Secondary metabolites from Eupenicillium parvum and their in vitro binding affinity for human opioid and cannabinoid receptors.

Phytochemical investigation of the soil microfungus Eupenicillum parvum led to the isolation of two new compounds: a chromone derivative euparvione (1) and a new mycophenolic derivative euparvilactone (2), as well as thirteen known compounds. The structures of the new compounds were elucidated by means of extensive IR, NMR, and MS data and by comparison of data reported in the literature. The structure of the known compound 6 was confirmed by X-ray crystallography. Several isolated compounds were evaluated for in vitro binding assays using opioid receptors (subtypes δ, κ, and µ) and cannabinoid receptors (CB1 and CB2). Compound 10 displayed the best selective µ-opioid receptor and CB1 receptor binding affinities showing values of 47% and 52% at a 10 µM concentration, respectively. These findings provide insight into the potential therapeutic utility of this class of compounds.