2-2--azino-di-(3-ethylbenzothiazoline)-6-sulfonic-acid and morin

In the present study, non-thermal dielectric barrier discharge (DBD) plasma of induced structural changes of morin resulted in the isolation of one previously undescribed benzofuranone derivative, along with two known compounds. The chemical structures of these degradation products were elucidated by UV, NMR and FAB-MS spectroscopic analyses. The isolated three compounds showed potent antioxidative activities in two different tests, with IC

Topics: Antioxidants; Benzofurans; Benzothiazoles; Biodegradation, Environmental; Electric Impedance; Flavonoids; Humans; Lipase; Molecular Structure; Pancreas; Sulfonic Acids

Polyphenolic compounds usually showed different antioxidant capacities depending on the assay methods used. To determine the possible chemical cause for this assay-dependence, two flavonols, kaempferol and morin, were selected as the model molecules for the comparative investigation between electrochemical and chemical oxidations. The electro-oxidation of the flavonols was studied using cyclic voltammetry and in situ UV-Vis spectroelectrochemical technique with a long-optical-path thin-layer electrolytic cell. The spectral changes recorded in different potentials were compared with those in the chemical oxidation by H(2)O(2) or ABTS(*+) radical in the same thin-layer cell. The 4'-OH group of either sample was first oxidized at lower potentials or induced by H(2)O(2), and in this case kaempferol was somewhat more active than morin. With an additional 2'-OH group, morin underwent the secondary oxidation in moderately higher potentials or by ABTS(*+), showing antioxidant capacity about twice of that of kaempferol. This study clarified that the chemical oxidation of a polyphenolic compound by the oxidants with different reactivities, which corresponded to its electro-oxidation in different anodic peaks, had a difference in number of oxidizable OH-groups, leading to the difference in antioxidant capacity.

Topics: Antioxidants; Benzothiazoles; Electrochemistry; Flavonoids; Hydrogen Peroxide; Kaempferols; Oxidation-Reduction; Spectrophotometry; Sulfonic Acids