Reticuline is a

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

found in a variety of plants including ''

Lindera aggregata ''Lindera aggregata'' is a plant species belonging to the genus ''Lindera''. Other names Engl.: evergreen lindera, Japanese evergreen spicebush. TCM: trad.烏藥, simpl. 乌药 or 乌乐, pinyin : wūyào. Bot. syn.: ''Benzoin strychnifolium'' ...

'', '' Annona squamosa'', and '' Ocotea fasciculata'' (also known as ''Ocotea duckei''). It is based on the

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 wi ...

structure. Reticuline is one of the

alkaloid Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar ...

s found in

opium Opium (or poppy tears, scientific name: ''Lachryma papaveris'') is dried latex obtained from the seed capsules of the opium poppy ''Papaver somniferum''. Approximately 12 percent of opium is made up of the analgesic alkaloid morphine, which i ...

, and experiments in rodents suggest it possesses potent

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all par ...

depressing effects. It is the precursor of

morphine Morphine is a strong opiate that is found naturally in opium, a dark brown resin in poppies (''Papaver somniferum''). It is mainly used as a analgesic, pain medication, and is also commonly used recreational drug, recreationally, or to make ...

and many other alkaloids. It is also toxic to dopaminergic neurons causing a form of atypical parkinsonism known as Guadeloupean Parkinsonism.

Metabolism

3'-hydroxy-N-methyl-(S)-coclaurine 4'-O-methyltransferase In enzymology, a 3'-hydroxy-N-methyl-(S)-coclaurine 4'-O-methyltransferase () is an enzyme that catalyzes the chemical reaction :S-adenosyl-L-methionine + 3'-hydroxy-N-methyl-(S)-coclaurine \rightleftharpoons S-adenosyl-L-homocysteine + (S)-reti ...

uses ''S''-adenosyl methionine and 3'-hydroxy-''N''-methyl-(''S'')-

coclaurine Coclaurine is a nicotinic acetylcholine receptor antagonist which has been isolated from a variety of plant sources including ''Nelumbo nucifera'', '' Sarcopetalum harveyanum'', '' Ocotea duckei'', and others. It belongs to the class of tetrahydr ...

to produce ''S''-adenosylhomocysteine and (''S'')-reticuline.

Reticuline oxidase In enzymology, a reticuline oxidase () is an enzyme that catalyzes the chemical reaction :(S)-reticuline + O2 \rightleftharpoons (S)-scoulerine + H2O2 Thus, the two substrates of this enzyme are (S)-reticuline and O2, whereas its two product ...

uses (''S'')-reticuline and O₂ to produce (''S'')-

scoulerine 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, nosc ...

and H₂O₂.

Salutaridine synthase In enzymology, a salutaridine synthase () is an enzyme that catalyzes the chemical reaction :(R)-reticuline + NADPH + H+ + O2 \rightleftharpoons salutaridine + NADP+ + 2 H2O The 4 substrates of this enzyme are (R)-reticuline, NADPH, H+, an ...

uses (''R'')-reticuline, NADPH, H⁺, and O₂ to produce

salutaridine Salutaridine, also known as floripavine, is an alkaloid that is present in the morphinian alkaloid pathway of opium poppy. Its biosynthetic precursor is the alkaloid reticuline, (''R'')-reticuline. (''R'')-Reticuline is converted to salutaridine b ...

, NADP⁺, and H₂O. Salutaridine can then be transformed progressively to thebaine,

oripavine Oripavine is an opioid and the major metabolite of thebaine. It is the parent compound from which a series of semi-synthetic opioids are derived, which includes the compounds etorphine and buprenorphine. Although its analgesic potency is compar ...

, and

1,2-dehydroreticulinium reductase (NADPH) In enzymology, a 1,2-dehydroreticulinium reductase (NADPH) () is an enzyme that catalyzes the chemical reaction :(R)-reticuline + NADP \rightleftharpoons 1,2-dehydroreticulinium + NADPH + H Thus, the two substrates of this enzyme are (R)-reti ...

uses (''R'')-reticuline and NADP⁺ to produce

1,2-dehydroreticulinium Onekama ( ) is a village in Manistee County, Michigan, Manistee County in the U.S. state of Michigan. The population was 411 at the 2010 United States Census, 2010 census. The village is located on the shores of Portage Lake (Michigan), Portage Lak ...

, NADPH, and H⁺.

References

External links

{{Components of Opium Natural opium alkaloids Phenols Phenol ethers Tetrahydroisoquinolines