolamine-induced memory loss and depressive disorders. The preventive activities of the plant involve cholinergic and monoaminergic pathways and antioxidant potential. Graphical Abstract:
Biomedical Journal of Scientific & Technical Research
Background: Tengh is a drink made by several Cameroonian spices including Zingiber officinale, Allium sativum, Cymbopogon citratus, Ocimum basilicum, Petroselinum crispum, and Bee propolis. In Cameroon, the drink is empirically used for the treatment of inflammation, pain and anxiety. In our previous studies, Tengh shows an anti-inflammatory and analgesic activity. Knowing the link between inflammation, oxidative stress and neurodegenerative disorders, the present study aimed to assess neuroprotective effects of Tengh on memory impairment and neuroinflammation induced by Scopolamine on ovariectomized Wistar rat.
Christelle Massop Wamba Ndé, Séfirin Djiogue, Charline Florence Awounfack, Franklin Zemo Gamo, Florette Motoum Tedjo, Rudig Nikanor Djikem Tadah and 1 more
Research Square
Abstract Background: Avocado is a tree’s fruit ( Persea Americana Mill.) of the Laucaceae family. It was reported that consumption of avocado improved cognitive performance. No study has yet been carried out regarding the properties of avocado oil supplementation on the occurrence of Alzheimer's disease. The objective of the present study was to evaluate the effects of extra-virgin avocado oil on a model of D-galactose-induced Alzheimer's disease in ovariectomized Wistar rats. Methods: To accomplish this, 54 female rats were used, of which 42 were ovariectomized (OVX) and 12 underwent white surgery (SHAM). Fourteen days after surgery, the animals were divided into 9 groups of 6 animals each: SHAM+Veh and OVX+Veh groups receiving the vehicle; SHAM + D-gal and OVX+D-gal groups receiving D-galactose and vehicle; OVX+D-gal+E2V and OVX+D-gal+DNPZ groups receiving D-galactose and reference drugs (estradiol valerate and donepezil respectively) and 3 test groups (OVX+D-gal+AO1; OVX+D-gal+AO2 and OVX+D-gal+AO3) receiving D-galactose each and extra-virgin avocado oil at the doses of 0.25, 0.5 and 1 mL/kg respectively. The treatment was carried out during 70 days during which memory disorders were evaluated using the Object Recognition , Y-Maze and MWM tests. Some biochemical parameters regarding memory function were evaluated on hippocampus homogenate 10%. Isolated brain was fixed in 10% formalin for histological analysis. Results: As results, compared to SHAM+Veh group, deterioration of both non-spatial and spatial memory (short- and long-term) was observed in OVX animals threated with D-galactose. In addition, a significant decrease in relative hippocampal weight (p < 0.001), Ach (p < 0.001), Glu (p < 0.001), GSH (p < 0.001), CAT (p < 0.05), and SOD (p < 0.001) activities, and a significant (p < 0.001) increase in Methylglyoxal, MDA, and NO2- . was noted in OVX+D-gal group. Compared to OVX+D-gal group, the treatment with extra-virgin avocado oil at all tested doses reversed or prevented the negative effects induced by ovariectomy and/or by D-galactose on biochemical and oxidative stress biomarkers. The analysis of hippocampus microarchitecture shows that the extra-virgin avocado oil induced a significant decrease (p < 0.05; p < 0.01; p < 0.001) of neuronal loss in CA1 and CA3 hippocampal region. Conclusions: Taken together, these results suggest that avocado oil possesses neuroprotective properties and can be consumed or supplemented to prevent the onset of Alzheimer's disease.
Zemo Gamo Franklin, A. D. Ladagu, Ketcha Wanda Germain Jean Magloire, O. R. Folarin, Séfirin Djiogue, Taidinda Gilbert Tashara and 2 more
Journal of Ethnopharmacology
Etienne Djeuzong, Antoine Kavaye Kandeda, Séfirin Djiogue, Danide Nguedia, Stéphanie Lewale, Florence Tsofack Ngueguim and 2 more
Research Square
<title>Abstract</title> <bold>Background:</bold> Alzheimer's disease is a neurological condition that affects more than 44 million people worldwide. The available treatments target the symptoms rather than underlying causes. <italic>Ziziphus jujuba</italic> (Rhamnaceae) is used in traditional Cameroonian medicine to treat many disorders including memory impairments. The study aimed to evaluate the anti-amnesic and neuroprotective effects of <italic>Z. jujuba</italic> aqueous extract on scopolamine-induced memory disorders in rats. <bold>Methods:</bold> Learning and memory impairments were induced in rats by scopolamine (1mg/kg, i.p.) for 15 days. Rats that developed cognitive impairments were divided as follows: two positive control groups received piracetam (200 mg/kg, <italic>p.o.</italic>) or tacrine (1 mg/kg, <italic>p.o.</italic>); three test groups received the extract (29, 57, and 114 mg/kg, <italic>p.o., </italic>respectively) daily for 15 days. At the end of treatments, memory impairments were assessed by Morris water maze and Y-maze tests. Thereafter, animals were sacrificed and some biochemical parameters (oxidative stress, inflammation, and apoptosis) were estimated in the hippocampus and prefrontal cortex.<bold>Results:</bold> <italic>Z. jujuba</italic> decreased the time to reach the platform and increased the time in the target quadrant. However, it failed to affect spontaneous alternation in the Y-maze. Furthermore, the extract reversed scopolamine-induced oxidative stress, inflammation, and apoptosis. This was confirmed with the prevention of neuronal loss in the hippocampus or prefrontal cortex. <bold>Conclusions:</bold> These findings suggest that <italic>Z. jujuba</italic> extract possesses ant-amnesic and neuroprotective effects. It seems that these effects are mediated in part by antioxidant, anti-inflammatory, and anti-apoptotic activities. This, therefore, justify its use to treat dementia and psychiatric disorders in Cameroon’s folk medicine.
Biomedical Journal of Scientific & Technical Research
Studies carried out on leguminous plants of the genus Pueraria showed that some species of this genus are endowed with oestrogenic properties and are able to relieve some menopausal symptoms. The aim of thiswork was to assess the potential health benefit of Pueraria phaseoloides in ovariectomized rats, an experimental model of menopause. Ovariectomized Wistar rats were treated for 3-days with aqueous (AE) and dichloromethane/methanol (DCM/MeOH) extracts of Pueraria phaseoloides, following the 14-days interval necessary for functionally perceptible oestrogen decline. Oestrogen-like effects were assessed on primary oestrogen target organs, while anxiolytic properties were evaluated with help of the elevated plus-maze (EPM) and the open field (OF) tests. Then, the effects of extracts on hot flushes were evaluated using data loggers. The DCM/MeOH extract (dose 500 mg/kg) significantly increased the uterine epithelial thickness (p < 0.05). Both AE and DCM/MeOH extracts induced the differentiation of the acini, and led to an increase in eosinophilic secretary granules in mammary gland sat all doses tested. Pueraria phaseoloides induced an increase in the percentages of time spent and number of entries in the open arms of the EPM, in the time spent at the centre of the arena in the OF test. The most pronounced anxiolytic effects were induced by AE at the doses 150 and 300 mg/kg. Instead, the DCM/MeOH extract had the strongest oestrogen-like effects and reduced significantly the total number (p < 0.05, p < 0.01), the frequency of hot flushes (at all the doses tested), and their average duration at 300 mg/kg (p < 0.01). Our results suggest that Pueraria phaseoloides has oestrogenic properties and can correct various physiological alterations related to oestrogen depletion in ovariectomized rats, possibly through oestrogenic pathway.
