The sesquiterpenoid contents of fruit bodies of Russula delica

The sesquiterpenoids extracted from both intact injured fruit bodies of Russula delica (Russulaceae) with EtOAc and dichloromethane have been investigated. The dichloromethane extract of intact specimens contained stearoyldelicone (2b) (75%) and stearoylplorantinone B (3b) (25%), while the EtOAc extracts contained comparable amounts of 3b, no 2b but instead the illudalane 9e. The latter is believed to be an artifact due to the reaction between 2b and acetic acid, produced by hydrolysis of the solvent by esterases present in the fruit bodies. EtOAc has, with good results, routinely been employed as an extraction solvent for fruit bodies of species belonging to Russulaceae, but is obviously degradable by some species and should be used with caution. In injured fruit bodies of R delica, the stearic acid esters are converted into a series of free sesquiterpenes, and the isolation of four new compounds [plorantinone D (4b), epiplorantinone B (5a), deliquinone (7) and 2,9-epoxydeliquinone (8)], obtained from both EtOAc and dichloromethane extracts of injured specimens, is described.