HIV-1 reverse transcriptase and protease assay of methanolic extracts of Adansonia digitata L

Abstract

Objective: Anti-HIV activity studies of methanolic extracts of Adansonia digitata L. leaves, root bark and fruit pulp. Methods: Methanolic extracts of A. digitata were tested for HIV enzyme inhibitory activity against HIV-1 reverse transcriptase (RT) and HIV-1 protease (PR). HIV-1 RT assay was performed using non-radioactive HIV-RT colorimetric ELISA kit while the HIV-1 PR assay was performed using a fluorogenic octapeptide substrate, HIV-FRET (fluorescence resonance energy transfer) and a recombinant HIV-1 protease solution (AnaSpec Inc., USA). Results: The percentage inhibition of controls and A. digitata leaves, root bark and fruit pulp extracts were calculated relative to uninhibited HIV-1 RT and PR in 2% DMSO. The results of the HIV-1 RT assay indicated 26.5% inhibition by root bark extract (50 µg/ml) and 12.2% inhibition by leaf extract while the fruit pulp extract (100 µg/ml) has shown only 5.9% inhibition as compared to standard Nevirapine (100 nM) 27.5% inhibition. In the case of HIV-protease assay, leaf extract and fruit pulp extract (50 µg/ml) has shown quite high inhibition (≥ 50%) to the extent of 75% and 74% respectively which is very significant. The root bark extract has shown 35% inhibition. Conclusion: Methanolic extract of the leaves, root bark and fruit pulp of A. digitata has shown low anti-HIV-1 RT but significant PR activity. HIV-1 RT activity of root bark extract and HIV-1 PR activity of fruit pulp extract indicates the potential of the plant as an anti-HIV agent.