title: Anti-HIV activities of organic and aqueous extracts of Sutherlandia frutescens and Lobostemon trigonus.
abstract: A screening process was applied to extracts made from Sutherlandia frutescens (L.) R. Br (Fabaceae) and Lobostemon trigonus (Boraginaceae) as identified by the Botany Department, University of Port Elizabeth to detect if any of the extracts inhibited the human immunodeficiency virus (HIV). For purposes of dereplication, sulphated polysaccharides were removed and bovine serum albumin (BSA) was included in the assays to adsorb non-specific tannins potentially present. In the reverse transcriptase (RT) assay, an aqueous extract of the Lobostemon leaves inhibited HIV-1 RT with an IC50 value of 49 microg/ml, while in the protease assay no inhibition was seen. In the alpha- and beta-glucosidase assays, no significant inhibition was seen with the inclusion of BSA, indicating tannin-based inhibitory effects on these two enzymes. The beta-glucuronidase inhibitory activity, however, was retained in the presence of BSA. The study shows that Sutherlandia extracts contain inhibitory compounds active against HIV target enzymes, while aqueous Lobostemon leaf extracts contain a potent HIV-1 RT inhibitor, thus showing a potential mechanistic action of these plants in aiding HIV-positive patients.
authors.affiliation: Department of Biochemistry and Microbiology, University of Port Elizabeth, PO Box 1600, Port Elizabeth, 6000 South Africa.
authors.forename: S M
authors.initials: SM
authors.lastname: Harnett
authors.forename: V
authors.initials: V
authors.lastname: Oosthuizen
authors.forename: M
authors.initials: M
authors.lastname: van de Venter
mesh_terms: D019380:Anti-HIV Agents / Q000737:chemistry / Q000494:pharmacology*; D028082:Boraginaceae; D007887:Fabaceae; D035264:Flowers / Q000737:chemistry; D006026:Glycoside Hydrolases / Q000037:antagonists & inhibitors / Q000737:chemistry; D006678:HIV / Q000187:drug effects* / Q000201:enzymology; D020128:Inhibitory Concentration 50; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D011480:Protease Inhibitors / Q000737:chemistry / Q000494:pharmacology; D018894:Reverse Transcriptase Inhibitors / Q000737:chemistry / Q000494:pharmacology; D014779:Virus Replication / Q000187:drug effects; D014867:Water
chemical_list: D019380:Anti-HIV Agents; D010936:Plant Extracts; D011480:Protease Inhibitors; D018894:Reverse Transcriptase Inhibitors; D014867:Water; D006026:Glycoside Hydrolases