Abstract
Four undescribed cucurbitacins, designated as petiolaticins A-D, and four known cucurbitacins were isolated from the bark and leaves of Elaeocarpus petiolatus (Jack) Wall. Their chemical structures were elucidated based on detailed analyses of the NMR and MS data. The absolute configuration of petiolaticin A was also determined by X-ray diffraction analysis. Petiolaticin A represents a cucurbitacin derivative incorporating a 3,4-epoxyfuranylbearing side chain, while petiolaticin B possesses a furopyranyl unit fused to the tetracyclic cucurbitane core structure. Petiolaticins A, B, and D were evaluated in vitro against a panel of human breast, pancreatic, and colorectal cancer cell lines. Petiolaticin A exhibited the greatest cytotoxicity against the MDA-MB-468, MDA-MB-231, MCF-7, and SW48 cell lines (IC50 7.4, 9.2, 9.3, and 4.6 mu M, respectively). Additionally, petiolaticin D, 16 alpha,23 alpha-epoxy-3 beta,20 beta-dihydroxy-10 alpha H,23 beta H-cucurbit-5,24-dien-11-one, and 16 alpha,23 alpha-epoxy-3 beta,20 beta-dihydroxy-10 alpha H,23 beta H-cucurbit-5,24-dien-11-one 3-O-beta-D-glucopyranoside were tested for their ability to inhibit cell entry of a pseudotyped virus bearing the hemagglutinin envelope protein of a highly pathogenic avian influenza virus. Petiolaticin D showed the highest inhibition (44.3%), followed by 16 alpha,23 alpha-epoxy-3 beta,20 beta-dihydroxy-10 alpha H,23 beta H-cucurbit-5,24-dien-11-one (21.0%), and 16 alpha,23 alpha-epoxy-3 beta,20 beta-dihydroxy-10 alpha H,23 beta H-cucurbit-5,24-dien-11-one 3-O-beta-D-glucopyranoside showed limited inhibition (9.0%). These preliminary biological assays have demonstrated that petiolaticins A and D possess anticancer and antiviral properties, respectively, which warrant for further investigations.
NSTL
Elsevier