Sylvin Benjamin Ateba, Marie Alfrede Mvondo, Séfirin Djiogue, Stéphane Zingue, Liselotte Krenn, Dieudonné Njamen
Frontiers in Pharmacology
Over the last decade, several studies demonstrated that prenylation of flavonoids enhances various biological activities as compared to the respective nonprenylated compounds. In line with this, the natural prenylated isoflavonoid alpinumisoflavone (AIF) has been explored for a number of biological and pharmacological effects (therapeutic potential). In this review, we summarize the current information on health-promoting properties of AIF. Reported data evidenced that AIF has a multitherapeutic potential with antiosteoporotic, antioxidant and anti-inflammatory, antimicrobial, anticancer, estrogenic and antiestrogenic, antidiabetic, and neuroprotective properties. However, research on these aspects of AIF is not sufficient and needs to be reevaluated using more appropriate methods and methodology. Further series of studies are needed to confirm these pharmacological effects, and this review should lay the basis for the design of respective investigations. Overall, despite the drawbacks of studies recorded, AIF exhibits a potential as drug candidate.
Stéphane Zingue, Harquin Simplice Foyet, Séfirin Djiogue, Yannick Ezo'o Ezo'o, Hervé Hervé Ngatanko Abaïssou, Pafroumi Fachagbo and 1 more
Behavioural Neurology
The present work was undertaken to evaluate the ability of F. umbellata aqueous extract and its major component 7-methoxycoumarin (MC) to improve scopolamine-induced spatial memory impairment in ovariectomized Wistar rats. For this to be done, 10 sham-operated and 30 postmenopausal-like rats were randomly distributed in eight groups (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mi>n</mml:mi><mml:mo>=</mml:mo><mml:mn>5</mml:mn></mml:math>) and treated with distilled water (2 mL/250 g), estradiol valerate (1 mg/kg BW), piracetam (1.5 mg/kg BW), F. umbellata aqueous extract (50 and 200 mg/kg BW), or MC (1 mg/kg BW) for 21 consecutive days. Before and after the memory impairment with scopolamine (2 mg/kg BW), animals underwent behavioral evaluations on Y- and radial mazes. As results, age and ovariectomy did not induce significant changes in the reference memory errors. While age decreased working memory errors, ovariectomy increased it. The MC as well as F. umbellata extract significantly increased (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mi>p</mml:mi><mml:mo><</mml:mo><mml:mn>0.01</mml:mn></mml:math>) the percentage of spontaneous alternation and decreased (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"><mml:mi>p</mml:mi><mml:mo><</mml:mo><mml:mn>0.001</mml:mn></mml:math>) working and spatial reference memory errors and anxiety parameters (rearing and grooming) in ovariectomized rats. MC significantly reduced (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M4"><mml:mi>p</mml:mi><mml:mo><</mml:mo><mml:mn>0.05</mml:mn></mml:math>) the MDA level, but resulted in an increase in GSH level in brain homogenates. These results suggest that MC is endowed with neuroprotective effects and could account for the neuroprotective effects of F. umbellata in rats.
Germain Jean Magloire Ketcha Wanda, Franklin Zemo Gamo, Séfirin Djiogue, Charline Florence Awounfack, Dieudonné Njamen
International Journal of Phytomedicine
<p><em>Khaya anthotheca</em> (Welw.) C.DC (Meliaceae) is a plant used in Cameroon to alleviate vaginal dryness in postmenopausal women and is also known to have anxiolytic properties.This work was designed to evaluate estrogen-like effects of this plant on primary estrogens targets of ovariectomized adult rats, as well as to evaluate its anxiolytic activities in the elevated plus-maze (EPM) test. In the 3-day uterotrophic assay, the extract increased (p &lt; 0.01) the size of the vaginal epithelia and stimulated the acini differentiation of the mammary gland. In the EPM test, the extract increased the percentage of number of entries (p &lt;0.05; p &lt;0.01) and the percentage of time spent (p &lt; 0.05) into open arms.Italso induced a decrease in percentage of number of entries (p &lt; 0.05; p &lt; 0.01) and the percentage of time spent (p &lt; 0.05) into closed arms. The extract also induced an increase of total arms entries (p &lt; 0.05; p &lt; 0.01) and rearing (p &lt; 0.05). Moreover, there was a decrease of defecation and grooming (p &lt; 0.05; p &lt; 0.01). These results suggest that <em>K. anthotheca</em> is endowed with estrogenic and anxiolytic properties, likely due to the presence of some estrogen-like compounds.</p>
Stéphane Zingue, Thomas Michel, Jules Tchatchou, Nde Chantal Beatrice Magne, Evelyn Winter, André Monchot and 6 more
Journal of Ethnopharmacology
Germain Jean Magloire Ketcha Wanda, Séfirin Djiogue, Franklin Zemo Gamo, Steve Guemnang Ngitedem, Dieudonné Njamen
Journal of Ethnopharmacology
Séfirin Djiogue, Mc Jésus Kinyok, Germain Jean Magloire Ketcha Wanda, Franklin Zemo Gamo, Paul F. Seke Etet, Armel Hervé Nwabo Kamdje and 2 more
Journal of Complementary and Integrative Medicine
BACKGROUND: Newtonia griffoniana (Mimosaceae) is a Central African rain forest tree, whose bark extracts are used in Cameroonian folk medicine for the treatment of anxiety and sleep disorders. METHODS: We evaluated the anxiolytic effects of N. griffoniana stem bark methanol extract and its major isolated constituent 2,3,4-trihydroxybutylpentatriacontanoate (newtonoate) on the elevated plus maze. RESULTS: Significant increases in the percentage of entries into open arms were induced by both N. griffoniana extract (100 and 150 mg/kg BW; p<0.01) and newtonoate (doses of 3 and 15 mg/kg BW; p<0.05). Conversely, decreases in the percentage of entries into closed arms were observed at the same doses. In addition, N. griffoniana methanol extract (100 mg/kg) and the isolated newtonoate (30 mg/kg) induced significant (p<0.01 and p<0.05, respectively) increases in the time spent in the open arms, while inducing a decrease in the time spent in the closed arms. Newtonoate treatment also decreased head dipping number at doses of 3 and 15 mg/kg, while N. griffoniana methanol extract induced the same effect at 200 mg/kg. CONCLUSIONS: These results suggest that N. griffoniana bark extract has anxiolytic properties, which justify its use in folk medicine. Such effects are at least partly mediated by newtonoate.
