New acyclic diterpenoids from the fruits of Aphanamixis grandifolia and structure revision of nemoralisin B

Four new acyclic diterpenoids (i.e., nemoralisin B (1) and nemoralisins H-J (2-4)) along with three known acyclic diterpenoids (i.e., nemoralisin, nemoralisin A, and nemoralisin D) were isolated from the fruits of Aphanamixis grandifolia. Their structures were determined by extensive spectroscopic studies using NMR spectroscopy and mass spectrometry. In addition, the structure of nemoralisin B has been revised from the previously reported a,beta-unsaturated delta-lactone structure to an a,beta-unsaturated glactone one. Nemoralisin J (4) exhibited moderate inhibitory activity against lipopolysaccharide-induced nitric oxide production in RAW 264.7 cells with an IC50 value of 9.96 mu M. (C) 2014 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.