Gallic acid antioxidative activity

Soong YY and Barlow PJ. 2006. Quantification of gallic acid and ellagic acid from longan (Dimocarpus longan Lour.) seed and mango (Mangifera indica L.) kernel and their effects on antioxidant activity. Food Chem 87(3) 524-530. 

Classic antioxidants, vitamin E, vitamin C, and others can suppress the activation of apoptosis. For example, ascorbic acid prevented cytochrome c release and caspase activation in human leukemia cells exposed to hydrogen peroxide [128], Pretreatment with A -acctylcystcinc, ascorbate, and vitamin E decreased homocysteine thiolactone-induced apoptosis in human promyelocytic leukemia HL-60 cells [129]. Resveratrol protected rat brain mitochondria from anoxia-reoxygenation damage by the inhibition of cytochrome c release and the reduction of superoxide production [130]. However, it should be mentioned that the proapoptotic effect of ascorbate, gallic acid, or epigallocatechin gallate has been shown in the same human promyelocytic leukemia cells [131]. 

There is the often-overlooked group of polyphenols containing the derivatives of hydro-xycinnamic and hydroxybenzoic acids such as caffeic, chlorogenic, and gallic acids (Figure 29.8), which occur in food and exhibit certain antioxidant activity. For example, some caffeic acid esters isolated from propolis from honeybee hives showed antiinflammatory... 

The phenolic antioxidant activity in the corn oil emulsions of 17 selected Spanish wines and two Californian wines was examined for their preventive capability for lipid oxidation as dietary antioxidants. The inhibition of hydroperoxide formation [measured as percent of control for 10 iM gallic acid equivalents (GAE)] was increased from 8.4 to 40.2% in the presence of the red wines, from 20.9 to 45.8% with the rose wines, and from 6.5 to 47.0% with the white wines. The inhibition of hydroperoxide formation at 20 xM GAE was increased from 11.9 to 34.1% in the presence of red wines, from 0.1 to 34.5% with the rose wines, and from 3.3 to 37.2% with the white wines. The inhibition of the hexanal formation at 10 (jlM GAE was increased from 23.6 to 64.4% in the presence of red wines, from 42.7 to 68.5% with the rose wines, and from 28.4 to 68.8% with the white wines. Moreover, the inhibition of the hexanal formation at 20 xM GAE was increased from 33.0 to 46.3% in the presence of red wines, from 11.3 to 66.5% with the rose wines, and from - 16.7 to + 21.0% with the white wines. The antioxidant effect declined apparently with increasing concentration. The antioxidant activity might be ascribed to the five main groups of phenolics identified in the wines benzoic acids, anthocyanins, flavan-3-ols, flavonols, and hexanal [38]. 

Surface-active agents - and antioxidants derived from gallic acid, used as protein dispersants and food preservatives, respectively, are employed as additives. 

Phenolic acids include the benzoic acids (Ce-Ci), e.g., gallic, vanillic, syringic, protocatechuic, p-hydroxy-benzoic acid, as well as cinnamic acids (C6-C3), e.g., caffeic, p-coumaric, ferulic, sinapic acids, and their dep-sides and derivates, e.g., rosmarinic acid and lithospermic acid (Fig. 1). Phenolic acids and flavonoids in plants may occur in the free form, but they are often glycosylated with various sugars, especially glucose. Phenolic acids may also be present in the esterified as well as bound forms. Free phenolic acids are found especially in herbs and spices and, very often, in compounds responsible for antioxidant activity (benzoic and cinnamic acids and some of their derivatives). The bound forms are more common for the fruits, vegetables, and other plant materials. Therefore, in some cases, it is necessary to combine the analysis of their free and bound forms. 

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. 

Grape seeds are rich in polyphenols, especially flavanols (catechin, epicatechin) and gallic acid (Meyer et al., 1997). When grape extracts are prepared after crushing of the seeds, increased levels of phenols are obtained compared with extracts prepared with intact grape seeds. In particular, flavan-3-ol levels increased significantly. The antioxidant activity, as measured by the ability to inhibit LDL oxidation, also increased when the seeds were crushed prior to extraction. 

With respect to the activity of tannins, Momose et al. [157] have demonstrated that gallic acid exhibits higher activity than the tannins derived from it. Gallic acid was found to induce apoptosis in different cell lines this induced cell death was mediated by ROS such as hydrogen peroxide and superoxide anion, as well as by Ca2+. However, the induction of apoptosis depends on the acid s distinctive structural features rather than on its antioxidative activity [158]. In fact, the... 

These results showed that oleuropein has a good antioxidative activity. The beneficial health effects of Mediterranean diet are probably related to non-nutrient components present in foods, such as olive oil, as well as wine and others. In fact, oleuropein and hydroxy-tyrosol, both green and black tea components and gallic acid inhibit androstenedione 6-p-hydroxylase activity. 

Gallic acid (37) Antioxidant activity by inhibition of the copper-catalyzed oxidation of LDL (low density lipoprotein) 109... 

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