Investigation of in Vitro Opioid Receptor Binding Activities of Some Turkish Salvia Species

Abstract

Kappa Opioid Peptide Receptor (KOPr) activation produces analgesic, psychotomimetic, diuretic and antipruritic effects. KOPr ligands are investigated for their potential roles in the treatment of addiction, depression, feeding behavior, psychosis and schizophrenia. In this study the methanolic extracts of a number of Salvia species which are native to Turkey (S. tomentosa, S. tchihatcheffii, S. rosifolia, S. dichroantha and S. sclarea) were tested for their potential binding to opioid receptors in rat brain membranes and Chinese Hamster Ovary Cells expressing human KOPr (CHO-KOPh). [(3)H] Diprenorphine, an unselective opioid antagonist, was utilized in the radioligand receptor binding assays. All extracts (0.11 mg/mL) inhibited the [(3)H] Diprenorphine binding with ranging KOPr binding affinities. More than 50% inhibition of diprenorphine binding was shown only with Salvia dichroantha and Salvia sclarea both in rat brain membranes and CHO-KOPh membranes. Among them Salvia sclarea deserves further investigation for its active component(s) and its pharmacological characterization. This study clearly demonstrates the potential opioid receptor binding activities of several Turkish Salvia species. This work constitutes the first study on in vitro opioid receptor binding activities of Salvia species from the Turkish flora.