Leishmanicidal activity of Yucatecan medicinal plants on Leishmania species responsible for cutaneous leishmaniasis.

The leishmanicidal activity of 15 extracts and 4 pure metabolites obtained from Urechites andrieuxii, Colubrina greggii, Dorstenia contrajerva, and Tridax procumbens was evaluated using the newly developed MTS ({3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt) assay, optimized for promastigotes of Leishmania major, Leishmania tropica, and Leishmania aethiopica, as well as for L. aethiopica axenic amastigotes. The assay was then used for calculating the percentage of viable stationary phase parasites after a 24-hr treatment with each plant extract or pure metabolite. The 3 most active samples, 2 from C. greggii (NCG-5C and DCG-3A) and 1 from T. procumbens (TPZ-2A), showed LD50 values of 62.4, 7.2, and 18.5 microg/ml, respectively, on stationary promastigotes, and of 94.2, 27.1, and 95.2 microg/ml, on amastigotes of L. aethiopica. Moreover, TPZ-2A and DCG-3A significantly reduced the percentage of infected monocyte-derived macrophages (THP-I). The percentage of infected cells decreased from 69.9% +/- 2.5% to 20.8% +/- 2% when the cells were treated with the DCG-3A fraction and to 14.9% +/- 0.5% when treated with TPZ-2A, without significantly decreasing the number of human cells. These findings indicate the presence of potentially bioactive metabolites in the roots of C. greggii and in T. procumbens and reflect the importance of pursuing the bioassay-guided purification of these metabolites.

Antibacterial activity of plants used in traditional medicines of Ghana with particular reference to MRSA.

ETHNOPHARMACOLOGICAL RELEVANCE: : In an ethno botanical survey carried out in the Akwapim-North district of the Republic of Ghana, 25 plant species, used in traditional medicine to treat skin disease and/or to treat antimicrobial (viral, bacterial or protozoan) infections were identified. AIM OF STUDY: : To investigate the antimicrobial activity of traditional Ghanaian medicines with special interest in anti-methicillin-resistant Staphylococcus aureus (MRSA) activity. MATERIALS AND METHODS: : Chloroform, ethanol and aqueous extracts (including use of a Stomacher) of these plants were prepared and agar-well diffusion tests, MIC's and MBC's were used to investigate antimicrobial activity. RESULTS: Extracts of 13 plant species inhibited the growth of one or more of the following bacteria: MRSA, methicillin-sensitive Staphylococcus aureus (MSSA), Streptococcus pyogenes, Escherichia coli, Pseudomonas aeruginosa and Proteus vulgaris. Extracts from 11 of these 13 plant species also inhibited the growth of three or more of 14 additional clinical isolates of MRSA. Aqueous extracts of Alchornea cordifolia were active against all 21 bacterial strains tested and showed the highest levels of antibacterial activity overall with MIC's against MRSA in the range of 1.6-3.1 mgml(-1) and MBC's in the range of 6.3-12.5 mgml(-1). CONCLUSIONS: : The presence of antibacterial activity in extracts of Elaeophorbia drupifera, Rauwolfia vomitoria and the leaves of Solanum verbascifolium, plants traditionally used to treat skin infections, are reported for the first time. Extracts from Alchornea cordifolia, also used to treat wounds, had the widest spectrum of antibacterial activity.