ISSN 2169-303X
International Journal of Medicinal Plants Research ISSN 2169-303X Vol. 7 (8), pp. 407-409, August, 2018. © International Scholars Journals
Full Length Research Paper
A study of the biological activity of methanol extracts of some medicinal plants from South Africa
Pascal O.Bessong1*, Luis B. Rojas2, Larry C. Obi1, Peter M. Tshisikawe3 Eunice O. Igunbor4
1Department of Microbiology, University of Venda, Thohoyandou, South Africa
2Laboratoire de Chimie des Substances Végétales, Centre de Recherche en Chimie Moléculaire, Université de Bordeaux 1, and Instituto de Investigaciones, Facultad de Farmacia, Universidad de Los Andes, Venezuela.
3Department of Biological Sciences, University of Venda, Thohoyandou, South Africa.
*Corresponding author. E-mail: [email protected]. Tel: +27 15 962 8301. Fax: +27 15 962 4749.
Accepted 07 August, 2017
Abstract
The use of medicinal plants for AIDS- related conditions is common in South Africa. In order to establish an antiviral rationale for the use of these plants we screened fractions of the methanol extracts of medicinal plants for activity against HIV-1 reverse transcriptase (RT) and integrase (IN). The n-butanol fraction obtained from the crude methanol extracts of the roots of Bridelia micrantha (Hochst) Baill. (Euphorbiaceae) was observed to be as the most active inhibiting the RNA-dependent-DNA polymerization (RDDP) activity of HIV-1 RT with an IC50 of 7.3 g/ml. However, it had no activity on the 3’-end processing activity of HIV integrase. Bioassay-guided fractionation of the n-butanol fraction yielded friedelin and -sistosterol, which did not inhibit the RDDP of RT or 3’-end processing functions of IN even at a concentration of 500 M. An uncharacterized fraction obtained in the bioassay-guided fractionating process inhibited the RDDP with an IC50 of 9.6 g/ml, but had no inhibition on IN. Phytochemical screening indicated the presence of flavonoids and tannins in the uncharacterized fraction.
Key words: HIV-1; reverse transcriptase; integrase; medicinal plants; inhibition; Venda; South Africa.