Antiviral activity of Trichilia catigua bark extracts for herpesvirus and poliovirus.

Herpesvirus and poliovirus are responsible for important diseases in human and animal. Trichilia catigua a Brazilian native plant known as catigua has several medicinal properties among them antimicrobial for bacteria and protozoa, however, no antiviral activity has been reported yet. This study evaluated the antiviral activity of the crude extract (CE) and aqueous and ethyl acetate fractions (AF, EAF) obtained from T. catigua in the replication of the Herpes simplex virus (HSV-1), bovine herpesvirus (BoHV-1) and poliovirus (PV-1). The cytotoxicity was analyzed by MTT assay and the antiviral effect was determined by the addition of extracts (0.25 to 100.0 mu g/ml), before (-2h and -1h), during (0h) and after (1h and 2h) the viral infection, by plaque reduction assay, in HEp-2 cell culture. The virucidal activity and inhibition of viral adsorption were also evaluated. In addition, the combination index (CI) with Acyclovir (ACV - reference drug) was determined for HSV-1. CE, AF and EAF showed a low toxicity (CC50 > 400 mu g/ml) and low inhibitory concentration (IC50), ranging from 2.44-34.25 mu g/ml for herpesvirus and 0.67 to 1.8 mu g/ml for PV-1, associated with high selectivity index. The tested compounds showed high virucidal effect and high ability to inhibit viral adsorption, for all virus. The CI demonstrated a synergic effect (CI<1) for AF and EAF comparatively to acyclovir (ACV). Our study demonstrated that the extract and fractions of T. catigua is promising for future antiviral drug design with economically feasible production.