Scoulerine, also known as discretamine and aequaline, is a

benzylisoquinoline Substitution of the heterocycle isoquinoline at the C1 position by a benzyl group provides 1‑benzylisoquinoline, the most widely examined of the numerous benzylisoquinoline structural isomers. The 1-benzylisoquinoline moiety can be identified w ...

alkaloid Alkaloids are a broad class of natural product, naturally occurring organic compounds that contain at least one nitrogen atom. Some synthetic compounds of similar structure may also be termed alkaloids. Alkaloids are produced by a large varie ...

(BIA) that is derived directly from (''S'')-

reticuline Reticuline is an alkaloid found in opium and a variety of plants including ''Lindera aggregata'', ''Annona squamosa'', and ''Ocotea#Selected species, Ocotea fasciculata'' (also known as ''Ocotea duckei''). Experiments in rodents suggest reticuli ...

through the action of berberine bridge enzyme. It is a precursor of other BIAs, notably

berberine Berberine is a Quaternary ammonium cation, quaternary ammonium salt from the protoberberine group of benzylisoquinoline alkaloids, occurring naturally as a secondary metabolite in some plants including species of ''Berberis'', from which its name ...

noscapine Noscapine, also known as narcotine, nectodon, nospen, anarcotine and (archaic) opiane, is a benzylisoquinoline alkaloid of the phthalideisoquinoline structural subgroup, which has been isolated from numerous species of the family Papaveraceae (p ...

, (''S'')-

tetrahydropalmatine Tetrahydropalmatine (THP) is an isoquinoline alkaloid found in several different plant species, mainly in the genus ''Corydalis'' ( Yan Hu Suo), but also in other plants such as '' Stephania rotunda''. These plants have traditional uses in Chin ...

, and (''S'')-stylopine, as well as the alkaloids

protopine Protopine is an alkaloid occurring in opium poppy, ''Corydalis'' tubers and other plants of the family papaveraceae, like ''Fumaria officinalis''. Protopine is metabolically derived from the Benzylisoquinoline alkaloids, benzylisoquinoline alkaloi ...

, and

sanguinarine Sanguinarine is a polycyclic quaternary alkaloid. It is extracted from some plants, including the bloodroot plant, from whose scientific name, ''Sanguinaria canadensis,'' its name is derived; the Mexican prickly poppy (''Argemone mexicana''); ''C ...

. It is found in many plants, including

opium poppy ''Papaver somniferum'', commonly known as the opium poppy or breadseed poppy, is a species of flowering plant in the family Papaveraceae. It is the species of plant from which both opium and poppy seeds are derived and is also a valuable orname ...

, '' Croton flavens'', and certain plants in the genus ''

Erythrina ''Erythrina'' is a genus of plants in the pea family, Fabaceae. It contains about 130 species, which are distributed in tropical and subtropical regions worldwide. They are trees, with the larger species growing up to in height. These species ...

''. Studies show that scoulerine is an

antagonist An antagonist is a character in a story who is presented as the main enemy or rival of the protagonist and is often depicted as a villain.in vitro ''In vitro'' (meaning ''in glass'', or ''in the glass'') Research, studies are performed with Cell (biology), cells or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in ...

'' at the α₂-

adrenoceptor The adrenergic receptors or adrenoceptors are a class of G protein-coupled receptors that are targets of many catecholamines like norepinephrine (noradrenaline) and epinephrine (adrenaline) produced by the body, but also many medications like bet ...

, α_1D-

and

5-HT receptor 5-HT receptors, 5-hydroxytryptamine receptors, or serotonin receptors, are a group of G protein-coupled receptor and ligand-gated ion channels found in multiple tissues including the Central nervous system, central and peripheral nervous systems ...

. It has also been found to be a GABA_A receptor agonist ''in vitro''.

References

{{reflist Isoquinolinoisoquinolines Natural opium alkaloids Hydroxyarenes Catechol ethers Methoxy compounds