beta-Carboline alkaloids in Peganum harmala and inhibition of human monoamine oxidase (MAO).
T Herraiz, D González, C Ancín-Azpilicueta, V J Arán, H Guillén
Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association March 1, 2010 DOI: 10.1016/j.fct.2009.12.019 via PubMed
Summary
AI-generated from the abstractPeganum harmala (Syrian rue) seeds and roots contain high levels of beta-carboline alkaloids—harmine, harmaline, harmalol, harmol, and tetrahydroharmine—that strongly and selectively inhibit human monoamine oxidase A (MAO-A), with seed extracts having an IC50 of 27 µg/L and root extracts an IC50 of 159 µg/L. Stems, leaves, and flowers have little to no alkaloids and are poor MAO inhibitors. The potent MAO-A inhibition by seed and root extracts likely contributes to the plant's psychoactive and toxic effects and may underlie its traditional use as an antidepressant.
Study at a glance
| Characteristics | Laboratory study Peer reviewed |
|---|---|
| Population | Peganum harmala plant extracts |
| Key finding | Seed and root extracts of Peganum harmala are potent, reversible, competitive inhibitors of human MAO-A, with seed extracts (IC50 27 µg/L) more potent than root extracts (IC50 159 µg/L), while stem and leaf extracts are poor inhibitors. |
Abstract
Peganum harmala L. is a multipurpose medicinal plant increasingly used for psychoactive recreational purposes (Ayahuasca analog). Harmaline, harmine, harmalol, harmol and tetrahydroharmine were identified and quantified as the main beta-carboline alkaloids in P. harmala extracts. Seeds and roots contained the highest levels of alkaloids with low levels in stems and leaves, and absence in flowers. Harmine and harmaline accumulated in dry seeds at 4.3% and 5.6% (w/w), respectively, harmalol at 0.6%, and tetrahydroharmine at 0.1% (w/w). Roots contained harmine and harmol with 2.0% and 1.4% (w/w), respectively. Seed extracts were potent reversible and competitive inhibitors of human monoamine oxidase (MAO-A) with an IC(50) of 27 microg/l whereas root extracts strongly inhibited MAO-A with an IC(50) of 159 microg/l. In contrast, they were poor inhibitors of MAO-B. Inhibition of MAO-A by seed extracts was quantitatively attributed to harmaline and harmine whereas inhibition by root extracts came from harmine with no additional interferences. Stems and leaves extracts were poor inhibitors of MAO. The potent inhibition of MAO-A by seed and root extracts of P. harmala containing beta-carbolines should contribute to the psychopharmacological and toxicological effects of this plant and could be the basis for its purported antidepressant actions.