Evaluation of anti-HCV activity and SAR study of (+)-lycoricidine through targeting of host heat-stress cognate 70 (Hsc70)

The anti hepatitis C virus (HCV) activity of (+)-lycoricidine (1) was evaluated for the first time in this letter, yielding an EC50 value of 0.55 nmol/mL and an selection index (SI) value of 12.72. Further studies indicated that 1 induced this effect by down-regulating host heat-stress cognate 70 (Hsc70) expression. In addition, 20 derivatives were designed and synthesised to investigate the basic structure-activity relationship (SAR) of the title compound. Several of these derivatives exhibit a good inhibition of HCV, such as compound 3 (EC50 = 0.68 nmol/mL, SI = 33.86), compound 2d (EC50 = 15 nmol/mL, SI = 12) and compound 5 (EC50 = 33 nmol/mL, SI >10.91). Meanwhile, the experimental data suggest that the modification of certain groups of (+)-lycoricidine can reduce the cytotoxicity of the compounds.