Institute of Medical Research and Medicinal Plants Studies IMPM

Yaoundé, Cameroon

Institute of Medical Research and Medicinal Plants Studies IMPM

Yaoundé, Cameroon
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PubMed | Jackson State University, Institute of Medical Research and Medicinal Plants Studies IMPM and High Institute of Environmental science
Type: Journal Article | Journal: Journal of molecular pharmaceutics & organic process research | Year: 2015

A majority of Africans rely on traditional medicine as the primary form of health care. Yet most traditional medicine products have a short shelf life, especially for water-based formulations such as macerations, infusions and decoctions. Indeed, many of these water extracts become unfit for human consumption after five to seven days of conservation either because of the degradation or toxicity of active components, and/or the growth of pathogenic organisms. The purpose of this study was to describe and apply a new approach for the development of an improved traditional medicine (ITM) that is cheap, very efficient, not toxic, and easy to produce, and that can be conserved for a longer time without a significant loss of activity. Hence,

PubMed | Centers for Disease Control and Prevention, University of Yaounde I, Tulane National Primate Research Center, University of Cincinnati and 3 more.
Type: Journal Article | Journal: The Journal of eukaryotic microbiology | Year: 2016

Several enteric microsporidia species have been detected in humans and other vertebrates and their identifications at the genotype level are currently being elucidated. As advanced methods, reagents, and disposal kits for detecting and identifying pathogens become commercially available, it is important to test them in settings other than in laboratories with state-of-the-art equipment and well-trained staff members. In the present study, we sought to detect microsporidia DNA preserved and extracted from FTA (fast technology analysis) cards spotted with human fecal suspensions obtained from Cameroonian volunteers living in the capital city of Yaound to preclude the need for employing spore-concentrating protocols. Further, we tested whether amplicon nucleotide sequencing approaches could be used on small aliquots taken from the cards to elucidate the diversity of microsporidia species and strains infecting native residents. Of 196 samples analyzed, 12 (6.1%) were positive for microsporidia DNA; Enterocytozoon bieneusi (Type IV and KIN-1), Encephalitozoon cuniculi, and Encephalitozoon intestinalis were identified. These data demonstrate the utility of the FTA cards in identifying genotypes of microsporidia DNA in human fecal samples that may be applied to field testing for prevalence studies.

PubMed | University of Dschang, Carleton University, Institute of Medical Research and Medicinal Plants Studies IMPM and Leibniz Institute of Plant Biochemistry
Type: | Journal: Fitoterapia | Year: 2016

A new dihydroflavonol-flavonol biflavonoid derivative, named ericoside was isolated from the ethanol extract of the whole plant of Erica mannii along with the known flavonoid, taxifolin 3-O--L-rhamnopyranoside; and two readily available sterols (sitosterol, sitosterol 3-O--D-glucopyranoside). The isolation was performed using chromatographic methods and the structure of purified molecules were elucidated using spectroscopic techniques (e.g. MS, NMR) and by comparison with literature data. The crude ethanol extract, ericoside, and taxifolin 3-O--L-rhamnopyranoside were tested against ten Gram-negative bacteria including multidrug resistant clinical isolates using a broth microdilution method. The crude ethanol extract showed no noteworthy activity. Of the purified compounds, ericoside displayed moderate activity against the resistant Escherichia coli AG100 with a MIC of 64 g/mL.

PubMed | University of Yaounde I, Noguchi Institute, Institute of Medical Research and Medicinal Plants Studies IMPM and University of Ghana
Type: | Journal: International journal of mycobacteriology | Year: 2017

