Prunin is a flavanone glycoside found in immature citrus fruits and in tomatoes.Improved characterization of tomato polyphenols using liquid chromatography/electrospray ionization linear ion trap quadrupole Orbitrap mass spectrometry and liquid hromatography/electrospray ionization tandem mass spectrometry. Anna Vallverdu´-Queralt, Olga Jauregui, Alexander Medina-Remon, Cristina Andres-Lacueva and Rosa M. Lamuela-Raventos, Rapid Commun. Mass Spectrom., 2010, volume 24, pages 2986–2992, Its aglycone form is called naringenin.
Biosynthesis Flavonoid biosynthesis in plants uses a phenylpropanoid metabolic pathway in which the amino acid phenylalanine is converted to 4-coumaroyl-CoA. This is combined with three units of malonyl-CoA to yield a group of compounds called chalcones, which contain two phenyl rings. In the main pathway, the enzymes chalcone synthase and chalcone isomerase produce (S)-naringenin which is the immediate precursor for prunin.
Flavanone 7-O-beta-glucosyltransferase uses UDP-glucose to transfer a sugar group to one of the phenolic hydroxyl groups of (S)-naringenin.
In some citrus fruits, the product prunin is converted to naringin, a compound which is responsible for the bitter taste of grapefruit.
Flavanone 7-O-glucoside 2"-O-beta-L-rhamnosyltransferase uses UDP-rhamnose to add the second sugar component.
Metabolism in the human gut Glucosidase breaks dietary prunin back into glucose and naringenin.
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