Antioxidant Properties of Quercetin
Quercetin, a plant-derived aglycone form of flavonoid glycosides, has been used as a nutritional supplement and may be beneficial against a variety of diseases, including cancer. We examined the antioxidant properties of quercetin. The reduction potential of quercetin was measured at various pH values using voltammetric methods, and its total antioxidant capacity (TAC) was measured using the phosphomolybdenum method. The effect of quercetin on production of reactive oxygen species (ROS) and nitric oxide (NO) in LPS-stimulated human THP-1 acute monocytic leukemia cells was determined by flow cytometry using CM-H2DCFDA dye. The results were compared with curcumin, a natural product exhibiting a similar range of reported health benefits. Results: 1) Quercetin has a higher reduction potential compared with curcumin at three different pH settings and is comparable to Trolox at pH 7-9.5; 2) its TAC is 3.5 fold higher than curcumin; 3) it reduced LPS-induced ROS to near normal levels; 4) it reduced LPS-induced NO production. These data provide a physico-chemical basis for comparing antioxidants, with potential benefits individually or in combination.
KeywordsDMSO Curcumin Glycoside Quercetin Auger
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- 6.Nam NH (2006) Naturally occurring NF-kappaB inhibitors. Med Chem 6:945-951Google Scholar
- 8.García-Mediavilla V, Crespo I, Collado PS, et al (2007) The anti-inflammatory flavones quercetin and kaempferol cause inhibition of inducible nitric oxide synthase, cyclooxygenase-2 and reactive C-protein, and down-regulation of the nuclear factor kappaB pathway in Chang Liver cells. Eur J Pharmacol 557(2-3):221-229PubMedCrossRefGoogle Scholar
- 12.Jovanovic SV, Steenken S, BooneCW, et al (1999) H-Atom Transfer IsAPreferred Antioxidant Mechanism of Curcumin. J Am Chem Soc 121:9677-9681Google Scholar
- 16.Sun W,WangW,Kim J, et al (2008) Anti-cancer effect of resveratrol is associatedwith induction of apoptosis via a mitochondrial pathway alignment. Adv Exp Med Biol 614:179-186Google Scholar