Antiviral stereoisomers of 3,5-bis(2-hydroxybut-3-en-1-yl)-1,2,4-thiadiazole from the roots of Isatis indigotica

Abstract

Abstract Four stereoisomers of 3,5-bis(2-hydroxybut-3-en-1-yl)-1,2,4-thiadiazole, named insatindigothiadiazoles A–D ( 1a – 1d ), were isolated from the roots of Isatis indigotica . Their structures were determined by spectroscopic analysis; specifically, the absolute configurations were assigned by using the MPA determination rule based on Δ δ RS values of MPA esters, and supported by electronic CD (ECD) calculations. Proposed biosynthetic pathways and preliminary investigations of the biological activities of 1a – 1d against influenza virus A (H3N2), Coxsackie virus B3, and/or HSV-1 are also discussed.