Naphthopyrone and anthraquinone derivatives from Comanthus delicata

Abstract

• Fourteen pigments were isolated from the crinoid Comanthus delicata . • Five new napthopyrone derivatives, delicapyrons A − E ( 1 − 5 ), were elucidated. • 1 and 2 possess novel bisnaphthopyrone structures firstly described to date. • 7 significantly induced apoptosis in SK-Mel-2 cells and increased caspase 3 activity. Five new naphthopyrone derivatives, delicapyrons A − E ( 1 − 5 ), and nine known compounds were isolated from the MeOH extract of the Vietnamese crinoid Comanthus delicata . Their structures were elucidated by spectroscopic methods, including HRQTOFMS and 1D and 2D NMR experiments. The new compounds 1 and 2 possess novel bisnaphthopyrone structures containing linear and angular naphthopyrone units that were linked together via a methylene group and are first described herein. Among the isolated compounds, delicapyron B ( 2 ) exhibited significant and selective cytotoxicity against SK-Mel-2 and MCF7 human cancer cell lines, whereas delicapyron D ( 4 ), comaparvin ( 6 ), 6-methoxycomaparvin ( 7 ), and 5,8-dihydroxy-6,10-dimethoxy-2-methyl-4 H -naphtho[1,2- b ]pyran-4-one ( 8 ) showed this activity against the SK-Mel-2 cell line. In addition, compound 7 significantly induced cell death through apoptosis in SK-Mel-2 cells and increased caspase 3 activity at both 20 and 100 μM.