HIV-1 pseudovirus neutralisation by a natural compound: a potential microbicide

Abstract

A natural compound isolated from extracts of an indigenous plant in the Eastern Cape, South Africa, indicates neutralisation activity against HIV-1 pseudoviruses. This natural compound can potentially be used in a microbicide as an alternative means to prevent the spread of HIV and AIDS. The compound’s neutralisation activity (IC50 0.05-7.2µg/mL) is comparable with that of the entry inhibitor T-20 (IC50 0.05-2.94µg/mL) and the reverse transcriptase inhibitor Tenofovir (IC50 0.09-0.83µg/mL) when screened against the NIH reference panel for HIV-1 subtype C envelope molecular clones. T20 is a more relevant drug for comparative purposes as it is an entry inhibitor and indications on our compound of interest point to it also acting in a similar manner. The mode of action of the compound is, however, yet to be determined. The aim is to develop a microbicide based on an indigenous plant for people infected with HIV-1. The compound will also be screened against other HIV-1 subtypes to test the neutralisation breadth. The authors have shown that the extracts of the plant and the compound are not cytotoxic towards TZM-bl cells when tested in a MTT assay at concentrations up 100 µg/mL. In addition these did not show any neutralisation activity against VSV-G which has a similar glycoprotein to HIV-1 indicating specificity to HIV-1.