Antiviral activity of Solanum paniculatum extract and constituents.

Solanum species are traditionally employed as antiherpes and anticancer agents in different countries. S. paniculatum has widespread ethnomedical uses in Brazil, including the treatment of viral infections. This paper reports on the isolation of neotigogenin (1) and the new compound delta25(27)-tigogenin-3-O-beta-D-glucopyranoside (2), obtained as a mixture of R and S diastereoisomers at C22 from an ethanol extract of S. paniculatum leaves, along with the determination of their cytotoxicity against Vero cells and antiviral effect against human herpes virus type 1 (HHV-1), murine encephalomyocarditis virus (EMCv), and vaccinia virus strain Western Reserve (VACV-WR). The extract of S. paniculatum inhibited HHV-1 replication [EC50 = (298.0 +/- 11.2) microg/ml] and showed no effect on EMCv and VACV-WR. On its turn, 1 was inactive against the assayed strains but presented high cytotoxicity [CC50 = (2.03 +/- 0.03) microg/ml], whereas 2 exhibited significant antiherpes [EC50 = (170.8 +/- 1.7) microg/ml] and antivaccinia virus effects [EC50 = (177.0 +/- 3.3) microg/ml], with low cytotoxicity (CC50 > 400 microg/ml). The results corroborate Solanum paniculatum as a source of cytotoxic and antiviral compounds.