Abstract
A new cyclic diarylheptanoid namely alnuheptanoid B (3), along with four known cyclic diarylheptanoids: myricanone (1), (+)-S-myricanol (2), myricanone 5-O-beta-D-glucopyranoside (4), and (+)-S-myricanol 5-O-beta-D-glucopyranoside (5) were isolated from the EtOAc fraction of Alnus japonica Steud (family: Betulaceae) stem bark. Their structures were established by different spectroscopic analyses, as well as optical rotation measurement. Compounds 1, 2, 4, and 5 are isolated for the first time from A. japonica. The antioxidant and anti-inflammatory activities of compounds (1-5) were assessed using DPPH assay and carrageenin induced rat paw edema model, respectively. They displayed significant antioxidant activity in relation to propyl gallate (standard antioxidant) at concentration 50 mu M. Compound 2 demonstrated antiinflammatory effect at a dose 10 mg/kg compared with indomethacin (positive control).