Structure-activity relationship of flavonoid bifunctional inhibitors against Zika virus infection.

Zika virus (ZIKV) infection is a global public health problem due to its rapid spread and the possibility of causing microcephaly. Currently, no specific antivirals against ZIKV are available for treatment. In the present study, several flavonoids (galangin, kaempferide, quercetin, myricetin and EGCG) were found to reduce ZIKV induced plaques and viral RNA copies with negligible cytotoxic effects on host cells. In addition, inhibition of ZIKV propagation by flavonoids showed structure-activity relationship. Our results demonstrate flavonoids as inhibitors of ZIKV entry and NS2B-NS3 protease. Hence, these flavonoids could be used as potential bifunctional drugs for treating ZIKV infections.