Salvinorin B

Salvinorin A is the main active psychotropic molecule in Salvia divinorum, a Mexican plant which has a long history of use as an entheogen by indigenous Mazatec shamans. Salvinorin A is considered a dissociative hallucinogen. Salvinorin A is the main active psychotropic molecule in Salvia divinorum, a Mexican plant which has a long history of use as an entheogen by indigenous Mazatec shamans. Salvinorin A is considered a dissociative hallucinogen. It is structurally distinct from other naturally occurring hallucinogens (such as DMT, psilocybin, and mescaline) because it contains no nitrogen atoms; hence, it is not an alkaloid (and cannot be rendered as a salt), but rather is a terpenoid. It also differs in subjective experience, compared to other hallucinogens, and has been described as dissociative. Salvinorin A can produce psychoactive experiences in humans with a typical duration of action being several minutes to an hour or so, depending on the method of ingestion. Salvinorin A is found with several other structurally related salvinorins. Salvinorin is a trans-neoclerodane diterpenoid. It acts as a kappa opioid receptor agonist and is the first known compound acting on this receptor that is not an alkaloid. Salvinorin A was first described and named in 1982 by Alfredo Ortega and colleagues in Mexico. They used a combination of spectroscopy and x-ray crystallography to determine the chemical structure of the compound, which was shown to have a bicyclic diterpene structure. Around the same time, Leander Julián Valdés III independently isolated the molecule as part of his PhD research, published in 1983. Valdés named the chemical divinorin, and also isolated an analog that he named divinorin B. The naming was subsequently corrected to salvinorin A and B after the work was published in 1984. Valdés later isolated salvinorin C. Salvinorin A is a trans-neoclerodane diterpenoid with the chemical formula C23H28O8. Unlike other known opioid-receptor ligands, salvinorin A is not an alkaloid, as it does not contain a basic nitrogen atom. Salvinorin A has no action at the 5-HT2A serotonin receptor, the principal molecular target responsible for the actions of 'classical' psychedelics such as LSD and mescaline. Salvinorin A is active at doses as low as 200 µg. Synthetic chemicals, such as LSD (active at 20–30 µg doses), can be more potent. Research has shown that salvinorin A is a potent κ-opioid receptor (KOR) agonist (Ki = 2.4 nM, EC50 = 1.8 nM). It has a high affinity for the receptor, indicated by the low dissociation constant of 1.0 nanomolar (nM). It has been reported that the effects of salvinorin A in mice are blocked by κ-opioid receptor antagonists. In addition, salvinorin A has recently been found to act as a D2 receptor partial agonist, with an affinity of 5–10 nM, an intrinsic activity of 40–60%, and an EC50 of 48 nM. This suggests that the D2 receptor may also play an important role in its effects. Salvinorin A shows atypical properties as an agonist of the KOR relative to other KOR agonists. For instance, it is 40-fold less potent in promoting internalization (receptor downregulation) of the human KOR relative to the prototypical KOR agonist U-50488. Salvinorin A is capable of inhibiting excess intestinal motility (e.g. diarrhea), through its potent κ-opioid-activating effects. The mechanism of action for salvinorin A on ileal tissue has been described as 'prejunctional', as it was able to modify electrically induced contractions, but not those of exogenous acetylcholine. A pharmacologically important aspect of the contraction-reducing properties of ingested salvinorin A on gut tissue is that it is only pharmacologically active on inflamed and not normal tissue, thus reducing possible side-effects. Salvinorin A is soluble in organic solvents such as ethanol and acetone, but not especially so in water.