In Vitro Anti-Infective Screening Of Selected West African Medicinal Plants

Individual or whole parts of Persea Americana, Caesalpinia bonduc and Caesalpinia pulcherrima have been traditionally used for the treatment of various infectious diseases in West Africa. Methanolic extracts and fractions of these plants were screened for in vitro activity against L. donovani (promastigotes, axenic amastigotes and intracellular amastigotes in THP1 cells), T. brucei, Plasmodium falciparum (chloroquine sensitive and chloroquine resistant strains) and selected pathogenic microbes. With IC₅₀ values less than 10 µg/mL, the extracts exhibited selective antileishmanial activity against, L. donovani Amastigote, and less potent effects against L. donovani Promastigote, L. donovani Amastigote + THP, and T. brucei blood stage trypamastigotes. Fractions of P. Americana and C. pulcherrima showed strong activities against both chloroquine-sensitive and chloroquine-resistant strains of P. falciparum. With IC₅₀ values ranging from 3.6 to 12 µg/mL, all fractions of C. pulcherrima exhibited significant antimicrobial activity especially against C. glabrata, C. krusei, S. aureus and P. aeruginosa (IC₅₀ < 8 – 81 µg/mL). Crude extracts of P. Americana showed activity against C. glabrata, S. aureus and P. aeruginosa (IC₅₀ 22 – 86 µg/mL). These findings are important scientific support for traditional uses of these plants in infectious diseases and provide a strong basis for further studies towards anti-infective drug discovery from the plants.

Acknowledgements: This work was in part supported by USAID/HED grant 153 – 6200BF A-15 – 01 to Prof A. Falodun, University of Benin.