Flavones with in vitro radioligand binding affinity for human opioid recepetors isolated from Perovskia atriplicifolia

Abstract

Russian sage (Perovskia atriplicifolia) grows over the rocky areas of Central Asia including Pakistan, Afghanistan, Iran, and Tibet. It is mainly known for its ornamental, flavoring qualities along with its use in chronic dysentery as a decoction and is also smoked as a euphoriant. Bioassay-guided fractionation of the EtOAc extract from the leaves of P. atriplicifolia resulted in the isolation of four flavones 1 – 4. Compound 1, 3, 4 showed high displacement of radioligand binding affinity, selective for δ opioid receptor with IC50 values ranging from 6.1 to 49.5 µM. Docking studies might explain the predicted orientation of the ligand in the active site of the receptor. These studies have important implications in our understanding the features of these non-nitrogenous δ opioid receptor ligands.