Harmine, also known as telepathine, a fluorescent harmala alkaloid belonging to the beta-carboline family of compounds. It occurs in a number of different plants, most notably the Middle Eastern plant harmal or Syrian rue and the South American vine Banisteriopsis caapi. Harmine reversibly inhibits monoamine oxidase A (MAO-A), an enzyme which breaks down monoamines, making it a RIMA. Harmine selectively binds to MAO-A but does not inhibit the variant MAO-B.