Biomaterial Database

Protection of ascorbic acid from copper(II)-catalyzed oxidative degradation in the presence of flavonoids: quercetin, catechin and morin. 2011

Bilge Yildoğan Beker, and Inci Sönmezoğlu, and Filiz Imer, and Reşat Apak

Yildiz Technical University, Science and Arts Faculty, Chemistry Department, Esenler 34010, Istanbul, Turkey.

Protection of ascorbic acid (AA) (vitamin C) from Cu(II)-catalyzed autoxidation is an important aspect of antioxidant chemistry. The autoxidation of AA in the absence and presence of Cu(II) ions was investigated in aerated solution at room temperature and I = 0.1 ionic strength (KNO(3)); the effects of three different flavonoids of similar structure (quercetin, morin and catechin) and their mixtures on the AA system were studied. The concentration of unoxidized AA remaining in solution was measured with the modified cupric ion reducing antioxidant capacity spectrophotometric method. The Cu(II)-catalyzed oxidation at pH 4.5 followed first-order kinetics with respect to AA concentration. Catalytic autoxidation of AA was inhibited to a greater extent by stable quercetin and morin complexes of Cu(II) than by catechin complex. The inhibitive effectiveness order of mixtures gives information about possible synergistic or antagonistic combinations of flavonoid antioxidants, which should be further confirmed with other antioxidant tests.

UI	MeSH Term	Description	Entries
D010084	Oxidation-Reduction	A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).	Redox,Oxidation Reduction
D011794	Quercetin	A flavonol widely distributed in plants. It is an antioxidant, like many other phenolic heterocyclic compounds. Glycosylated forms include RUTIN and quercetrin.	3,3',4',5,7-Pentahydroxyflavone,Dikvertin
D002384	Catalysis	The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.	Catalyses
D002392	Catechin	An antioxidant flavonoid, occurring especially in woody plants as both (+)-catechin and (-)-epicatechin (cis) forms.	Catechinic Acid,Catechuic Acid,(+)-Catechin,(+)-Cyanidanol,(+)-Cyanidanol-3,(-)-Epicatechin,(2R,3R)-2-(3,4-Dihydroxyphenyl)-3,5,7-chromanetriol,2H-1-Benzopyran-3,5,7-triol, 2-(3,4-dihydroxyphenyl)-3,4-dihydro-, (2R-cis)-,3,3',4',5,7-Flavanpentol,Catergen,Cianidanol,Cyanidanol-3,Epicatechin,KB-53,Z 7300,Zyma,Cyanidanol 3,KB 53,KB53
D003300	Copper	A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55.	Copper-63,Copper 63
D005419	Flavonoids	A group of phenyl benzopyrans named for having structures like FLAVONES.	2-Phenyl-Benzopyran,2-Phenyl-Chromene,Bioflavonoid,Bioflavonoids,Flavonoid,2-Phenyl-Benzopyrans,2-Phenyl-Chromenes,2 Phenyl Benzopyran,2 Phenyl Benzopyrans,2 Phenyl Chromene,2 Phenyl Chromenes
D001205	Ascorbic Acid	A six carbon compound related to glucose. It is found naturally in citrus fruits and many vegetables. Ascorbic acid is an essential nutrient in human diets, and necessary to maintain connective tissue and bone. Its biologically active form, vitamin C, functions as a reducing agent and coenzyme in several metabolic pathways. Vitamin C is considered an antioxidant.	Vitamin C,Ascorbic Acid, Monosodium Salt,Ferrous Ascorbate,Hybrin,L-Ascorbic Acid,Magnesium Ascorbate,Magnesium Ascorbicum,Magnesium di-L-Ascorbate,Magnorbin,Sodium Ascorbate,Acid, Ascorbic,Acid, L-Ascorbic,Ascorbate, Ferrous,Ascorbate, Magnesium,Ascorbate, Sodium,L Ascorbic Acid,Magnesium di L Ascorbate,di-L-Ascorbate, Magnesium
D015394	Molecular Structure	The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.	Structure, Molecular,Molecular Structures,Structures, Molecular