Dieudonné NJamen

Prof. Dieudonné NJamen


Research Focus & Metrics

Academic Career Length

24Years (2003-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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16 July 2018 in Behavioral and Brain Functions
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SDSefirin Nange DJIOGUE
Sefirin Nange DJIOGUE
ADArmando Blondel Djiyou Djeuda
Armando Blondel Djiyou Djeuda
PEPaul Faustin Seke Etet
Paul Faustin Seke Etet
GWGermain Jean Magloire Ketcha Wanda
Germain Jean Magloire Ketcha Wanda
RTRudig Nikanor Djikem Tadah
Rudig Nikanor Djikem Tadah
DNDieudonné NJamen
Dieudonné NJamen
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. We evaluated the impact of ovariectomy on memory processes and normal exploratory behavior in Wistar rats. 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. 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). 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.

20 December 2011 in Phytotherapy Research
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MMM.A. Mvondo
M.A. Mvondo
DNDieudonné NJamen
Dieudonné NJamen
SFS. Tanee Fomum
S. Tanee Fomum
JWJ. Wandji
J. Wandji

1 January 2020 in Journal of Ethnopharmacology
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SZStephane Zingue
Stephane Zingue
AYAbel Joël Gbaweng Yaya
Abel Joël Gbaweng Yaya
TMThomas Michel
Thomas Michel
DNDerek Tantoh Ndinteh
Derek Tantoh Ndinteh
JRJochen Rutz
Jochen Rutz
RBRoman A. Blaheta
Roman A. Blaheta

28 March 2013 in Planta Medica
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DNDieudonné NJamen
Dieudonné NJamen
MMMarie Alfrede Mvondo
Marie Alfrede Mvondo
SDSefirin Nange DJIOGUE
Sefirin Nange DJIOGUE
GWGermain Jean Magloire Ketcha Wanda
Germain Jean Magloire Ketcha Wanda
CNChantal Beatrice Magne Nde
Chantal Beatrice Magne Nde
GVGünter Vollmer
Günter Vollmer
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.

21 January 2017 in BMC Complementary and Alternative Medicine
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SZStephane Zingue
Stephane Zingue
CNChantal Beatrice Magne Nde
Chantal Beatrice Magne Nde
TMThomas Michel
Thomas Michel
DNDerek Tantoh Ndinteh
Derek Tantoh Ndinteh
JTJules Tchatchou
Jules Tchatchou
DNDieudonné NJamen
Dieudonné NJamen
Since the biological properties of propolis depend to the plants that can be found in a specific region, propolis from unexplored regions attracts the attention of scientists. Ethanolic extract of Cameroonian propolis (EEP) is used to treat various ailments including gynecological problems and amenorrhea. Since there were no scientific data to support the above claims, the present study was therefore undertaken to assess estrogenic properties of Cameroonian propolis. To achieve our goal, the ability of EEP to induce MCF-7 cells proliferation in E-screen assay as well as to activate estrogen receptors α (ERα) and β (ERβ) in cell-based reporter gene assays using human embryonic kidney cells (HEK293T) transfected with ERs was tested. Further, a 3-day uterotrophic assay was performed and the ability of EEP to alleviate hot flushes in ovariectomized adult rats was evaluated. In vitro, EEP showed an antiestrogenic activity in both HEK293T ER-α and ER-β cells. In vivo, EEP induced a significant increase in a bell shape dose response manner of the uterine wet weight, the total protein levels in the uterus, the uterine and vaginal epithelium height and acini border cells of mammary gland with the presence of abundant eosinophil secretions. Moreover, EEP induced a significant decrease in the total number, average duration as well as frequency of hot flushes after 3 days of treatment in rat (equivalent to a month in woman). The dose of 150 mg/kg exhibited the most potent estrogenic effects among all the tested doses. The UPLC-HRMS analysis showed the presence of caffeic acid derivatives and trirtepernoids in EEP, which are well known endowed with estrogenic properties. These results suggest that Ethanolic extract of Cameroonian propolis has estrogen-like effects in vivo and may alleviate some menopausal problems such as vaginal dryness and hot flushes. Ethanol-extracted Cameroobian propolis exhibited in vitro and in vivo estrogen-like effects. This extract may contain promising phytoestrogens.

25 March 2018 in BioMed Research International
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SZStephane Zingue
Stephane Zingue
ANAmstrong Nang Njuh
Amstrong Nang Njuh
ATAlain Brice Tueche
Alain Brice Tueche
JTJeremie Tamsa
Jeremie Tamsa
ETEdwige Nana Tchoupang
Edwige Nana Tchoupang
DNDieudonné NJamen
Dieudonné NJamen
The present study was designed to evaluate thein vitroandin vivoantitumor effects ofA. seyalhydroethanolic extract on breast cancer. The cytotoxicity ofA. seyalextract was evaluated using resazurin reduction assay in 9 cell lines. Further, the protective effect of the hydroethanolic extract ofA. seyalstem barks was evaluated on 7,12-dimethylbenz(a)anthracene- (DMBA-) induced breast cancer rat model. Incidence, burden, volume, and histological analysis of mammary tumors were measured. TheAcacia seyalextract exhibited CC50of 100 in MCF-7 cells after 24 h.In vivo, no tumors were detected in rats from the control group, while 11 rats out of 12 (91.66%) developed mammary tumors in the DMBA-exposed group receiving only the vehicle.Acacia seyalextract significantly (p<0.01) and in the dose-dependent manner reduced tumor incidence (3 rats out of 12 at the dose of 300 mg/kg), burden [62.1% (150 mg/kg) and 65.8% (300 mg/kg)], and mass. It protected rats against DMBA-induced breast hyperplasia, with an optimal effect at the dose of 300 mg/kg. Taken altogether, these results suggest that the hydroethanolic extract ofAcacia seyalmight contain phytoconstituents endowed with antitumoral properties, which could protect against the breast cancer induced in rats.