Investigation of some Hypericum species native to Southern of Brazil for antiviral activity

Three plant species, Hypericum connatum, Hypericum caprifoliatum, Hypericum polyanthemum (Guttiferae), growing in Southern of Brazil were chemically i nvestigated and tested for their antiviral activity against feline immunode ficiency virus (FIV). The chemical analysis revealed the presence of polyph enolic compounds such as tannins and flavonoids. Hypericin was not detected in these species. The aqueous extract (AE), the aqueous extract with low t annin concentration (LTCAE) and the methanolic extract (ME) were tested for their cytotoxic properties in concentrations of 50-150 mug/ml. AE was toxi c to CRFK for the three species in all concentrations. LTCAE and ME varied between different concentrations being not toxic or allowing 80% of cell gr owth. LTCAE and ME (10-50 mug/ml) were analyzed for antiviral activity by i nhibition of CPE and measuring FIV genome from cell culture supernatant. LT CAE of all species in this work did not cause any inhibition of FIV. Althou gh no difference was seen in CPE, a lower number of viral particles in the supernatant was observed when FIV infected cells were treated with ME of H. connatum. These results suggest that some plants of the genus Hypericum fr om Southern Brazil contain compounds with potential antiviral activity agai nst lentiviruses. (C) 2001 Published by Elsevier Science Ireland Ltd.