OBJECTIVETo investigate the effects of Qihong capsule (QH) on HeLa cells infected by coxsackievirus B3 (CVB3) in vitro and its potential antiviral mechanism.

METHODSHeLa cells were infected by CVB3 in vitro. XTT assay and plaque inhibition assay were performed to determine the 50 % effective dose, (ED50), 50 % inhibitory concentration (IC50), and 50% cytotoxicity concentration (CC50) of QH and the control drug, ribavirin. The total therapeutic index (TI) was calculated. Anti-viral time-course experiments were performed to compare the anti-viral effects at different time points. The inhibitory effects of QH on the attachment and penetration of CVB3 were also observed.

RESULTSXTT assay and plaque inhibition assay showed that the ED50 and IC50 were (7.16+/-0.80) mg/L and (2.63+/-0.50) mg/L in QH group and (4.35+/-0.40) mg/L and (1.92+/-0.30) mg/L in ribavirin group, respectively. CC50 was 16-fold higher in QH group than in ribavirin group QH: (1 648+/-219) mg/L vs. Ribavirin: (103+/-14) mg/L. Time-course studies demonstrated that antiviral effect of QH was mainly found 0-4 hours after infection. QH effectively blocked the attachment and penetration of CVB3 into cells.

CONCLUSIONBy inhibiting the attachment and penetration of CVB3, QH can effectively inhibit the invasion of virus in vitro with low toxicity.