Buruli ulcer (BU) is a neglected tropical disease caused by a mycobacteria, Mycobacterium ulcerans. The WHO recommended Rifampicin-Streptomycin combination side effects and poor compliance, leaves rural populations with no choice than to patronise indigenous remedies. This study is aimed at validating medicinal plants used in traditional medicine to treat BU by investigating the in vitro efficacy and safety as well as their composition in active molecules.A short report-based survey was used to identify medicinal plants used traditionally for BU treatment. Maceration of collected plant samples in methanol, hydroethanolic, ethanol, dichloromethane, and hexane, resulted in a total of 67 extracts assessed for antimycobacteria activity against Mycobacterium smegmatis and Mycobacterium ulcerans using the Resazurin Microtiter Assay. The cytotoxicity effect of promising extracts was assessed on normal human liver cells using the MTT assay. The bio-guided fractionation of the promising extracts led to the isolation of active compounds.Majority of plants prepared as infusion, decoction, poultice, and macerate were administered topically. Significant antimycobacterial activity with MIC values ranging from 16 to 250g/mL was recorded against M. smegmatis (25 extracts) and M. ulcerans (17 extracts).The results completed support the use these plants in the indigenous knowledge against BU. Further analyses of active principles might lead to new drug toe fight against BU.

Tchinda A.T.,Institute of Medical Research and Medicinal Plants Studies IMPM | Ngono A.R.N.,University of Douala | Tamze V.,Institute of Medical Research and Medicinal Plants Studies IMPM | Jonville M.-C.,University of Liège | And 3 more authors.
Planta Medica | Year: 2012

From the stem bark of Strychnos malacoclados, one new bisindole alkaloid, 3-hydroxylongicaudatine Y (1), was isolated along with the known alkaloids vomicine (2), bisnordihydrotoxiferine (3), divarine (4), longicaudatine (5), longicaudatine Y (6), and longicaudatine F (7). All the compounds were tested for their antimalarial activity against the chloroquine-sensitive 3D7 and -resistant W2 strains of Plasmodium falciparum. Longicaudatine was the most active compound with IC 50 values of 0.682 and 0.573 μM, respectively. The activity of compounds 1, 3, 4, 6, and 7 against the two strains ranged from 1.191 to 6.220 μM and 0.573 to 21.848 μM, respectively. Vomicine (2), the only monomer isolated, was inactive. The alkaloids of the longicaudatine-type (1, 5-7) were more active than those of the caracurine-type (3-4). The presence of the ether bridge in the molecule seems to increase the antiplasmodial activity. Compounds 1, 5, and 7 were tested against the WI-38 human fibroblast cell line. Longicaudatine was the most cytotoxic compound with an IC 50 of 2.721 μM. Longicaudatine F was 40-46 times more active against the two strains of P. falciparum than against the human fibroblasts and was thus considered as the more selective alkaloid. The structures of the compounds were determined based on the analysis of their spectral data. © Georg Thieme Verlag KG Stuttgart.

Tchinda A.T.,Institute of Medical Research and Medicinal Plants Studies IMPM | Tamze V.,Institute of Medical Research and Medicinal Plants Studies IMPM | Ngono A.R.N.,University of Douala | Ayimele G.A.,University of Buea | And 3 more authors.
Phytochemistry Letters | Year: 2012

A comprehensive phytochemical study of the stem bark of Strychnos icaja was done for the first time and led to the isolation of two new monoindole alkaloids 15-hydroxyvomicine (1) and 12-methoxyicajine (2) along with 13 known alkaloids: the monoindoles N-methyl-sec-iso-pseudostrychnine (3), vomicine (4), icajine (5), 19,20-α-epoxy-12-methoxyicajine (6), 19,20-α-epoxy-12, 15-dihydroxy-11-methoxyicajine (7), 19,20-α-epoxy-15-hydroxynovacine (8), 15-hydroxyicajine (9), 12-hydroxystrychnine (10), strychnine (11) and the tertiary bisindoles sungucine (12), isosungucine (13), strychnogucine C (14) and bisnordihydrotoxiferine (15). Apart from 10 and 11, the other alkaloids were isolated for the first time from the stem bark of this plant. The hemisynthetic derivative, N b-chloromethosungucine (16) and the previously reported synthetic compound 3 were isolated from a natural source for the first time. Fractions and some isolated compounds were tested against the chloroquine-sensitive 3D7 strain of Plasmodium falciparum. The bisindole alkaloids were most active with IC 50 ranging from 0.72 to 3.41 μg/ml whilst the monomers 1 and 3 were slightly active (IC 50 39.92 and 40.27 μg/ml respectively) and 6 inactive. The structures of the compounds were determined based on the analysis of their spectral data. The full 1H and 13C NMR data of compounds 3, 6 and 7 are also reported in the present work for the first time. © 2011 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.

