Reticuline is an

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 ...

found in

opium Opium (also known as poppy tears, or Lachryma papaveris) is the dried latex obtained from the seed Capsule (fruit), capsules of the opium poppy ''Papaver somniferum''. Approximately 12 percent of opium is made up of the analgesic alkaloid mor ...

and 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 ''Annona squamosa'' is a small, well-branched tree or shrub from the family Annonaceae that bears edible fruits called sugar apples or sweetsops or custard apples. It tolerates a tropical lowland climate better than its relatives ''Annona reticul ...

'', and '' Ocotea fasciculata'' (also known as ''Ocotea duckei''). Experiments in rodents suggest reticuline possesses potent

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

depressing effects. It is the precursor of

morphine Morphine, formerly also called morphia, is an opiate that is found naturally in opium, a dark brown resin produced by drying the latex of opium poppies (''Papaver somniferum''). It is mainly used as an analgesic (pain medication). There are ...

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 uses ''S''-adenosyl methionine and 3'-hydroxy-''N''-methyl-(''S'')- coclaurine to produce ''S''-adenosylhomocysteine and (''S'')-reticuline.

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

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, nosca ...

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+, and ...

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

salutaridine Salutaridine, also known as floripavine, is an 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 ...

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

thebaine Thebaine (paramorphine), also known as codeine methyl enol ether, is an opiate alkaloid, its name coming from the Greek Θῆβαι, '' Thēbai'' (Thebes), an ancient city in Upper Egypt. A minor constituent of opium, thebaine is chemically simi ...

oripavine Oripavine is an opioid and the major metabolite of thebaine. It is the precursor to the semi-synthetic compounds etorphine and buprenorphine. Although this chemical compound has analgesic potency comparable to morphine, it is not used clinica ...

, 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)-retic ...

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

1,2-dehydroreticulinium Onekama ( ) is a village in Manistee County in the U.S. state of Michigan. The population was 399 at the 2020 census. The village is located on the northeast shore of Portage Lake and is surrounded by Onekama Township. The town's name is deriv ...

, NADPH, and H⁺.

References

External links

{{Components of Opium Hydroxyarenes Natural opium alkaloids Phenols Phenol ethers Tetrahydroisoquinoline alkaloids