In-vitro virucidal and virustatic anti HIV-1 effects of extracts from Persea americana Mill. (avocado) leaves

Aqueous (PA1) and methanolic extracts (PA2a-d; PA3) from the tropical tree Persea americana Mill. (Lauraceae), were evaluated for their cellular toxicity and anti-HIV-1 activity both in virustatic and virucidal assays. With the exception of PA3 and PA2d, all extracts showed anti-HIV-1 activity at concentrations which were not toxic for the H9 indicator cells. From the methanol insoluble extract (PA2) four different fractions (PA2a-d) were obtained using reverse-phase column chromatography, and two of the fractions (b and c) showed detectable virucidal effect. One fraction (PA2a) showed virustatic effects inhibiting HIV syncytium formation and Viral p24 antigen formation at concentrations which were not toxic for the indicator cells. The results demonstrate for the first time that extracts from P. americana leaves have moderate anti-HIV-1 activity in vitro.