title: Evaluation of selected South African medicinal plants for inhibitory properties against human immunodeficiency virus type 1 reverse transcriptase and integrase.
abstract: Seventeen aqueous and methanol extracts from nine South African medicinal plants, ethnobotanically selected, were screened for inhibitory properties against HIV-1 reverse transcriptase (RT). Isolated compounds were additionally evaluated on HIV-1 integrase (IN). The strongest inhibition against the RNA-dependent-DNA polymerase (RDDP) activity of RT was observed with the methanol extract of the stem-bark of Peltophorum africanum Sond. (Fabaceae) (IC(50) 3.5 microg/ml), while the methanol extract of the roots of Combretum molle R.Br. ex G. Don (Combretaceae) was the most inhibitory on the ribonuclease H (RNase H) activity (IC(50) 9.7 microg/ml). The known compounds bergenin and catechin, and a red coloured gallotannin composed of meta-depside chains of gallic and protocatechuic acids esterified to a 1-O-isobutyroly-beta-D-glucopyranose core, were isolated from the methanol extract of the roots and stem-bark of Peltophorum africanum. The gallotannin inhibited the RDDP and RNase H functions of RT with IC(50) values of 6.0 and 5.0 microM, respectively, and abolished the 3'-end processing activity of IN at 100 microM. Catechin showed no effect on RT but had a moderate activity on HIV-1 IN. Bergenin was inactive on both enzymes. The aqueous and methanol extracts were non-toxic in a HeLaP4 cell line at a concentration of 400 microg/ml.
authors.affiliation: Department of Microbiology, University of Venda for Science and Technology, PMB X5050, Thohoyandou 0950, South Africa. pb4j@virginia.edu
authors.forename: Pascal Obong
authors.initials: PO
authors.lastname: Bessong
authors.forename: Chikwelu Larry
authors.initials: CL
authors.lastname: Obi
authors.forename: Marie-Line
authors.initials: ML
authors.lastname: Andréola
authors.forename: Luis B
authors.initials: LB
authors.lastname: Rojas
authors.forename: Laurent
authors.initials: L
authors.lastname: Pouységu
authors.forename: Eunice
authors.initials: E
authors.lastname: Igumbor
authors.forename: J J Marion
authors.initials: JJ
authors.lastname: Meyer
authors.forename: Stéphane
authors.initials: S
authors.lastname: Quideau
authors.forename: Simon
authors.initials: S
authors.lastname: Litvak
mesh_terms: D019380:Anti-HIV Agents / Q000302:isolation & purification* / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D029765:Combretum / Q000737:chemistry; D004279:DNA, Viral / Q000187:drug effects; D000431:Ethanol; D019427:HIV Integrase; D019428:HIV Integrase Inhibitors / Q000302:isolation & purification* / Q000494:pharmacology*; D054303:HIV Reverse Transcriptase; D006801:Humans; D016488:Medicine, African Traditional; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D010946:Plants, Medicinal / Q000737:chemistry*; D018894:Reverse Transcriptase Inhibitors / Q000302:isolation & purification* / Q000494:pharmacology*; D012997:Solvents; D013019:South Africa; D014407:Tumor Cells, Cultured; D014867:Water
chemical_list: D019380:Anti-HIV Agents; D004279:DNA, Viral; D019428:HIV Integrase Inhibitors; D010936:Plant Extracts; D018894:Reverse Transcriptase Inhibitors; D012997:Solvents; D014867:Water; D000431:Ethanol; D019427:HIV Integrase; D054303:HIV Reverse Transcriptase