[Flavonoids of Cuscuta australis R. Br].

Six flavonoids were isolated from the seed of Cuscuta australis and four of them were identified as kaempferol, quercetin, astragalin and hyperoside. Hyperoside was obtained from this plant for the first time. In comparison with the flavonoids in C. chinensis, it is found that quercetin and its glycoside are the main flavonoids in C. australis. This result suggests that the flavonoids can be used to distinguish these two medicinal materials.