New vernocuminosides from the stem barks of Vernonia cumingiana Benth

Seven new stigmastane-type steroidal glycosides, vernocuminosides A-G (1-7), have been isolated from the stem barks of Vernonia cumingiana Benth. The structural elucidation and stereochemistry determination were achieved by spectroscopic and chemical methods including ID and 2D NMR (H-1-H-1 COSY, HSQC, HMBC, and NOE) experiments, especially the employment of Snatzke's method expressed by the induced circular dichroism spectra. Anti-inflammatory activities and cytotoxicities of compounds 1-7 were evaluated. (C) 2008 Elsevier Inc. All rights reserved.