Antimicrobial, antiviral and cytotoxic activity of extracts and constituents from Polygonum spectabile Mart.

Polygonum spectabile is used in Brazil for treatment of several infection diseases. Extracts and constituents isolated from this species were evaluated for cytotoxicity and effects on 15 bacterias and yeasts as well on 4 viruses strains (HHV-1, VACV-WR, EMCV, DEN-2). Less polar extracts were effective against Staphylococcus aureus, Bacillus subtillis, Micrococcus luteus, M. canis and Tricophyton mentagrophytes and T. rubrum. Two known chalcones and 3-O-β-d-glucosyl-β-sitosterol were isolated. The ethanol extract was the only one to show antiviral activity (CE50 < 30 μg/ml). One chalcone has inhibited the growth of several bacteria and was significantly active against dermathophytes. The 3 compounds isolated have shown moderate cytotoxicity against Vero and LLCMK2 cells (CC50 <50 μg/ml). These results support the use of P. spectabile as antimicrobial agent.