Séfirin Djiogue, Maria Halabalaki, Dieudonné Njamen, Georg Kretzschmar, George Lambrinidis, Josephine Hoepping and 4 more
Planta Medica
Erythrina poeppigiana is a medicinal plant which is widely used in Asia, Latin America, and Africa in traditional remedies for gynecological complications and maladies. In continuation of studies for the discovery of novel phytoestrogens, four erythroidine alkaloids, namely α-erythroidine, β-erythroidine, and their oxo-derivatives 8-oxo-α-erythroidine and 8-oxo-β-erythroidine, were isolated and structurally characterized from the methanolic extract of the stem bark of E. poeppigiana. Due to the high amounts of erythroidines in the extract and considering the widespread utilization of Erythrina preparations in traditional medicine, the exploration of their estrogenic properties was performed. The estrogenicity of the isolated erythroidines was assayed in various estrogen receptor-(ER)-dependent test systems, including receptor binding affinity, cell culture based ER-dependent reporter gene assays, and gene expression studies in cultured cells using reverse transcription polymerase chain reaction techniques. α-Erythroidine and β-erythroidine showed binding affinity values for ERα of 0.015 ± 0.010% and 0.005 ± 0.010%, respectively, whereas only β-erythroidine bound to ERβ (0.006 ± 0.010%). In reporter gene assays, both erythroidines exhibited a significant dose-dependent estrogenic stimulation of ER-dependent reporter gene activity in osteosarcoma cells detectable already at 10 nM. Results were confirmed in the MVLN cells, a bioluminescent variant of MCF-7 breast cancer cells. Further, α-erythroidine and β-erythroidine both induced the enhanced expression of the specific ERα-dependent genes trefoil factor-1 and serum/glucocorticoid regulated kinase 3 in MCF-7 cells, confirming estrogenicity. Additionally, using molecular docking simulations, a potential mode of binding on ERα, is proposed, supporting the experimental evidences. This is the first time that an estrogenic profile is reported for erythroidine alkaloids, potentially a new class of phytoestrogens.
Dieudonné Njamen, Séfirin Djiogue, Stéphane Zingue, Marie Alfrede Mvondo, Benedicta N. Nkeh-Chungag
Journal of Complementary and Integrative Medicine
In developing countries, around 80% of the population still resorts on traditional medicine for their primary health care. Erythrina poeppigiana (Walp.) O.F. Cook, one of these medicinal plants, was found to be particularly rich in isoflavonoids which exhibited, individually, significant estrogenic activity in vitro. The possible combined effects of these bioactive isoflavones, as they are naturally found in the crude extracts of E. poeppigiana, prompted us to assess their in vivo estrogenicity. We first tested the ability of the extracts to transactivate estrogen receptor alpha (ERα) in vitro using U2OS human osteosarcoma cells. We next investigated their effects in vivo in an uterotrophic assay, using ovariectomized rats treated with the extracts at the doses of 50, 100, 200, and 400 mg/kg BW/d orally for 3 days. Finally, we assessed their ability to relieve hot flushes, using data loggers. At the end of treatments, animals were sacrificed, and organs (mammary glands, vagina, and uteri) were collected for histo-morphometric analyses. The methanol extract significantly and dose-dependently transactivated ERα at all tested doses. All extracts induced significant increases of vaginal and uterine epithelial heights. Only the dichloromethane extract could significantly relieve hot flushes as estradiol. These results indicate that E. poeppigiana extracts have estrogen-like effects in vivo, suggesting that its active principles act in synergy when they are taken in combination in the crude extract. These findings, therefore, support the traditional use of E. poeppigiana to alleviate some menopausal problems; our previous phytochemical investigations contribute to the standardization of this phytomedicine.
Séfirin Djiogue, Armel Hervé Nwabo Kamdje, Lorella Vecchio, Maulilio J. Kipanyula, Mohammed Farahna, Yousef H. Aldebasi and 1 more
Endocrine Related Cancer
Insulin, IGF1, and IGF2 are the most studied insulin-like peptides (ILPs). These are evolutionary conserved factors well known as key regulators of energy metabolism and growth, with crucial roles in insulin resistance-related metabolic disorders such as obesity, diseases like type 2 diabetes mellitus, as well as associated immune deregulations. A growing body of evidence suggests that insulin and IGF1 receptors mediate their effects on regulating cell proliferation, differentiation, apoptosis, glucose transport, and energy metabolism by signaling downstream through insulin receptor substrate molecules and thus play a pivotal role in cell fate determination. Despite the emerging evidence from epidemiological studies on the possible relationship between insulin resistance and cancer, our understanding on the cellular and molecular mechanisms that might account for this relationship remains incompletely understood. The involvement of IGFs in carcinogenesis is attributed to their role in linking high energy intake, increased cell proliferation, and suppression of apoptosis to cancer risks, which has been proposed as the key mechanism bridging insulin resistance and cancer. The present review summarizes and discusses evidence highlighting recent advances in our understanding on the role of ILPs as the link between insulin resistance and cancer and between immune deregulation and cancer in obesity, as well as those areas where there remains a paucity of data. It is anticipated that issues discussed in this paper will also recover new therapeutic targets that can assist in diagnostic screening and novel approaches to controlling tumor development.
Dieudonné Njamen, Benedicta N. Nkeh-Chungag, Séfirin Djiogue, Emmanuel Yankep, Erick Marcel Noudji, Jacques Djapou and 2 more
AFRICAN JOURNAL OF BIOTECHNOLOGY
Bridelia grandis is used in most parts of tropical Africa for the treatment of diabetes. The anti-diabetic properties of the methanolic stem bark extract of this plant was studied in ob/ob and db/db mice. The plant extract induced hypoglycaemic effects of long duration in the ob/ob mice, while its effects were less pronounced in the db/db mice. Twenty four hours after the cessation of drug administration, both ob/ob and db/db extract treated animals still had significantly lower fasting blood sugar levels when compared to controls, thus confirming its antidiabetic properties.
Séfirin Djiogue, Dieudonné Njamen, Maria Halabalaki, Georg Kretzschmar, Antje Beyer, Jean Claude Mbanya and 2 more
The Journal of Steroid Biochemistry and Molecular Biology
Séfirin Djiogue, D Njamen, Maria Halabalaki, Gerhard Kretzschmar, Antje Beyer, J Mbanya and 2 more
Planta Medica
In a continuation study aiming to discover novel phytoestrogens, we recently reported the isolation and characterization of novel and known isoflavonoids from Erythrina poeppigiana (Walp.) O.F. Cook. (Fabaceae), among which eight appear to be structurally related to genistein with isoprenyl and/or 7-methoxy substitution. In addition, significant binding affinities for the two isotypes of the estrogen receptor ERα and ERβ were demonstrated [1]. These isoflavones derivatives have been investigated for their estrogenic properties in receptor subtype specific reporter gene assay, with a particular focus on their estrogen receptor alpha and beta (ERα and ERβ) selectivity, and their structure-activity relationships using a bone-derived human osteosarcoma cell line (U2OS cells) stably expressing ERα or transiently expressing ERβ. According to our results, an isoprenyl substitution at position 3? together with a 7-methoxy substitution on the genistein skeleton is associated with a statiscally significant activation of the ERα- and ERβ-dependent reporter gene expression in U2OS cells starting from 0.1 nM; while for genistein itself a statistically significant activation was observable at 1 nM. On the other hand, a double prenylation at position 8 and 3? is associated with an almost complete loss of function on the reporter gene activation in U2OS-ERα, but in ERβ expressing system, the effectiveness remains on a statistically significant level, demonstrating an „exclusive ERβ-selectivity“ in U2OS human osteosarcoma cells. References: 1. Djiogue, S. et al. (2009)J. Nat. Prod. 72 (9): 1603–1607.
