Bioavailability of flavonoids: a review of their membrane transport and the function of bilitranslocase in animal and plant organisms.
Fruits and vegetables are rich in flavonoids, and ample epidemiological data show that diets rich in fruits and vegetables confer protection against cardiovascular, neurodegenerative and inflammatory diseases, and cancer. However, flavonoid bioavailability is reportedly very low in mammals and the molecular mechanisms of their action are still poorly known. This review focuses on membrane transport of flavonoids, a critical determinant of their bioavailability. Cellular influx and efflux transporters are reviewed for their involvement in the absorption of flavonoids from the gastro-intestinal tract and their subsequent tissue distribution. A focus on the mammalian bilirubin transporter bilitranslocase (TCDB 2.A.65.1.1) provides further insight into flavonoid bioavailability and its relationship with plasma bilirubin (an endogenous antioxidant). The general function of bilitranslocase as a flavonoid membrane transporter is further demonstrated by the occurrence of a plant homologue in organs (petals, berries) where flavonoid biosynthesis is most active. Bilitranslocase appears associated with sub-cellular membrane compartments and operates as a flavonoid membrane transporter.
Passamonti
Sabina
S
University of Trieste, Department of Life Sciences, via L. Giorgieri 1, 34127 Trieste, Italy. spassamonti@units.it
Terdoslavich
Michela
M
Franca
Raffaella
R
Vanzo
Andreja
A
Tramer
Federica
F
Braidot
Enrico
E
Petrussa
Elisa
E
Vianello
Angelo
A
D000818:Animals; D001682:Biological Availability; D053898:Biosynthetic Pathways; D002570:Ceruloplasmin; D005419:Flavonoids / Q000096:biosynthesis / Q000145:classification / Q000493:pharmacokinetics*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D026901:Membrane Transport Proteins / Q000502:physiology*; D008954:Models, Biological; D015394:Molecular Structure; D010944:Plants / Q000378:metabolism*
D005419:Flavonoids; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D002570:Ceruloplasmin; C033838:bilitranslocase