Reticuline is a tetrahydroisoquinoline alkaloid. It is also classified as a benzylisoquinoline alkaloid.

Reticuline is found in opium and a variety of plants including Lindera aggregata, Annona squamosa, and Ocotea fasciculata (also known as Ocotea duckei).

In rodents reticuline possesses potent central nervous system depressing effects. It is the precursor of morphine and many other alkaloids. It is also toxic to dopaminergic neurons causing a form of atypical parkinsonism known as Guadeloupean Parkinsonism.

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 uses (S)-reticuline and O₂ to produce (S)-scoulerine and H₂O₂.

Salutaridine synthase uses (R)-reticuline, NADPH, H⁺, and O₂ to produce salutaridine, NADP⁺, and H₂O. Salutaridine can then be transformed progressively to thebaine, oripavine, and morphine.

1,2-dehydroreticulinium reductase (NADPH) uses (R)-reticuline and NADP⁺ to produce 1,2-dehydroreticulinium, NADPH, and H⁺.

The dictionary definition of reticuline at Wiktionary