Séfirin Djiogue, Maria Halabalaki, Xanthippi Alexi, Dieudonné Njamen, Zacharias Tanee Fomum, Μichael N. Alexis and 1 more
Journal of Natural Products
Five new isoflavones, named 5,4'-dihydroxy-7-methoxy-3'-(3-methylbuten-2-yl)isoflavone (1), 5,2',4'-trihydroxy-7-methoxy-5'-(3-methylbuten-2-yl)isoflavone (2), 5,4'-dihydroxy-7-methoxy-3'-(3-methyl-2-hydroxybuten-3-yl)isoflavone (3), 3'-formyl-5,4'-dihydroxy-7-methoxyisoflavone (4), and 5-hydroxy-3''-hydroxy-2'',2''-dimethyldihydropyrano[5'',6'':3',4']isoflavone (5), as well as six known compounds, wighteone (6), 3'-isoprenylgenistein (7), isolupabigenin (8), alpinumisoflavone (9), erypoegin D (10), and crystacarpin (11), were isolated from Erythrina poeppigiana. The structures of the isolated compounds were elucidated on the basis of chemical and spectroscopic analysis. The affinity of these compounds for the estrogen receptors ERalpha and ERbeta was evaluated using a receptor binding assay. While isoprenyl and dimethylpyrano substituents in ring A reduced the affinity of binding to ERbeta ca. 100-fold compared to genistein, the isoprenyl substituent in ring B was better accommodated, allowing 7 to bind with ca. 10-fold lower affinity than genistein.
Séfirin Djiogue, Maria Halabalaki, D Njamen, Z. Tanee Fomum, AL Skaltsounis
Planta Medica
A large variety of plants from Leguminosae family are traditionally used in Cameroon and most African countries in the treatment of numerous diseases such as postmenopausal and metabolic syndrome [1]. In a continuation study on Leguminosae plants, some specific species originated from Cameroon are under investigation in order to explore their phytochemical composition and evaluate the biological activity of the isolated secondary metabolites. The stem bark of 4 species, Amphimas pterocarpoides (Fabaceae), Albizia adianthifolia (Mimosasea), Hylodendron gabonensis (Caesalpiniaceae) and Erythrina poeppigiana (Fabaceae) were selected to be analysed. Based on the HPLC-PDA profile of the DCM and MeOH extracts of the aforementioned plants, the DCM extract of Erythrina poeppigiane where selected to be investigated firstly. Till now a number of secondary metabolites have been isolated and structurally characterized. Most of them are isoflavones and esters of simple phenolics such as esters of ferrulic acid. [2]. Structural assessment of these compounds was carried out using spectroscopic methods (MS, 1&2D NMR). Among the characterized compounds one prenylated isoflavone, 1 found to be a novel natural product. References: 1. Steenkamp, V., (2003)J. Ethnopharmacol. 86:97–108. 2. Addae-Mensah, I. et al. (1992) Phytochemistry 31:2055–2058.
Rudig Nikanor Tadah Djikem, Zuzana Bačová, Séfirin Djiogue, Tomáš Havránek, Kevine Kamga Silihe, Denisa Mihalj and 2 more
Neuroscience
Christelle Massop Wamba Ndé, Séfirin Djiogue, Franklin Zemo Gamo, Charline Florence Awounfack, Rudig Nikanor Djikem Tadah, Kevine Kamga Silihe and 1 more
Neuroscience
Irène Alice Folefack, Séfirin Djiogue, Galba Jean Beppe, Nanou Gael Allah-Doum, Chiara N. Adjoffoin, Rudig Nikanor Tadah Djikem and 4 more
International Journal of Research in Medical Sciences
Background: Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental condition characterized by deficits in social communication and interaction, alongside restricted or repetitive behaviours. This study investigates the potential of hydroethanolic extract of Crassocephalum crepidioides (HEE) to ameliorate ASD-related behaviours in a valproic acid (VPA)-induced mouse model of in utero ASD. VPA exposure disrupts neurodevelopmental processes, affecting synaptic function and neural connectivity which are also seen in Autism. Methods: Thirty pregnant female mice were used among which, six served as normal control group. the twenty-four remaining mice received valproic acid 600 mg/kg on gestational day 10 to day 12. Following parturition, offspring were treated daily from postnatal day 21 to 50. Behavioural assessments were conducted during the treatment period. Upon completion of behavioural testing, brains were collected for biochemical analysis of monoamine levels. Results: Compared to the VPA-exposed control group, HEE treatment at all tested doses significantly reduced (p<0.001) the time spent investigating an empty chamber in a social preference test, and significantly increased (p<0.001) the time spent interacting with a social stimulus (sentinel). Furthermore, HEE treatment significantly increased (p<0.001) brain tissue concentrations of monoamines. Conclusions: These findings suggest that Crassocephalum crepidioides extract may exert neuroprotective effects, improving both social behaviour and reducing repetitive behaviours in this VPA-induced mouse model of ASD. HEE has therapeutic potential by modulating neurotransmitter systems known to be disrupted in Autism.
Zemo Gamo Franklin, Séfirin Djiogue, Mengue Ngadena Yolande Sandrine, Charline Florence Awounfack, Rudig Nikanor Djikem Tadah, Constant Anatole Pieme and 1 more
Exploration of Drug Science
Aim: Menopausal women are suffering from stress-related disorders, and in the previous studies, Khaya anthotheca (K. anthotheca) decoction exhibited estrogenic and anxiolytic properties. Taken together, the aim of this study was to evaluate the effects of K. anthotheca decoction on behavioral disorders and oxidative stress induced by repeated variable stress in ovariectomized Wistar rats. Methods: Forty-two female Wistar rats (10–12 weeks old; 145 ± 10 g) were used. They were ovariectomized (except those from the sham operated group). Fourteen days after ovariectomy, animals were randomly distributed into 7 groups (n = 6): sham operated and negative control groups receiving distilled water; two positive control groups receiving estradiol valerate and diazepam (1 mg/kg each), and three other groups receiving the tested doses of K. anthotheca extract (125, 250, and 500 mg/kg each). The treatment was applied every week. Anxiety, depression, and motor coordination were assessed throughout the experimental procedure. The anti-oxidative potential of the extract was evaluated in rat brain homogenate. Results: It was noted that K. anthotheca extract induced anxiolytic effects marked by an increase in the locomotory activity during open field, light/dark, and elevated plus maze tests. Besides, its anti-depressive effects were shown by a significant (p < 0.05) decrease in the immobilization time during the forced swimming test. By improving the suspension time during grid and wire grip tests, the distance covered, and the number of switch directions during the beam walking test, the extract increased motor coordination. The antioxidant potential of the extract was marked by a significant decrease (p < 0.01) in malondialdehyde level and an increase (p < 0.05) in reduced glutathione level. Conclusions: These results provide valuable insights into the potential therapeutic application of the K. anthotheca extract; however, more studies are needed to elucidate mechanisms of action.
