Sho-saiko-to (Xiao-Chai-Hu-Tang) and crude saikosaponins inhibit hepatitis B virus in a stable HBV-producing cell line

To search for an effective antiviral agent, this study tested the hypothesis that shosaiko-to (Xiao-Chai-Hu-Tang) and crude saikosaponins possess the activity directly against HBV and could affect the expressions of viral antigens, HBeAg and HBsAg, in HepG(2) 2.2.15 cell model. The viral amount and viral antigens in the suspension were estimated by quantitative real time PCR and enzyme-linked immunosorbent assay (ELISA), respectively. The results showed that sho-saiko-to could inhibit the production of HBV (p < 0.0001), 20 mu g/ml shosaiko-to was efficacious at day-3 of treatment and 10 mu g/ml at day-6. The calculated IC50 and CC50 of sho-saiko-to were 55.76 mu g/ml and 372 mu g/ml, respectively, with a selectivity index of 6.67. Crude saponin of B. chinense could also inhibit the replication of HBV (p < 0.0001). Owing to the anti-neoplastic activity of sho-saiko-to and saikosaponin, their calculated CC50 and selectivity index might be under-estimated. Sho-saiko-to also decreased the expression of HBeAg with the minimal effective concentration of 20 mu g/ml. Sho-saiko-to contained too little saikosaponin. Therefore, the anti-HBV activity of sho-saiko-to might not be mediated by saikosaponin. Sho-saiko-to could be supplementary to nucleotide analogues to minimize the recurrence of viremia after its discontinuation.