Tsouh Fokou P.V.,University of Ghana | Tsouh Fokou P.V.,University of Yaounde I | Nyarko A.K.,University of Ghana | Appiah-Opong R.,University of Ghana | And 5 more authors.
Journal of Ethnopharmacology | Year: 2015

Abstract Ethnopharmacological relevance Buruli ulcer (BU) is the third most common mycobacterial infection in the world, after tuberculosis and leprosy and has recently been recognized as an important emerging disease. This disease is common in West Africa where more than 99% of the burden is felt and where most affected people live in remote areas with traditional medicine as primary or only option. Reports indicate that the ethnopharmacological control approach of the disease in such settings has shown promise. However, no or very few compilations of traditional knowledge in using medicinal plants to treat BU have been attempted so far. This review aimed to record medicinal plants used traditionally against BU in three countries in West Africa: Ivory Coast, Ghana and Benin and for which ethnopharmacological knowledge supported by pharmacological investigations has been reported. The information recorded in this review will support further pharmacological research to develop appropriate drugs for a better BU control. Material and methods A systematic review of the literature on ethnobotanical use and anti-BU activity of plants reported for BU treatment was performed. The approach consisted to search several resources, including Technical Reports, Books, Theses, Conference proceedings, web-based scientific databases such as publications on PubMed, Science direct, Springer, ACS, Scielo, PROTA, Google and Google scholar reporting ethnobotanical surveys and screening of natural products against Mycobacterium ulcerans. This study was limited to papers and documents published either in English or French reporting ethnopharmacological knowledge in BU treatment or pharmacological potency in vitro. This review covered the available literature up to December 2014. Results The majority of reports originated from the three most affected West African countries (Cote d'Ivoire, Ghana and Benin). Though, 98 plant species belonging to 48 families have been identified as having anti-BU use, many have received no or little attention. Most of the pharmacological studies were performed only on 54 species. To a lesser extent, ethnopharmacological knowledge was validated in vitro for only 13 species. Of those, seven species including Ricinus comminus, Cyperus cyperoides (cited as Mariscus alternifolius), Nicotiana tabacum, Mangifera indica, Solanum rugosum, Carica papaya, and Moringa oleifera demonstrated efficacy in hospitalised BU patients. Four isolated and characterized compounds were reported to have moderate bioactivity in vitro against M. ulcerans. Conclusions This review compiles for the first time ethnopharmacologically useful plants against BU. The phamacological potential of 13 of them has been demonstrated in vitro and support BU evidence-based traditional medicines. In addition, 7 species showed activity in BU patients and have emerged as a promising source of the traditional medicine for treatment of BU. Yet, further safety and efficacy study should be initiated prior any approval as alternative therapy. Overall, a huge gap in knowledge appeared, suggesting further well-planned and detailed investigations of the in vitro, in vivo, and safety properties of the claimed anti-BU plants. Therefore, plants with medicinal potential should be scrutinized for biologically active compounds, using bioassay-guided fractionation approach to provide new insights to find novel therapeutics for BU control. © 2015 Published by Elsevier Ireland Ltd.

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.

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.

PubMed | Institute of Medical Research and Medicinal Plants Studies IMPM, Merck And Co., Autonomous University of Barcelona and University of Liège
Type: Journal Article | Journal: Journal of natural products | Year: 2015

A recently developed NMR method to simultaneously obtain both long-range heteronuclear correlations and carbon multiplicity information in a single experiment, ME-selHSQMBC, is demonstrated as a potentially useful technique for chemical shift assignment and structure elucidation of natural products presenting complicated NMR spectra. Carbon multiplicities, even for C/CH2 and odd for CH/CH3 resonances, can be distinguished directly from the relative positive/negative phase of cross-peaks. In addition, connectivity networks can be further extended by incorporating a TOCSY propagation step. Staurosporine (1) and sungucine (2) are utilized as model compounds to demonstrate these techniques.

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