Harmine (telepathine) is a naturally occuring beta-carboline and fluorescent harmala alkaloid found in a number of different plants, most notably the Middle Eastern plant harmal or Syrian rue (Peganum harmala) and the South American vine Banisteriopsis caapi (formerly known as 'yage' or 'ayahuasca'). Harmine is a RIMA because it reversibly inhibits the enzyme monoamine oxidase A (MAO-A), which breaks down monoamines. While it does not inhibit the MAO-B variant, harmine binds to MAO-A specifically. In addition, it is an inhibitor of tyrosine phosphorylation-regulated kinase (DYRK) with anti-inflammatory and anti-cancer properties. With a Ki of 397 nM, harmine exhibits a high affinity for the 5-HT2A serotonin receptor.