Compound Monograph
Harmalol
Harmalol is a beta-carboline alkaloid related to harmaline, occurring in Syrian rue and related plants.
Classification
Harmalol is a beta-carboline alkaloid, part of the alkaloids class. Nitrogen-containing, often bitter and physiologically potent compounds — the group behind many of the strongest plant medicines and poisons.
Where Does It Come From? (2)
Harmalol is a naturally occurring beta-carboline alkaloid, found in Syrian rue and Passionflower. It is flagged as moderately toxic.
Research & Evidence
Harmalol is a beta-carboline (harmala) alkaloid closely related to harmaline, differing in that it carries a hydroxyl group in place of harmaline’s methoxy group. It occurs in Syrian rue and related plants and, like other harmala alkaloids, shows monoamine oxidase inhibiting activity in laboratory studies. It is generally a minor constituent and has been studied much less than harmine and harmaline.
Monoamine oxidase (MAO) inhibition
Like the other harmala alkaloids, harmalol inhibits monoamine oxidase — reported as MAO-A-preferring, consistent with its β-carboline relatives — but it is a minor constituent that has been studied far less than harmine and harmaline, and no reliable isolated-compound potency value is established for it. See the natural MAO inhibitors guide for the better-characterised β-carbolines.
Toxicity & Safety
As a monoamine oxidase inhibiting beta-carboline, harmalol shares the general interaction cautions of this group, particularly with serotonergic drugs. Its safety profile in isolation is not well characterised.