Perpetue Mbede Atsama, Séfirin Djiogue, Charline Florence Awounfack, Dieudonné Njamen
Reproduction and Fertility
Abstract: Current treatments for endometriosis are unsuitable for women who wish to conceive. To verify the supposed beneficial effects of Graptophyllum pictum (G. pictum) on reproductive diseases and inflammation, endometriosis was induced in female Wistar rats using a slightly modified protocol. After verification of successful transplantation (42 days), the animals were co-treated for 7 days with estradiol valerate (E2V; 0.5 mg/kg and the aqueous (GPC) or methanolic (GPM) extracts of G. pictum at doses of 50 and 275 mg/kg. Positive controls received aspirin (3 mg/kg) or letrozole (10 mg/kg). Normal and negative controls received vehicle (distilled water, 10 mL/kg). On day 7, animals were injected with oxytocin 30 min before sacrifice to evaluate some dysmenorrhea-like model parameters. Five animals per group were then sacrificed, and the remaining five animals were mated with males of proven fertility for 25 days. G. pictum extracts at all doses significantly (P < 0.001) increased the time of writhing latency and decreased its frequency and the volume of implant (P < 0.05) at the GPM 50 mg/kg dose. Levels of interleukin-6, tumor necrosis factor-alpha, and vascular angiogenic growth factor were reduced (P < 0.001) with all treatments. They also increased (P < 0.05) the serum superoxide dismutase and glutathione levels and decreased serum nitrite and malondialdehyde levels. In addition, the number of Graafian follicles (P < 0.05), fertility, and pregnancy rates were increased with the treatments. G. pictum extracts showed anti-inflammatory, antioxidant, and fertilizing effects in Wistar rats with endometriosis. Lay summary: Asymptomatic in some individuals, endometriosis is an estrogen-dependent disease that causes infertility and severe pelvic pain, especially during menstrual periods and sexual intercourse. Higher cesarean rates worldwide have led to more cases of endometriosis (scar endometriosis). The delay of diagnosis (between 2 and 13 years) leads to increased misdiagnosis among patients and healthcare costs. There is no cure, but current treatments aim to alleviate spasms and pain by inhibiting estrogen production, and they are therefore unsuitable for women wishing to conceive, since they affect ovulation. Hence, there is a need to seek medical treatments that do not prevent pregnancy. Apart from its ornamental worth, Graptophyllum pictum, also called caricature plant, is traditionally used to relieve pain and treat reproductive disorders. After abdominal auto-transplantation of uterine fragments in rats, water-based and alcohol-based extracts of G. pictum promoted fertility by improving menstrual pain, egg development, and reducing cell damage and inflammation, which contribute to the progression of endometriosis.
Bruno Dupon Akamba Ambamba, Fils Armand Ella, Dany Joël Ngassa Ngoumen, Janvier Youovop, Guy Roussel Takuissu, Ruth Edwige Kemadjou Dibacto and 4 more
Metabolic Brain Disease
Nene Ahidjo, Paul F. Seke Etet, Leonard Ngarka, Frederic Maidawa Yaya, Ethel W Ndianteng, Aude L Eyenga Nna and 11 more
Brain Communications
Abstract Epidemiological evidence associates Toxoplasma gondii latent infection with the development of neuropsychiatric disorders, and various immunological and environmental factors play key pathophysiological roles through host immune response alterations. We investigated the cognitive and motor alterations occurring in the terminal stage of T. gondii infection in rats, and whether a low-protein diet, a high-fat diet or ovariectomy may accelerate their development, given the role of malnutrition and menopause on immunity and resistance to infection. In two sets of experiments, 2-month-old (157.5 ± 4.3 g, n = 42) male (n = 18) and female (n = 24) Wistar rats were infected with T. gondii (ATCC 40050). Open-field and elevated plus maze tests were performed in the terminal stage of infection first and then in the early stage in low-protein diet–fed, high-fat diet–fed and ovariectomized infected rats. Late-stage (90 days) infected and early-stage (17 days) low-protein diet–fed groups showed significant decreases in body weight (42.42%↓, P = 0.016 and 57.14%↓, P &lt; 0.001 versus non-infected, respectively), increases in body temperature (P = 0.001 and P &lt; 0.001, respectively), decreases in blood glucose levels (P = 0.006 and P = 0.020, respectively), signs of cognitive and motor impairment and lower neuron counts. The alterations observed in high-fat diet–fed and ovariectomized infected animals were milder. Low-protein diet feeding to T. gondii-infected rats accelerated the occurrence of the infection terminal stage. Thus, a diet low in proteins could transform a slow early-stage T. gondii infection into an active neurotoxoplasmosis with neuropsychiatric manifestations and possible neurodegeneration in rats.
Christelle Massop Wamba Ndé, Séfirin Djiogue, Franklin Zemo Gamo, Charline Florence Awounfack, Pauline Donn, Lucía Cassani and 4 more
Biologia
Youmbi Kammogne Ivana Gilberte Cyrielle, Godwe Célestin, Nana Hugues Djeunga, Ndjengue Mindang Elisabeth Louise, Edoun Ebouel Ferdinand Lanvin, Jean M. Feugang and 1 more
American Journal of Food Sciences and Nutrition
Purpose: The aim of this study was to investigate the influence of breed, production system, and feeding type on meat quality, evaluating organoleptic and physicochemical traits and antioxidant status across selected local cattle breeds. Materials and Methods: The study was carried out on sirloin and blood samples taken in slaughterhouses from the hot carcass of male cattle, divided according to breed, production system and type of feed. The nutritional, organoleptic characteristics and oxidative status was assessed. Findings: The results revealed that meat from Goudali breed raised in a sedentary system exhibited significantly lower tenderness (p<.) and higher lipid (p<.) and protein (p<.) contents. Additionally, the meat displayed notably lower pH (p=.), reduced cortisol (p<.), and lower catalase (p<.), TAC (p<.), and FRAP (p=.) activities. Consumers preferred the meat of the White Fulani breed due to its color (p<.). In transhumant system, the meat was richer in dry matter (p=.), lipids (p<.), and fibres (p=.), while the sedentary system resulted in more tender (p=.) and red-dark colored meat (p<.), which consumers favored. Meat from cows under commercial feed were preferred by consumers (p<.) compared to grass-fed cows, exhibiting significantly higher lipid (p<.) and protein (p<.) levels as well as intense color (p=.). However, meat from grass-fed cows had significantly higher fibre content (p<.), tenderness (p<.), better taste (p=.), juiciness (p=.), and higher catalase (p=.) and TAC (p<.) activities. Implications to Theory, Practice and Policy: These findings underscore the importance of considering breed, production system, and feeding type when conserving, selecting, or improving beef breeds for both meat quantity and quality.
Zemo Gamo Franklin, Séfirin Djiogue, Charline Florence Awounfack, Adjoffoin Chiara Nange, Dieudonné Njamen
Traditional Medicine and Modern Medicine
Neurological disorders constitute 6.3% of the global disease burden in the world. With a global death rate of 12%, these diseases are an important cause of mortality. The burden of neurological disorders is higher in developing countries than in developed countries. However, there is little literature on neurological diseases in sub-Saharan Africa, including Cameroon. Due to the inadequate access to modern medicine and physicians, the high cost, and the side effects of the modern drugs, patients renounced treatment. Traditional medicine is thus presented as an alternative. The World Health Organization reports that about 75–80% of the population of developing countries, mostly in Africa, consult traditional healers and use traditional medicine for their healthcare. In Cameroon, traditional medicines still remain a major source for preventing, diagnosing, and/or treating several household diseases, including neurological disorders. This review analyzes the prevalence of neurological disorders in Cameroon, the ethnobotanical knowledge of medicinal plants used to manage nervous system disorders or symptoms, and the importance of pharmacological studies. Some studies done in hospitals located in two towns of Cameroon (Yaoundé and Douala) show that the main neurological disorders are headache and epilepsy. To manage these neurological disorders, many plants are used by traditional doctors and the population. In recent years, some researchers from different university laboratories of Cameroon have tried to elucidate the beneficial effects of plant extracts on neurological disorders, and more is still to be done to prove the pharmacological effects of traditional medicine on nervous system diseases.
