Quercetin Oxidation Paradoxically Enhances its Antioxidant and Cytoprotective Properties

• DOI: 10.1021/acs.jafc.7b05214
• Publication Date: 2017-11-28T01:52:07Z
• Authors: Jocelyn Fuentes; Elías Atala; Edgar Pastene; Catalina Carrasco...; Hernán Speisky
• Keywords: 0301 basic medicine; Molecular Structure; Cell Survival; Protective Agents; Antioxidants; Quercetin oxidation metabolites; 3. Good health; 03 medical and health sciences; Cytoprotection; Tandem Mass Spectrometry; Humans; Quercetin; Antioxidant; Caco-2 Cells; Oxidation-Reduction

Quercetin oxidation is generally believed to ultimately result in the loss of its antioxidant properties. To test this assertion, quercetin was induced, and after each major metabolites identified isolated by HPLC-DAD-ESI-MS/MS, (dichlorodihydrofluorescein oxidation-inhibiting) cytoprotective (LDH leakage-preventing) properties were evaluated Hs68 Caco2 cells exposed indomethacin. Compared quercetin, whole mixture (QOX) displayed a 20-fold greater potency. After resolution QOX into 12 peaks, only one (peak 8), as 2,5,7,3',4'-pentahydroxy-3,4-flavandione or 2-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxy-3(2H)-benzofuranone tautomer, could account for effects afforded QOX. Peak 8 exerted such at 50 nM concentration, revealing potency 200-fold higher than that quercetin. The peak seen regardless whether it added 40 min before simultaneously with oxygen-reactive species-generating agent, suggesting an intracellular ability trigger early responses. Thus, present study first reveal regard actions attention should be extended toward some products.