Salvinorin A, the psychoactive compound in the Salvia divinorum plant, activates kappa-opioid receptors (KOP) to produce its intense hallucinogenic effects, making it the first known non-nitrogenous opioid receptor agonist. Unlike classic hallucinogens such as LSD and mescaline, its effects do not involve the 5-HT(2A) receptor. Research into its structure has yielded receptor probes and tools to study its psychological effects. Salvinorin A shows therapeutic potential for treating pain, mood disorders, substance abuse, and gastrointestinal disturbances, and suggests that nonalkaloid compounds can serve as scaffolds for developing drugs targeting aminergic G-protein coupled receptors.
New chemical methods using microwave heating enabled the first successful Diels-Alder cycloaddition reactions on the furan ring of salvinorin A, a neoclerodane diterpene natural product. This approach introduced electron-withdrawing groups and bulky aromatic rings at the C-12 position. Some of the resulting cycloadducts, specifically dimethyl- and diethylcarboxylate analogues, retained affinity and selectivity for kappa opioid receptors and acted as full agonists. However, converting these cycloadducts into planar phenyl ring systems reduced their receptor affinity. The work provides a novel strategy for rapidly exploring structure-activity relationships of furan-containing natural products.