[摘要]：Five pentacyclic triterpenoids (1-5) and a sterol (6) were isolated from the stem-bark of Styrax japonica. The six compounds, 1-6, were determined to be 3 beta-acetoxy-28-hydroxyolean-12-ene (1), 3 beta-acetoxyolean-12-en-28-acid (2), 3 beta-acetoxyolean-12-en-28-aldehyde (3), 3 beta-acetoxy-17 beta-hydroxy-28-norolean-12-ene (4), taraxerol (5) and stigmasterol (6), respectively, by spectroscopic means, including the 2D-NMR technique. Compound 4 is a newly discovered natural compound. The protein tyrosine phosphatase 1B (PTP1B) inhibitory activities of the isolated compounds (1-6) were determined in vitro. Among the isolated compounds, 3 beta-acetoxyolean-12-en-28-acid (2) and 3 beta-acetoxyolean-12-en-28-aidehyde (3) had the most potent inhibitory PTP1B activity, with IC50 values of 7.8 and 9.3 gm, respectively. Copyright (C) 2008 John Wiley & Sons, Ltd.
