Oxidation products of hyperforin from Hypericum perforatum

Abstract

The isolation of two oxidation products of hyperforin from the aerial parts of Hypericum perforatum and their structure determination by means of 2D NMR methods is reported. The products had the same 1-(2-methyl-1- oxopropyl)-2,12-dioxo-3,10β-bis(3-methyl-2-butenyl)-11β-methyl-11α-(4- methyl-3-pentenyl)-5-oxatricyclo[6.3.1.0 4,8 ]-3-dodecene skeleton. In addition, one of them, with the same number of carbons as hyperforin (C 35 H 52 O 5 ), contained a 1-methyl-1-hydroxyethyl group in the 6β- position, whereas the other compound (a hemiacetal, C 32 H 46 O 5 ), presumably a degradation product of hyperforin, exhibited a 6-hydroxy function. The latter was an inseparable mixture of 6α- and 6β-hydroxy epimers undergoing (according to phase sensitive NOESY) mutual interconversion.