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Myricetin antioxidant activity

Pineapple fiber showed higher (86.7%) antioxidant activity than orange peel fiber (34.6%), and myricetin was the major polyphenol identified in pineapple fiber (Larrauri and others 1997). [Pg.27]

The antioxidant activity of flavonoids in liposomes has also been extensively studied. Gordon and Roedig-Penman [93] used liposomes formed from egg PC to compare the antioxidant potencies of myricetin (31) and quercetin... [Pg.243]

In products with complex combinations of various types of flavonoids and other phenolic compounds, effort has been made to ascribe the antioxidant activity of the product to different classes of polyphenols. Frankel et al. (1995) studied 20 selected California wines and related the antioxidant activity to the polyphenolic components of the wines, rather than to resveratrol. Antioxidant activity was measured by the ability of the wines to inhibit copper-catalyzed oxidation of human LDL. The correlation coefficient between antioxidant activity and total phenolic components of the wines was r = 0.94. Individual phenolic compounds (gallic acid, catechin, myricetin, quercetin, caffeic acid, rutin, epicatechin, cyanidin, malvidin-3-glucoside) contributed to the antioxidant activity. The correlation coefficient for the compounds ranged from r = 0.92 to r = 0.38 in descending order. [Pg.113]

A catechol moiety in the B-ring is essential for a high antioxidant activity, whereas the presence of a pyrogallol moiety or a single OH group in the B-ring reduces the activity. The TEAC values were 4.72, 3.12, 2.55, and 1.34 mM for respectively quercetin, myricetin, morin, and kaempferol. [Pg.324]

According to the studies discussed above, it can be concluded that flavonoids act as antioxidants through different mechanisms. Most studies propose three structural elements as essential for optimal antioxidant activity (1) a catechol or pyrogallol moiety in the B-ring, (2) a free 3-OH group, and (3) a C2-C3 double bond. Flavanols are exceptions to the rule, since they do not possess a C2-C3 double bond. The flavonols quercetin and myricetin meet these conditions and are therefore good candidates for antioxidant use. However, similar flavonoids can act as pro-oxidants,... [Pg.333]

Antioxidant activity of flavonol derivatives kaempferol, quercetin, morin, myricetin, and rutin has been suggested to explain their anti-inflammatory, antiallergic, antiviral, as well as anticancer activities. It has been confirmed that quercetin, kaempferol, and apigenin (Fig. 4) can induce cellular antioxidant system by increasing intracellular glutathione levels [83]. [Pg.278]

Kaempferol and morin had antioxidative activity equal to myricetin, quercetin and fisetin in the presence of Cu ions, but were much less effective for Fe, V, or Cd ions (Sugihara et al. 1999). [Pg.714]

Although no good quantitative correlation between redox potentials of flavonoids and their prooxidant activities still was not documented, a relationship between the prooxidant toxicity of flavonoids to HL-60 cells and redox potentials apparently takes place [176]. However, there is a simple characteristic of possible prooxidant activity of flavonoids, which increases with an increase in reactive hydroxyl groups in the B ring. From this point of view, the prooxidant activity of flavonoids should increase in the range kaempferol < quercetin < myricetin (Figure 29.7). Thus, for many flavonoids the ratio of their antioxidant and prooxidant activities must depend on the competition between Reactions (14) and (15) and Reaction (17). [Pg.870]


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See also in sourсe #XX -- [ Pg.186 ]

See also in sourсe #XX -- [ Pg.742 ]




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