Comparative evaluation of cytotoxicity, antiviral and antioxidant activities of different soyasapogenols from soybean saponin

Objectives
The aim of this study was to evaluate comparative and structure–activity relationships of cytotoxicity, antiviral and antioxidant activities of soyasapogenols A, B, D and F (SSA, SSB, SSD and SSF) together against the total soyasaponin extract (TSSE) itself.
Methods
The cytotoxicity of soyasapogenols and TSSE against human colon carcinoma cell line (HCT-116), liver carcinoma cell line (Hep-G2), human breast carcinoma cell line (MCF-7) and normal human melanocytes (HFB-4) cell lines was assessed using sulforhodamine B assay. Their antiviral activities were investigated against Rift Valley fever virus (RVFV), hepatitis C virus model (vesicular stomatitis virus, VSV), and hepatitis A virus (HAV). The antioxidant activity of soyasapogenols and TSSE was assessed using a stable DPPH free radical.
Results and conclusion
The results obtained showed that both TSSE and soyasapogenols have a potent cytotoxic effect on Hep-G2, HCT-116, MCF-7 and HBF-4 cell lines in a concentration-dependent manner. SSA and SSF showed the highest cytotoxic activities against tested cell lines. Analysis of the three-dimensional structure of the measured soyasapogenols indicated that if the β-hydroxyl group at C-21 or C-22 was aligned with the plane of the molecule, a marked increase in the cytotoxic activity of the soyasapogenol was produced. Their antiviral activities against RVFV, VSV and HAV showed significant inhibition activities compared with both TSSE and interferon. SSB showed the best activity against RVFV and HAV, whereas SSA was the best inhibitor against VSV. It was concluded that the hydroxylation at C-21 as well as the presence of a double bond in ring D might enhance anti-VSV activity, whereas they may not be essential for anti-RVFV and anti-HAV activities. On the other hand, the tested soyasapogenols and TSSE did not show good antioxidant activities.