[Chemical constituents from roots of Pieris formosa and their bioactivity].

By the means of chromatographic methods and spectroscopic evidences, 7 diterpenoids were isolated and identified from the roots of Pieris formosa. These known compounds are elucidated as secorhodomollolide C(1), pierisoid B (2), secorhodomollolide B (3), secorhodomollolide A (4), pierisformotoxin G (5), pierisformotoxin B (6) and pierisformotoxin A (7). Compounds 3, 4 were obtained from this plant for the first time. The analgesic activities of compounds 1-7 were evaluated using an acetic acidinduced writhing test in mice. Compounds 3, 4, 6, and 7 exhibited significant analgesic activity at 5 mg·kg;⁻ (ip) compared to vehicle-injected mice (P<0.05). The writhe inhibition rates of compounds 3, 4, 6 and 7 at 5 mg·kg⁻¹ (ip) were 41.3%, 39.4%, 38.6% and 37.5%, respectively.