Harmala alkaloids are a group of psychoactive alkaloids found primarily within the seeds of Peganum harmala, also known as syrian rue. These alkaloids are of interest for their use in Amazonian shamanism, where they are derived from plants. Harmala alkaloids are naturally occurring beta-carboline alkaloids that are structurally related to harmaline, and also found in the vine Banisteriopsis caapi. They also occur in tobacco, and contribute to its subjective effects, but not to its addictiveness (which is instead caused by the presence of nicotine), and in more negligible amounts than in Peganum Harmala and Banisteriopsis cappi.
Fact-sheets from PsychonautWiki. Harm-reduction reference only — not medical advice.