Cytotoxic dihydroagarofuranoid sesquiterpenes from the seeds of Celastrus orbiculatus.

A chemical study on the seeds of Celastrus orbiculatus has led to the isolation of nine new (1- 9) and 13 known dihydro-beta-agarofuran derivatives. The identification and structural elucidation of the new compounds were based on spectroscopic data analysis, and the absolute configurations of compounds 1- 6, 8-10, and 16, as well as derivatives 2a and 6a, were determined by CD studies or by chemical methods. All compounds isolated were evaluated for cytotoxic activity against HL-60 human leukemia cells.