A. (5R,5aR,8aR,9S)-9-[(4,6-O-(R)-ethyliden-β-D-glukopyranosyl)oxy]-5-{4-[(benzyloxykarbonyl)oxy]-3,5-dimethoxyfenyl}-5,8,8a,9-tetrahydroisobenzofuro[5,6-f][1,3]benzodioxol-6(5aH)-on (4 ˊ-karbobenzoyloxyethylidenlignan P),