Three new polyphenols from the rhizomes of Arachniodes exilis

Three new polyphenols, araspidin BB (1), arachniodesin A (2) and arachniodesin B (3), together with two known compounds, epicatechin (4) and procyanidin B-2 (5), were isolated from the rhizomes of Arachniodes exilis. The structures of three new compounds were elucidated as 5-methyl-methylene-bis-phlorobutyrophenone (1), 4beta-ethoxycarbonylmethylepicatechin (2) and epicatechin-(4beta --> 8)-4beta-ethoxycarbonylmethylepicatechin (3), on the basis of their spectral analysis and by comparing them with the related model compounds. Compounds 4 and 5 were obtained from the title plant for the first time.