Parviflorals A-F, trinorcadalenes and bis-trinorcadalenes from the roots of Decaschistia parviflora

Abstract

Trinorcadalenes, parviflorals A and B (1 and 2), and four bis-trinorcadalenes, parviflorals C-F (3-6), together with the known trinorcadalenes, syriacusins A (7) and C (8), scopoletin (9) and stigmasterol were isolated from roots of Decaschistia parviflora. Their structures were established by spectroscopic techniques. The CD spectra of the bis-trinorcadalenes (3-6) established their absolute configurations at the binaphthyl axis. Further, structure 6 was confirmed by a single-crystal X-ray crystallographic analysis. Compounds 2 and 6 showed antimalarial activity against Plasmodium falciparum with IC50 values of 11.45 and 6.85 μM, respectively. Compounds 1, 5, 7 and 8 also exhibited weak antifungal activity against Candida albicans, with IC50values in the range of 37.03-197.68 μM. Compounds 1-3 and 5-8 showed weak antimycobacterial activity against Mycobacterium tuberculosis with MIC values in the range of 54.30-192.13 μM. In addition, several of these compounds possessed cytotoxicity towards the cancer cell lines, KB, MCF7 and NCI-H187 with IC50values in the range of 2.20-90.09 μM. © 2013 Elsevier Ltd. All rights reserved.