Isolation and identification of flavonoids from Coreopsis lanceolata L. petals.

The methanol extract of Coreopsis lanceolata L. petals was acid-hydrolysed, and 7,3',4'-trihydroxy-8-methoxyflavanone (1) and 6,3',4'-trihydroxy-7-methoxyaurone (leptosidin) (2) were successfully isolated. The structure of compound 1 is designated to flavanone based on X-ray crystallographic analysis and NMR spectroscopic analysis. Compound 1 showed high-antioxidant effects based on diphenylpicrylhydrazyl radical scavenging assay (94.3% scavenging rate) and superoxide dismutase-like activity assay (23.9% inhibition rate).