Two 22S-solanidine-type steroidal alkaloids from Fritillaria anhuiensis.

Phytochemical investigation of the fresh bulbs of Fritillaria anhuiensis S. C. Chen et S. E. Yin, resulted in the isolation of a known steroidal alkaloid solanidine of (22S,25S)-solanid-5-en-3beta-ol (1), which has never yet been found as a natural substance, and of a new steroidal alkaloid (22S,25S)-solanid-5,20(21)-dien-3beta-ol. Compounds 1 and 2 were the first solanidine-type alkaloids with 22-S configuration discovered from nature. Their structures were elucidated based on spectroscopic analysis, including 1D and 2D NMR experiments.