Complex Flavanones from Cryptocarya metcalfiana and Structural Revision of Oboflavanone A.

Nine new complex flavanones, cryptometcones A-I ( 1 - 9 ), along with four known analogues, were isolated from Cryptocarya metcalfiana . The structures of 1 - 9 including their absolute configurations were elucidated by spectroscopic data analysis and electronic circular dichroism (ECD) calculations. In addition, the structure of oboflavanone A was revised, while the absolute configurations of oboflavanone B, cryptoflavanone C, and cryptoflavanone D were determined, according to their spectroscopic data. Compounds 3 - 5 , 8 , and 9 exhibited cytotoxicity against the HCT-116 cancer cell line.