Novel sesquiterpenes and norergosterol from the soft corals Nephthea erecta and Nephthea chabroli

摘要

Chemical investigations on the acetone extract of the Formosan soft coral Nephthea erecta have afforded a new calamenene-type sesquiterpene with a mercaptan group at C-15,erectathiol(1),and a previously reported sesquiterpenoid,(+)-trans-calamenene(2).A novel sec-germacrane sesquiterpene(3),along with a novel norergosterol,chabrosterol(4),possessing a 19-norergostane skeleton,was isolated from the other soft coral Nephthea chabroli.The structures of these metabolites were elucidated through extensive spectroscopic analyses.In vitro anti-inflammatory activity of 1 and 4(10 mu M)significantly reduced the levels of the iNOS protein(58.0 ±6.5% and 12.4 ±2.9%)and COX-2 protein(108.7 ±4.5% and 45.2 ±5.4%).In addition,metabolite 1(166 ug/disk)exhibited antimicrobial activities against a small panel of bacterial strains.