Anti-HIV activities of the compounds isolated from Polygonum cuspidatum and Polygonum multiflorum.

The 70 % EtOH extract of Polygonum cuspidatum showed inhibitory action against HIV-1-induced syncytium formation at non-cytotoxic concentrations in vitro with a 50 % effective concentration (EC(50)) of 13.94 +/- 3.41 microg/mL. Through bioactivity-guided fractionation, 20 phenolic compounds, including eight stilbenoids, were isolated from the roots of Polygonum cuspidatum, and their anti-HIV-1 activities were evaluated. Results showed that compounds 1, 13, 14, and 16 demonstrated fairly strong antiviral activity against HIV-1-induced cytopathic effects in C8166 lymphocytes at non-cytotoxic concentrations, with EC (50) values of 4.37 +/- 1.96 microg/mL, 19.97 +/- 5.09, 14.4 +/- 1.34 microg/mL, and 11.29 +/- 6.26 microg/mL and therapeutic index (TI) values of 8.12, > 10.02, > 13.89, and > 17.71, respectively. Other compounds showed either weak or no effects. Compound 6 also showed weak inhibition (153.42 +/- 19.25 microg/mL); however, it possesses very good water solubility and showed almost no cytotoxicity (> 2000 microg/mL), therefore achieving a fairly good TI (13.04). The activities of the two compounds (3 and 18) from Polygonum multiflorum were also assayed. The relationship between molecular structures and their bioactivities was also discussed. Georg Thieme Verlag KG Stuttgart-New York.