Four new megastigmane glycosides from the leaves of Eucommia ulmoides Oliver

Four new megastigmane glycosides, eucomegastigsides E1 (1), eucomegastigsides E2 (2), eucomegastigsides F1 (3), and eucomegastigsides F2 (4) were isolated from the leaves of Eucommia ulmoides Oliver. Their structures were elucidated based on extensive spectroscopic analysis and their absolute configurations were determined by comparison of experimental optical rotation (OR) to DFT calculations. In addition, compounds 1-4 were evaluated for their...