Florette Motoum Tedjo, Séfirin Djiogue, Charline Florence Awounfack, Kevine Silihe Kamga, Jean Garba Kof, Benderline Christine Nana and 2 more
SM Journal of Urology
Benign prostatic hyperplasia (BPH) is one of the common disorders amongst the geriatric male population, affecting their quality of life. Since conventional drugs used for the treatment are sometimes accompanied by serious side effects, the search for alternative treatments remains urgent.
Etienne Djeuzong, Antoine Kavaye Kandeda, Séfirin Djiogue, Lewale Stéphanie, Danide Nguedia, Florence Tsofack Ngueguim and 3 more
Evidence-based Complementary and Alternative Medicine
Background. Alzheimer's disease is a neurological condition that affects about 44 million people worldwide. The available treatments target symptoms rather than the underlying causes. Ziziphus jujuba (Rhamnaceae) is widely used in traditional Cameroonian medicine to treat diabetes, pain, infections, and dementia. Previous studies reported that Z. jujuba aqueous macerate improves working memory impairment, but no study on the antiamnesic effect of a concoction of Z. jujuba in rats has been performed. Therefore, this study aimed to assess the antiamnesic and neuroprotective effects of an aqueous extract of Z. jujuba on scopolamine-induced cognitive impairments in rats. Methods. Learning and memory impairments were induced in rats by administering scopolamine (1 mg/kg, i.p.) to 58 rats for 15 days. Rats that developed learning and memory impairments in Morris water maze and Y-maze paradigms were divided into 7 groups (8 rats each) and treated daily for 15 days as follows: the normal control group received distilled water (10 ml/kg, p.o.), the negative control group received distilled water (10 ml/kg, p.o.), positive control groups either received donepezil (1.2 mg/kg, p.o.) or tacrine (10 mg/kg, p.o.), and the three test groups were given the extract (29, 57, and 114 mg/kg, p.o.). At the end of treatments, learning and memory impairments were determined using the same paradigms. Animals were then euthanized, and biochemical parameters of oxidative stress, inflammation, and apoptosis were analyzed in the hippocampus and prefrontal cortex. Results. On the 4th day of the acquisition phase in the Morris water maze, Z. jujuba (29 and 114 mg/kg) reduced ( <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" id="M1"> <a:mi>p</a:mi> <a:mo><</a:mo> <a:mn>0.001</a:mn> </a:math> ) the latency to reach the platform, while in the retention phase, Z. jujuba (57 and 114 mg/kg) decreased ( <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" id="M2"> <c:mi>p</c:mi> <c:mo><</c:mo> <c:mn>0.001</c:mn> </c:math> ) the time to reach the platform and increased the time in the target quadrant ( <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" id="M3"> <e:mi>p</e:mi> <e:mo><</e:mo> <e:mn>0.05</e:mn> </e:math> ) compared to control. Surprisingly, the extract failed to affect spontaneous alternations in the Y-maze. Furthermore, the extract (29, 57, and 114 mg/kg) reversed ( <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" id="M4"> <g:mi>p</g:mi> <g:mo><</g:mo> <g:mn>0.001</g:mn> </g:math> ) scopolamine-induced oxidative stress, inflammation, and apoptosis. This was supported by the reduction of neuronal alterations in the hippocampus and prefrontal cortex. Conclusions. Compared to donepezil, a standard drug against Alzheimer’s disease, these findings suggest that Z. jujuba extract possesses antiamnesic and neuroprotective effects, and these effects are mediated in part through antioxidant, anti-inflammatory, and antiapoptotic activities. These findings help to explain its use in treating psychiatric disorders in Cameroon’s folk medicine.
Zemo Gamo Franklin, Séfirin Djiogue, Seke Etet Paul Faustin, Pieme Constant Anatole, Babiker Ali Yousif, Awounfack Charline Florence and 2 more
Journal of Experimental Pathology
The cortex, hippocampus, and amygdala are among the brain regions where estrogens may act to improve cognition, memory and mood. In these regions, estrogens have many beneficial effects, including neuroprotection, neurogenesis, as well as neurotrophic, antioxidant, and anti-inflammatory effects
Zemo Gamo Franklin, Ateba Sylvin Benjamin, Ketcha Wanda Germain Jean Magloire, Séfirin Djiogue, Dieudonné Njamen
International Journal of Engineering Applied Sciences and Technology
Pachystela brevipes (Bak.) Engl (Sapotaceae) is a plant used in West region of Cameroon to improve conception and alleviate vaginal dryness in elderly women. Thus, this study was designed to evaluate the potential estrogenic of the decoction of stem bark of P. brevipes (175, 350 and 700 mg/kg BW) using a 3-day uterotrophic assay in ovariectomized rats. P. brevipes extract had no effect uterine wet weight while, significantly (p < 0.05) increased uterine (at 350 and 700 mg/kg) and vaginal (at 700 mg/kg) epithelial thickness. Moreover, this extract induced an E2V-like effect on mammary gland by increased the diameter of alveoli and induced eosinophil secretion at all tested doses. These results suggest that P. brevipes extract is endowed with estrogenic properties and could justify its traditional used.
A. K. Srivastava, Séfirin Djiogue
South African Journal of Botany
Biomedical Journal of Scientific & Technical Research
Djiogue Sefirin*1, Adjoffoin Chiara Nange1, Motoum Tedjo Florette1, Zemo Gamo Franklin1,2, Awounfack Charline Florence1, Kamtchouing Pierre1 and Njamen Dieudonné1 Author Affiliations 1Laboratory of Animal Physiology, Department of Animal Biology and Physiology, Faculty of Science, Cameroon 2Department of Psychology, Faculty of Arts, Letters and Social Sciences, Cameroon Received: July 09, 2019 | Published: July 19, 2019 Corresponding author: Sefirin Djiogue, Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde I, P.O. Box 8069, Yaounde-Cameroon DOI: 10.26717/BJSTR.2019.19.003356 Also View In:
Siméon Pierre Choukem, Derrick Tembi Efie, Séfirin Djiogue, François Folefack Kaze, Yannick Mboue-Djieka, Thadée Boudjeko and 3 more
PLoS ONE
BACKGROUND: Hydroquinone-containing creams cause false increases in capillary glycemia. However, the magnitude of this false increase, and the means to reverse it have not been investigated. OBJECTIVE: To evaluate the technical and clinical impact of hydroquinone-containing creams on capillary glycemia and investigate the efficacy of hand washing and other common practices, in reversing cream effects. METHODS: We included 91 participants in a quasi-experimental study in Buea, Cameroon. After determining the hydroquinone content of a cream, Caro Light, we used two glucometers with different enzymatic systems (Accu-Chek Active and OneTouch Ultra 2) to measure fasting glycemia after: initial hand washing (reference), application of 1 ml of hydroquinone-containing cream, finger swabbing with wet gauze, sanitizer application and a series of three hand washings following cream application. Reference glycemia was compared to those obtained after various interventions. Statistical significance was assessed by paired sample t-test, clinical significance by total error allowable (TEa), and clinical impact by Parke's error grid analysis. RESULTS: The mean differences in capillary glycemia (Intervention-reference) measured by Accu-Chek Active in mg/dl were 28, 27, 38, 16, 4, and -2 after cream application, finger swabbing, sanitizer application, one, two, and three hand washings respectively. Corresponding values for OneTouch Ultra2 were 41, 44, 64, 22, 5 and -5. These differences, except after two and three hand washings were both statistically (p < 0.0001) and clinically significant (TEa). After cream application, Accu-Check had 9.9% of values in Parke's Zones C-E, while OneTouch had 18.7%. CONCLUSION: Hydroquinone-containing creams cause significant false increase in capillary glycemia irrespective of the enzymatic system of the glucometer used, and can lead to potentially wrong clinical decisions. A minimum of two hand washings is required prior to capillary glucose measurement.
