Total synthesis and anti-viral activities of an extract of Radix isatidis.

Radix isatidis (Banlangen), a famous traditional Chinese medicine, has been used for thousands of years in China due to its anti-viral activity. Through our research, we inferred that the anti-viral activity of Radix isatidis depended on the water-soluble part. Among the components of this extract, the isoquinoline derivative 1 was isolated for the first time and has shown better anti-viral activity than other constituents. In this study, to solve the problem of sourcing sufficient quantities of compound 1, a total synthesis route is described, and several analogues are also evaluated for their anti-viral activities. Among them, compound 8 shown potent anti-viral activity with an IC50 value of 15.3 µg/mL. The results suggested that isoquinoline derivatives possessed potent anti-viral activity and are worthy further development.