Scoulerine, also known as discretamine and aequaline, is a benzylisoquinoline alkaloid (BIA) that is derived directly from (S)-reticuline through the action of berberine bridge enzyme.

It is a precursor of other BIAs, notably berberine, noscapine, (S)-tetrahydropalmatine, and (S)-stylopine, as well as the alkaloids protopine, and sanguinarine.

[1] It is found in many plants, including opium poppy,[2] Croton flavens,[3] and certain plants in the genus Erythrina.

[4] Studies show that scoulerine is an antagonist in vitro at the α2-adrenoceptor, α1D-adrenoceptor and 5-HT receptor.

[5][6] It has also been found to be a GABAA receptor agonist in vitro.