Structural basis of antiviral activity of caffeic acid against severe fever with thrombocytopenia syndrome virus

Abstract Caffeic acid (CA), a coffee-related natural compound, has various beneficial biological effects, including antiviral effects. Our former studies demonstrated that the CA dose-dependently inhibited in vitro infection with Dabie bandavirus, which was previously named as severe fever thrombocytopenia syndrome virus (SFTSV), mainly at step of attachment. Therefore, we studied structural basis for conferring anti-SFTSV activity to clarify mechanism action against SFTSV. In this study, nine analogs were examined. The treatment SFTSV 3,4-dihydroxyhydrocinnamic (DHCA) well in dose-dependent manner, whereas other did not. Both and DHCA only possessed o-dihydroxybenzene backbone. When treated catechol (o-dihydroxybenzene), also inhibited. Additionally, four compounds having backbone; phenethyl ester, methyl CA, 3,4-dihydroxyphenylacetic acid, 3,4-dihydroxybenzoic viral infection, although these more toxic or less effective than CA. conclusion, backbone its critical structure activity. Based on findings, modifications residues might improve effect cytotoxicity