A New Alkaloid with Tracheal Relaxant Effect from the Bulbs of Fritillaria pallidiflora.

A new isosteroidal alkaloid, yibeinone E ( 1), along with five known ones, zhebeinone 3-O-β-D-glucoside ( 2), sinpeinine A ( 3), yubeinine ( 4), ebeinone ( 5), and delavinone ( 6), were isolated from the bulbs of Fritillaria pallidiflora. Their structures were confirmed on the basis of extensive spectroscopic analysis or comparison with the data in the literature (known compounds). Compound 3 showed an apparent relaxation effect on isolated tracheas. [ABSTRACT FROM AUTHOR]