THE CHEMICAL CONSTITUENTS OF BAI-HUA-QIAN-HU, THE ROOT OF PEUCEDANUM PRAERUPTORUM DUNN. (UMBELLIFERAE)——FOUR NEW COUMARINS

The ether or petr. ether extract of the root of Peucedanum praeruptorum Dunn. afforded four coumarins: (±)-praeruptorin A (Ⅰ), (±)-praeruptorin B (Ⅱ), (+)-praeruptorin A (Ⅲ), and (+)-praeruptorin B (Ⅳ). (Ⅰ) and (Ⅱ) were the racemates of (Ⅲ) and (Ⅳ), respectively.The structures of (Ⅲ) and (Ⅳ) were elucidated as 3'(S)-angeloyloxy-4' (S)-acetoxy-3', 4'-dihydroseselin and 3'(S), 4'(S) -diangeloyloxy-3', 4'-dihydroseselin, respectively. (Ⅲ) was an antipode of isopteryxin and (Ⅳ) was an antipode of anomalin.Besides, mannitol was also isolated and nodakenin (Ⅴ) was detected by paper chromatography.(Ⅲ) and its dihydroderivative (ⅩⅥ) were found to increase coronary blood flow on isolated guinea pig heart.