Commentary: Bioavailability of Flavonoids and Polyphenols: Call to Arms

The silkworm Green b locus encodes a quercetin 5- O -glucosyltransferase that produces green cocoons with UV-shielding properties

“…In mammals, after absorption from the small intestine, flavonoids undergo extensive metabolism, generating different conjugation forms such as glucuronides and sulfates (19,20). The bioavailability of flavonoids is generally low and can be problematic in pharmacological studies (19,21,22), as these conjugation reactions can enhance the elimination of lipophilic xenobiotics (19,21). It has been shown that glucuronidation of flavonoids can influence the bioavailability of flavonoids in mammals partly by changing their permeability and interactions with their putative transporters such as ATP-binding cassette superfamily transporters (19-21, 23, 24).…”

“…It has been shown that glucuronidation of flavonoids can influence the bioavailability of flavonoids in mammals partly by changing their permeability and interactions with their putative transporters such as ATP-binding cassette superfamily transporters (19-21, 23, 24). However, exact mechanisms for absorption, transport, and disposition of flavonoids are not well understood in any animal system (19,21), and the degree to which the site specificity in the glucuronidation step is important for the bioavailability of flavonoids remains unclear (19,21,24). It is notable that the glucosylation reaction at the 5-O position of quercetin caused a marked increase in the amount of flavonoids in silk glands, hemolymph, and cocoon (Table S1).…”

Inhibitory effects of flavonoids on TNF-α-induced IL-8 gene expression in HEK 293 cells

“…Many flavonoids have diverse biological activities that include anti-oxidant function, anti-inflammatory effects, and inhibition of cell-signaling proteins (3,5,6). These multiple biological activities have resulted in flavonoids gaining attention as potentially useful therapeutics for a variety of diseases such as cancer, cardiovascular diseases, autoimmune diseases and infectious diseases (7). However, despite the diverse beneficial biological and pharmacological effects of flavonoids, their use for the treatment of human diseases is not popular due to their high effective concentrations and poor absorptive effects and because their detailed molecular mechanisms have not yet been elucidated (7,8).…”

“…These multiple biological activities have resulted in flavonoids gaining attention as potentially useful therapeutics for a variety of diseases such as cancer, cardiovascular diseases, autoimmune diseases and infectious diseases (7). However, despite the diverse beneficial biological and pharmacological effects of flavonoids, their use for the treatment of human diseases is not popular due to their high effective concentrations and poor absorptive effects and because their detailed molecular mechanisms have not yet been elucidated (7,8). Therefore, better understanding of their activities, action mechanisms and interaction with other compounds is necessary (7,9).…”

Medicinal Potentials and Toxicity Concerns of Bioactive Principles

“…There are claims by Kim et al [154] that regular or occasional consumption of polyphenol-rich cocoa exerts beneficial effects on blood pressure, increases cerebral blood flow and possibly, for treatment of dementia. According to Hu, [155] dietary polyphenolic supplementation exert desirable outcome in complementary therapy when ingested in large quantity.…”