Séfirin Djiogue, Armando Blondel Djiyou Djeuda, Paul F. Seke Etet, Germain Jean Magloire Ketcha Wanda, Rudig Nikanor Djikem Tadah, Dieudonné Njamen
Behavioral and Brain Functions
BACKGROUND: Estrogen deficiency is linked to changes in several physiological processes, but the extent to which it associates with cognitive changes in menopause context is controversial. RATIONALE: We evaluated the impact of ovariectomy on memory processes and normal exploratory behavior in Wistar rats. METHODS: Young adult rats (4-6 months) were either ovariectomized (OVX group) (N = 10), sham operated (N = 10), or untouched (naïve controls) (N = 8). Afterwards, they were monitored for 12 weeks during which their cognitive functions were evaluated at first week (S1), second (S2), every 3 weeks (S5, S8) and then at week 12 (S12) using: (i) object recognition test to evaluate the short-term and long-term non-spatial memory; (ii) the object placement test to assess the spatial memory; and (iii) normal exploratory behavior components like locomotor and vertical activities in an open field arena. RESULTS: Marked changes in ovariectomized rats were observed in long-term non-spatial memory (~ 40% change vs. naïve and sham, P < 0.001) and spatial memory (~ 30% change, P < 0.05) from S2. Instead, from S5 the exploratory behavior was affected, with decreases in line crossing and rearing episode numbers (~ 40% change, P < 0.01), and in the time spent in the center of open field arena (~ 60% change, P < 0.01). CONCLUSIONS: Our findings support the involvement of sex hormones in cognitive functions in female rats and suggest that controversy on the importance of cognitive affections in menopause context may emerge from differences between short-term and long-term memory processes.
Charline Florence Awounfack, Marie Alfrede Mvondo, Stéphane Zingue, Sylvin Benjamin Ateba, Séfirin Djiogue, Rosette Megnekou and 2 more
Medicines
Background: Despite the wide use of leaves of Myrianthus arboreus (Cecropiaceae) in several African countries including Cameroon as food and against amenorrhea and female infertility, it has never been tested for this purpose. Methods: Using immature female Wistar rats, the impact of M. arboreus on the sexual maturation parameters (vaginal opening, ovarian relative weight and follicle maturation, gonadotropins and ovarian hormones serum levels) and fertility index has been evaluated through a 30-day oral administration of aqueous and methanol extracts of leaves at the doses of 20, 110 and 200 g/kg/day. Results: Aqueous extract increased the ovarian relative weight (p < 0.001), progesterone (p < 0.001) and gonadotropins (p < 0.001) serum levels, and induced the maturation of ovarian follicles. The methanol extract additionally induced an early vaginal opening (p < 0.001), uterine growth (p < 0.01) and increased estradiol (p < 0.001) serum levels. The fertility index generally increased following treatments, while the gestation rate remained almost unaffected except at the highest tested dose of M. arboreus extracts where lowest values were observed. Conclusion: Globally, M. arboreus induced an early puberty onset and an increased fertility rate validating at least in part its traditional use for female infertility.
Zemo Gamo Franklin, Séfirin Djiogue, Ketcha Wanda Germain Jean Magloire, Seke Etet Paul Faustin, Yonkeu Tatchou Floriane Gaëlle, Djikem Tadah Rudig Nikanor and 2 more
Journal of Pharmacy and Pharmacology
On study of the effects of estrogen deficiency on anxiety disorder by using ovariectomised animals, one discrepancy was the difference in behavioral testing delay following ovariectomy and the paradigms used. Thus, the aim of this study was to evaluate the anxiogenic effects of fourteen-day estrogen decline subsequent to ovariectomy on Wistar rats using EPM (elevated plus-maze) and open field tests. As results, fourteen days of estrogens decline has induced an increase of anxiety-related behaviour by a reduction of the percentage of the number of entries into the open arm (p < 0.01) and an increase of the percentage of the number of entries into the closed arm (p < 0.01) during the elevated plus-maze test. This anxiety-like behaviour was confirmed on the open field test by a reduction of time spent in the centre of the arena (p < 0.05) as well as a reduction of crossing (p < 0.05) and an increase of the weight of faecal boli (p < 0.05) and grooming (p < 0.01). Meanwhile, the administration of diazepam or estradiol valerate (1 mg/kg BW each) has corrected the anxious-like behaviour in both tests paradigms. These results suggest that fourteen days of estrogens decline was associated with an anxiety-related behaviour. This experimental model can constitute an excellent tool for the study of anxiolytic substances in menopause-related anxiety.
Germain Jean Magloire Ketcha Wanda, Séfirin Djiogue, Sosthène Onésiphore Djoussi Njimfo, Charline Florence Awounfack, Dieudonné Njamen
International Journal of Phytomedicine
<p><em>Tragia benthamii</em> Baker (Euphorbiaceae) and <em>Graptophyllum pictum</em> Linn (Acanthaceae) are two Cameroonian medicinal plants traditionally used against female reproductive tract disorders, during and after the reproductive period, and as an abortifacient. Since there were no scientific data supporting the above claims and pharmacological studies characterizing their estrogenic properties, we therefore aimed to evaluate their ability to induce estrogen-like effects on primary estrogens targets, uterine, vagina and mammary gland; as well as their ability to alleviate hot flushes in ovariectomized adult rats. For this purpose, we applied a 3-day uterotrophic assay to determine the estrogenic effects of each extract and the mixture of both plants as used by traditional practitioners. The extracts were administered orally for 3 days to the 10 to 12 weeks aged ovariectomized rats. The results obtained showed that the aqueous extract of<em> T. benthamii </em>at the dose of 500 mg / kg BW, the aqueous extract of <em>G. pictum</em> at all the tested doses as well as the aqueous extract of the mixture at 275 mg / kg body weight induced a significant increase (p ˂ 0.01) of the uterine epithelium thickness. In addition, the aqueous extract of <em>T. benthamii</em> at the dose of 500 mg / kg BW, as well as the aqueous extract of the mixture at the doses of 50 and 275 mg / kg induced acinar development and eosinophil secretions. These results are proof of estrogen-like effects of <em>T. benthamii</em> and <em>G. pictum</em> and therefore justify the traditional use of these plants. This suggests the presence in these plants, of secondary metabolites with estrogenic properties, can induce cell proliferation, and to correct disorders of post-oophorectomy œstrogénopénia in the Wistar rats and therefore menopausal disorders.</p>
Annekathrin M. Keiler, Séfirin Djiogue, Tino Ehrhardt, Oliver Zierau, Léandros Skaltsounis, Maria Halabalaki and 1 more
Planta Medica
Oleocanthal is a bioactive compound from olive oil. It has attracted considerable attention as it is anti-inflammatory, antiproliferative, and has been shown to possess neuroprotective properties in vitro and in vivo. Delineated from its polyphenolic structure, the aim of this study was to characterize oleocanthal towards estrogenic properties. This might contribute to partly explain the beneficial effects described for the Mediterranean diet. Estrogenic properties of oleocanthal were assessed by different methods: a) stimulation of reporter gene activity in MVLN or RNDA cells either expressing estrogen receptor α or β, b) stimulation of luciferase reporter gene activity in U2OS osteosarcoma cells expressing estrogen receptor α or β, and c) elucidation of the impact on estradiol-induced gene expression in U2OS cells transduced with both estrogen receptors. Depending on the cell line origin, oleocanthal inhibited luciferase activity (MVLN, U2OS-estrogen receptor β) or weakly induced reporter gene activity at 10 µM in U2OS-estrogen receptor α cells. However, oleocanthal inhibited stimulation of luciferase activity by estradiol from both estrogen receptors. Oleocanthal, if given alone, did not stimulate gene expression in U2OS cells, but it significantly modulated the response of estradiol. Oleocanthal enhanced the effect of estradiol on the regulation of those genes, which are believed to be regulated through heterodimeric estrogen receptors. As the estrogenic response pattern of oleocanthal is rather unique, we compared the results obtained with oleacein. Oleocanthal binds to both estrogen receptors inducing estradiol-agonistic or antiagonistic effects depending on the cell line. Regarding regulation of gene expression in U2OS-estrogen receptor α/β cells, oleocanthal and oleacein enhanced estradiol-mediated regulation of heterodimer-regulated genes.
