Incubation of four common cannabinoids with vegetative cultures of the fungus Syricrphalasfrum racernosurn yielded a number of polar metabolites. Major metabolites of A9-tetrahydrocannabinol, A8-tetrahydrocannabinol, cannabidiol and cannabinol were eluted from preparative thin-layer chromatographic plates and analyzed by gas-liquid chromatography mass spectrometry. The mass spectrum of each of the compounds examined showed a molecular ion corresponding to a monohydroxylated derivative of the parent cannabinoid. Identification of the major metabolite of each cannabinoid as the product of hydroxylation in the penultimate (4') position of the n-pentyl sidechain was made by analysis of the mass spectra of underivatized and TMS derivatized metabolites and by comparison with model compounds. A number of prominent fragment ions in the mass spectra were identified as arising through known fragmentation pathways of cannabinoids.

Partially purified glucuronyltransferase immobilized on beaded sepharose has been used to synthesize the glucuronide conjugates of cannabinol, cannabidol, delta9-tetrahydrocannabinol and delta8-tetrahydrocannabinol. Trimethylsilylated methyl esters and per(trimethylsilyl) derivatives of these conjugates have been characterized by their gas chromatographic retention times and their electron impact and ammonia chemical ionization mass spectra.