[Chemical constituents from Machilus wangchiana]

Twenty-one compounds were isolated from an ethanol extract of Machilus wangchiana by a combination of various chromatographic techniques including column chromatography over silica gel and Sephadex LH-20 and reversed-phase HPLC. Their structures were identified by spectroscopic data analysis including optical rotation, UV, IR, MS, and NMR data. The compounds are categorized as eight butanolides (1-8), eight lignans (9-16), and five terpenoids (17-21). Compound 16 is a new natural product with an uncommon heptanorlignan skeleton. Meanwhile, the unique Ginkgo biloba (maidenhair) metabolites ginkgolides A (19) and ginkgolides B (20) were obtained from this material. In the preliminary assays, compound 5 showed selective inhibitory activities against human stomach cancer cells (BGC-823) and ovary cancer cells (A2780) with IC50 values of 0.13 x 10(-6) and 2.66 x 10(-6) mol x L(-1), respectively. Compounds 8 and 9, at 1 x 10(-5) mol x L(-1), showed inhibitory activities against the release of beta-glucuronidase of the polymorphous nuclear leukocytes induced by platelet activating factor (PAF), with inhibition rates of 60.0% and 54.2%.