Avaliação da atividade antirretroviral de produtos naturais

Abstract

This study aimed to evaluate the antiretroviral activity of natural products. Initially implemented the cell culture for cytotoxicity tests and some tests of antiviral activity. Were selected based on pre-existing data in the literature of antiviral activity in the genus or family under study and also in a chemotaxonomic approach, 39 extracts (from 12 plant families and four families of Brazilian algae) and 11 pure compounds from the group of quinones and terpenes. All were evaluated for cytotoxicity in order to find a concentration with low cytotoxicity for testing antivirals ( 50%). Cytotoxicity was evaluated by the methods of Trypan Blue exclusion and MTT reduction. The evaluation of antiviral activity was done by two methods: research on the inhibition of cytopathic effects (ECPs) characteristic of retroviruses (syncytium and lysis) using maedi visna virus which is a model in vitro and in vivo of the HIV, and inhibition of activity of reverse transcriptase (RT) of HIV-1. The activity of RT HIV-1 was measured by a colorimetric method quantitative immunoassay (Reverse Transcriptase Assay, Roche , Germany). Was first tested an extract of each plant species on the potential antiviral activity, and when it showed some activity other extracts of the same species were tested. Efavirenz was used as control and showed antiviral inhibition of CPE and TR of 75 and 98%, respectively, at a concentration of 1 μg/mL. Among the pure compounds the best results were those of emotinas D and F, which also inhibit the ECPs in 37.5 and 25% were 24.4 and 20.5% inhibition of TR, respectively, 1 μg/mL. Among the tested plants found seven with inhibitory activity of HIV-1 RT. Among these we find a plant whose activity was very high in the crude extract when compared with control efavirenz and has been even greater in isolated fractions. The crude extracts of leaves (50 μg/mL) and stem bark (100 μg/mL) showed 98 and 67% inhibition of TR, respectively. The acetate (50 μg/mL) and chloroform (100 μg/mL) fractions of the latter, showed 95 and 89% of inhibition, respectively. Our results suggest that we have strong candidates for to combat the HIV that may present as a rich source of inhibitors of RT.