Two Novel Flavonoids and Cytotoxicity Evaluation from Cryptocarya yunnanensis.

Two new flavonoids, cryunchalcone (1) and cryptoyunnanone I (2), were isolated from the leaves and twigs of Cryptocarya yunnanensis. Their structures were elucidated by the detailed spectroscopic data analysis and electronic circular dichroism (ECD) calculations. Cryunchalcone (1) is a biflavonoid constructed by a dihydrochalcone coupled with a chalcone through an unprecedented C-2''-C-6 linkage. Cryptoyunnanone I (2) is a unique complex flavanone bearing a phenylpropanoid moiety.