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Wabo H.K.,University of Dschang | Kowa T.K.,University of Dschang | Lonfouo A.H.N.,University of Dschang | Tchinda A.T.,Institute of Medical Research and Medicinal Plants Studies IMPM | And 4 more authors.
Records of Natural Products | Year: 2012

A benzophenone, 2,2',5,6'-tetrahydroxybenzophenone (1), and one xanthone, 5-hydroxy-3- methoxyxanthone (2), were newly described as natural products from the leaves and the stem barks of Hypericum lanceolatum, along with the known compounds friedelin (3), betulinic acid (4), allanxanthone A (5), 1,3,6-trihydroxyxanthone (6), isogarcinol (7), sitosterol 3-O-β-D-glucopyranoside (8), 1-hydroxy-6- methoxyxanthone (9), 6,7-dihydroxy-1,3-dimethoxyxanthone (10), 3-hydroxy-5-methoxyxanthone (11), 1,7- dihydroxy-3,6-dimethoxyxanthone (12) and calophyllumin A (13). Their structures were elucidated by spectroscopic means and comparison with published data. © 2011 Reproduction is free for scientific studies. Source

Ndontsa B.L.,University of Dschang | Tchinda A.,Institute of Medical Research and Medicinal Plants Studies IMPM | Teponno R.B.,University of Dschang | Mpetga J.S.,University of Dschang | And 2 more authors.
Natural Product Communications | Year: 2012

Column chromatography of the n-butanol extract of the stem of Ardisia kivuensis (Myrsinaceae) led to the isolation of a new triterpenoid saponin, ardisikivuoside (1) {3-O-β-D-xylopyranosyl-(1→3)-β-D- glucopyranosyl-(1rarr;4)-β-D-xylopyranosyl-3β-hydroxy-13β, 28-epoxyoleanan-16-oxo-30-al}. The structure was elucidated on the basis of spectral studies. Source

Tchinda A.T.,Institute of Medical Research and Medicinal Plants Studies IMPM | Jansen O.,University of Liege | Nyemb J.-N.,University of Yaounde I | Tits M.,University of Liege | And 3 more authors.
Journal of Natural Products | Year: 2014

A reinvestigation of the roots of Strychnos icaja resulted in the isolation of a new bisindole alkaloid named strychnobaillonine (1) with original C-17-N-1 and C-23-C-17 junctions, in addition to sungucine, bisnordihydrotoxiferine, and strychnohexamine (2). Compound 1 showed potent activity against the chloroquine-sensitive 3D7 strain of Plasmodium falciparum in vitro with an IC50 value of 1.1 μM. The structures of the compounds were defined by detailed spectroscopic analyses, especially 1H and 13C NMR, DEPT, HSQC, COSY, NOESY, HMBC, and HRESIMS. The proposed absolute configuration was based on biosynthetic considerations and spectroscopic data (CD, NMR) supported by molecular modeling. © 2014 The American Chemical Society and American Society of Pharmacognosy. Source

Mkounga P.,University of Yaounde I | Tiabou A.T.,Institute of Medical Research and Medicinal Plants Studies IMPM | Kouam J.,University of Yaounde I
Chemical and Pharmaceutical Bulletin | Year: 2010

Three new olean-12-ene derivatives (1-3), together with known urs-12-ene-3β, 28-diol (4) were isolated from the stem root of Cylicodiscus gabunensis. The structures of the new compounds were established by chemical and spectroscopic means as β-amyrin-n-nonyl ether (1), 22α- hydroxyolean-12-en-3β-yl-β-D-galactopyranoside (2), and 24-hydroxyolean-12-en-3β-yl-β-D-glucopyranoside (3). © 2010 Pharmaceutical Society of Japan. Source

Boyom F.F.,University of Yaounde I | Fokou P.V.T.,University of Yaounde I | Tchokouaha L.R.Y.,University of Yaounde I | Tchokouaha L.R.Y.,Institute of Medical Research and Medicinal Plants Studies IMPM | And 7 more authors.
Antimicrobial Agents and Chemotherapy | Year: 2014

Toxoplasmosis and amebiasis are important public health concerns worldwide. The drugs currently available to control these diseases have proven limitations. Therefore, innovative approaches should be adopted to identify and develop new leads from novel scaffolds exhibiting novel modes of action. In this paper, we describe results from the screening of compounds in the Medicines for Malaria Venture (MMV) open access Malaria Box in a search for new anti-Toxoplasma and anti-Entamoeba agents. Standard in vitro phenotypic screening procedures were adopted to assess their biological activities. Seven anti-Toxoplasma compounds with a 50% inhibitory concentration (IC50) of <5μM and selectivity indexes (SI) of >6 were identified. The most interesting compound was MMV007791, a piperazine acetamide, which has an IC50of 0.19μM and a selectivity index of >157. Also, we identified two compounds, MMV666600 and MMV006861, with modest activities against Entamoeba histolytica, with IC50s of 10.66μM and 15.58μM, respectively. The anti-Toxoplasma compounds identified in this study belong to scaffold types different from those of currently used drugs, underscoring their novelty and potential as starting points for the development of new antitoxoplasmosis drugs with novel modes of action. Copyright © 2014, American Society for Microbiology. All Rights Reserved. Source

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