flavanone

Flavanone is a class of flavonoids defined by the 2-phenylchroman-4-one skeleton, with saturation at the C2–C3 bond. The aglycone is a flavanone; common natural representatives include naringenin, eriodictyol, and hesperetin. Flavanones frequently occur in plants as glycosides, where sugar moieties are attached to hydroxyl groups (for example naringin and hesperidin).

Natural occurrence and sources

Flavanones are especially abundant in citrus fruits, where they are present as aglycones and as glycosides such as naringin and hesperidin. They also occur in several herbs and vegetables, contributing to plant defense and UV protection. The specific pattern of hydroxylation and methoxylation gives rise to a range of derivatives with distinct properties.

Biosynthesis

In plants, flavanones are produced via the phenylpropanoid pathway. Phenylalanine is converted to cinnamic acid, which is transformed into p-coumaroyl-CoA. Through the action of chalcone synthase and subsequent chalcone isomerase, a chalcone precursor is converted into a flavanone aglycone, which can be further modified by hydroxylation, methylation, or glycosylation.

Properties and applications

Flavanones are generally colorless flavonoids. They exhibit antioxidant activity and have been investigated for anti-inflammatory, antimicrobial, and cytoprotective effects. They are studied as nutraceuticals and as leads for pharmaceutical development. In plants, glycosylation affects solubility, stability, and bioavailability, as well as taste, often contributing to bitterness in citrus products.

Analytical notes

Flavanones are identified and quantified in plant extracts by HPLC and mass spectrometry, with glycosides requiring hydrolysis for some analyses to determine the aglycone composition.