A previously undescribed coumarin and a new coumarino-lignan, together with
the known compounds scopoletin and cleomiscosins A, C, and D, have been is
olated from the root bark of Hibiscus syriacus, and their structures were a
ssigned on the basis of various spectral studies. The coumarin analogue and
scopoletin inhibited monoamine oxidase with moderate IC50 values. The new
coumarino-lignan and cleomiscosin C showed lipid peroxidation inhibitory ac
tivity comparable to vitamin E.