Isolation and bioassay studies of Cryptoporic acids from Cryptoporus volvatus fruiting bodies

Abstract

Bioassay directed studies on the chemical constituents of Cryptoporus volvatus, have yielded fourteen cryptoporic acids (CPAs) from the fruiting bodies. The structures of the isolated compounds were elucidated by extensive spectroscopic analysis (1D- and 2D-NMR, HR-ESI-Q-TOF-MS, etc.). In this paper we report CPA-D methylester (9, CPA-P) as a new compound. CPA-A methylester (2), CPA-D dimethylester (10), and CPA-E dimethylester (13) were isolated as natural compounds for the first time, along with five known compounds; CPA-A (1), CPA-B (4), CPA-B methylester (5), CPA-D (8) and CPA-H (15). Additionally six new ethylesters, CPA-A ethylester (3), CPA-B ethylester (6), acetyl CPA-B ethylester (7), CPA-D ethylester (11), CPA-D diethylester (12), acetyl CPA-E diethylester (14) are also being reported as probable artefacts which could have been formed during the extraction procedure. The allelopathic potential of these compounds was also studied against lettuce seedlings, only CPA-H (15) exhibited strong growth inhibitory activity to radicles and hypocotyls at IC_<50>=0.62mM, and 0.83mM, respectively, further, 1 showed second activity IC_<50>=1.6mM, and 0.24mM, respectively. The cytotoxic activities of the several cryptoporic acids was also evaluated in preliminary cell proliferation assay (WST-1 assay) to HeLa cell, only 9 showed strong and 8 moderate activity at 25μM.