Medicinal Foodstuffs. XX. Vasorelaxant Active Constituents from the Roots of Angelica furcijuga Kitagawa: Structures of Hyuganins A, B, C, and D

摘要

From the methanolic extract with vasorelaxant activity obtained from Angelica furcijuga Kitagawa, four new khellactone-type coumarins, hyuganins A, B, C, and D, were isolated together with twelve known coumarins, two known acetylenic compounds, and a known lignan. The structures of hyuganins A, B, C, and D were determined on the basis of chemical and physicochemical evidence. Nine principal coumarins (hyuganin A, anomalin, pteryxin, isopteryxin, isoepoxypteryxin, praerosides II and IV, apiosylskimmin, (R)-peucedanol 7-O-β-D-glucopyranoside), two acetylenic compounds [(-)-falcarinol and falcarindiol], and related compounds were examined for inhibitory activities on high concentration of K~+ (High K~+)- and dl-norepinephrine (NE)-induced contractions. The results indicate that the 3'- and 4'-acyl groups of khellactone-type coumarins are essential for the inhibitory activity on the contractions by High K~+. Hyuganin A and anomalin showed inhibitory effects on High K~+-induced contraction, but not on NE-induced contraction. Other active coumarins (pteryxin, isopteryxin, isoepoxypteryxin) and an acetylenic compound (falcarindiol) non-selectively inhibitted both contractions by High K~+ and NE.