Antioxidant effectiveness as influenced by phenolic content of fresh orange juices

Several fresh orange juices, obtained from five different Citrus sinensis ( L.) Osbeck varieties (three pigmented varieties, Moro, Sanguinello, and Tar occo, and two blond varieties, Valencia late and Washington navel), were su bjected to antioxidant profile determination (including total polyphenols, flavanones, anthocyanins, hydroxycinnamic acids, and ascorbic acid). The an tioxidant activity of these juices was then assessed by means of different "in vitro" tests (bleaching of the stable 1,1-diphenyl-2-picrylhydrazyl rad ical; peroxidation, induced by the water-soluble radical initiator 2,2'azob is(2-amidinopropane) hydrochloride, on mixed dipalmitoylphosphatidylcholine /linoleic acid unilamellar vesicles; scavenging activity against nitric oxi de; total antioxidant status). All orange juices' tested showed an evident antioxidant effect. Our findings indicate the following: (1) the antioxidan t efficiency of orange juices may be attributed, in a significant part at l east, to their content of total phenols, (2) while ascorbic acid seems to p lay a minor role; (3) the antioxidant activity of orange juices is related not only to structural features of phytochemicals contained in them, but al so to their capability to interact with biomembranes; (4) finally, as to pi gmented juces, their antioxidant efficiency appears to be widely influenced by the anthocyanin level. One could speculate that the supply of natural a ntioxidant phenols through daily consumption of orange juice might provide additional protection against in vivo oxidation of cellular biomolecules.