Dieudonné Njamen, Marie Alfrede Mvondo, Séfirin Djiogue, Germain Jean Magloire Ketcha Wanda, Chantal Magne Nde, Günter Vollmer
Planta Medica
Approximately 80 % of the population in Africa use traditional medicinal plants to improve their state of health. The reason of such a wide use of medicinal plants has been mainly attributed to their accessibility and affordability. Expectation of little if any side effects, of a "natural" and therefore safe treatment regimen, as well as traditional beliefs additionally contribute to their popularity. Several of these plants are used by women to relieve problems related to their reproductive health, during or after their reproductive life, during pregnancy, or following parturition. The African pharmacopoeia thus provides plants used for preventing and/or treating gynecological infections, dysmenorrhea, irregular menstruations, oligomenorrhea or protracted menstruation, and infertility. Such plants may then be used as antimicrobians, emmenagogues, or as suppressors of uterine flow. African medicinal plants are also used during pregnancy for prenatal care, against fetal malposition or malpresentation, retained dead fetus, and against threatened abortion. Some others are used as anti-fertilizing drugs for birth control. Such plants may exert various activities, namely, anti-implantation or early abortifacient, anti-zygotic, blastocytotoxic, and anti-ovulatory effects. Some herbs could also act as sexual drive suppressors or as a post-coital contraceptive by reducing the fertility index. A number of these plants have already been subject to scientific investigations and many of their properties have been assessed as estrogenic, oxytocic, or anti-implantation. Taking into account the diversity of the African pharmacopoeia, we are still at an early stage in the phytochemical and pharmacological characterization of these medicinal plants that affect the female reproductive system, in order to determine, through in vitro and in vivo studies, their pharmacological properties and their active principles.
Maria Halabalaki, Séfirin Djiogue, Job Tchoumtchoua, NE Arapogianni, A Paschali, Xanthippi Alexi and 4 more
Planta Medica
Plants originated mainly from Mediterranean region as well as from other higly deverse hot-spots all over the world have been phytochemically explored in the context of our continuing study towards the discovery of novel, active natural products presenting high affinity to nuclear reseptors. In particular estrogen receptor (ER) and peroxisome proliferator-activated receptor (PPAR) were the target-reseptors under investigation. Our study is mainly focused to the identification of secondary metabolites which present the capability to activate both isoforms of estrogen receptor (ERα& ERβ) [1] as well as the two isoforms of the peroxisome proliferator-activated receptor (PPARγ& PPARδ) [2]. Numerous of secondary metabolites belonging mostly to simple phenolics, to flavonoids and specifically to flavones, flavonols and methylether derivatives thereof and isoflavonoids mainly isoflavones, prenylated isoflavones and 2-arylbenzofurans have been identified using a bioguided approach or LC-MS-based methodologies. The structure elucidation of the isolated compounds was performed via HRMSn and 1 & 2D NMR [3], [4], [5], [6]. The biological evaluation was focused on the determination of the relative binding activity (RBA values) of the purified compounds to ERα and ERβ and/or PPARγ and PPARδ as well as on the exploration of the biological michanism of action using e-screen, reporter gene and analysis of gene expression assays. Determination of their proliferative and/or cytotoxic properties was also performed. A series of novel natural compounds belonging mostly to 2-arylbenzofurans and prenylated isoflavones were identified whereas a numerous thereof found to present significant estrogenic, antiestrogenic, SERM and/or antidiabetic activity [7], [8], [9]. References: 1. Miksicek, RJ, (1993) Mol. Pharmac. 44: 37–43. 2. Knouff, C. and Auwerx, J. (2004) Endoc. Rev. 25: 899–918. 3. Halabalaki, M et al., (2000)J. Nat. Prod. 63 (8): 1672–1674. 4. Halabalaki, M et al., (2006) Planta Medica 72, (6) 488–493. 5. Halabalaki, M et al., (2008)J. Nat. Prod. 71 (11): 1934–1937. 6.Djiogue, S. et al. (2009)J. Nat. Prod. 72 (9): 1603–1607. 7. Katsanou, SE (2007)J. Ster. Biochem. Mol. Biol. 104 (3–5): 228–36. 8. Dontas I, (2006) Maturitas 53 (2): 234–242. 9. Arapogiani N-E (2007), 45th Int. Meeting & Ann. Meeting of GA, Graz, Austria.
Séfirin Djiogue, Maria Halabalaki, D Njamen, Μichael N. Alexis, Z. Tanee Fomum, AL Skaltsounis
Planta Medica
In most developing countries, the traditional medicine based on preparations from medicinal plants still stays one of the main appeals. Many Erythrina species for example are used in the traditional system of medicine in Cameroon for the treatment of menopause related illnesses. Additionally, the Leguminosae family is well known for its great content in isoflavonoids which have been shown to exhibit numerous biological activities including estrogenic/anti-estrogenic activity (so called phytoestrogens) [1]. In our endeavour, aiming to discover novel active natural products based on the long-established empirical traditional knowledge, phytochemical investigation of Erythrina poeppigiana (Fabaceae), a Leguminosae species growing in humid and sub-humid tropical lowland is undertake. After a qualitative evaluation of DCM and MeOH extracts using TLC and HPLC-PDA, further investigation was performed on both extracts leading to isolation and structure determination of a number of secondary metabolites using several chromatographic (VCC, CC, FCPC, HPLC) and spectroscopic (UV, MS, 1&2D NMR) techniques, respectively. At this stage of the work, 10 isoflavonoids (5 novel compounds), one pterocarpan and 3 simple phenolic ester were isolated from the DCM extract and 4 Erythrina alkaloids from the MeOH extract. The ability of the isolated compounds derived from the DCM extract to bind to the estrogen receptor (ER α & ER β ) was estimated. Most of them found to be potent ligands. References: [1] Veitch, N.C. (2007) Nat. Prod. Rep. 24:417–464.
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