Inhibitory effect of glycosides like saponin from soybean on the infectivity of HIV in vitro.

Soybean saponins isolated from soybean seeds were investigated for their antiviral activity on HIV in vitro, using an HTLV-I-carrying cell line, MT-4. Saponin B1 completely inhibited HIV-induced cytopathic effects and virus-specific antigen expression 6 days after infection at concentrations greater than 0.5 mg/ml. Saponin B2 also inhibited HIV infection, although less potently. Both saponin B1 and B2 had no direct effect on the reverse transcriptase activity of HIV. Saponin B1 also inhibited HIV-induced cell fusion in the MOLT-4 cell system. The results of this study suggest that soybean saponins, especially saponin B1, have inhibitory activity against HIV infection.