New neoclerodane diterpenoids isolated from the leaves of Salvia divinorum and their binding affinities for human κ opioid receptors Original Research Article

Bioactivity-guided fractionation of the leaves of Salvia divinorum has resulted in the isolation of three new neoclerodane diterpenoids: divinatorin D (1), divinatorin E (2), and salvinorin G (3), together with 10 known terpenoids, divinatorin C (4), hardwickiic acid (5), salvinorin-A (6), -B (7), -C (8), -D (9), -E (10), and -F (11), presqualene alcohol (12), and (E)-phytol (13). The structures of these three new compounds were characterized by spectroscopic methods. All these compounds were evaluated for their binding affinities to the human κ opioid receptors. In comparison with divinatorin D (1), divinatorin E (2), and salvinorin G (3), salvinorin A (6) is still the most potent κ agonist.