Salvia divinorum is chemically unlike every other plant this atlas describes, and that has made it scientifically important out of proportion to its traditional role.
Its active compound, salvinorin A, is a diterpene, not an alkaloid. It contains no nitrogen, which is unusual to the point of being unique among strongly active plant psychoactives, and it acts as an agonist at the kappa opioid receptor rather than at the serotonin receptors that mescaline, psilocybin and dimethyltryptamine work through. It is also active in microgram quantities, making it one of the most potent naturally occurring psychoactive compounds known. None of that was predictable from the plant, and its discovery opened a line of pharmacological research on a receptor system that had few useful tools.
Two puzzles remain. The plant, like kava, appears to have no confirmed wild population, sets seed very poorly and is propagated by cuttings, which suggests long cultivation and raises the same question about how long the Mazatec have had it. And the traditional route matters: salvinorin A is largely inactivated in the gut, so the quid held in the mouth for absorption through the mucous membrane is not an arbitrary method but the one that works, a piece of practical knowledge arrived at without any of the chemistry.
Its legal status is inconsistent worldwide, and it was widely restricted in the 2000s after it circulated as a smoked concentrate that bears little relation to the Mazatec practice.