Antioxidants are substances that prevent oxidation of other compounds or neutralize free radicals. Spices and herbs are rich sources of antioxidants. They have been used in food and beverages to enhance flavor, aroma and color. Due to their excellent antioxidant activity, spices and herbs have also been used to treat some diseases. In this review article, the chemical composition and antioxidant activity of spices and culinary herbs are presented. The content of flavonoids and total polyphenols in different spices and herbs are summarized. The applications of spices and their impacts on human health are briefly described. The extraction and analytical methods for determination of antioxidant capacity are concisely reviewed.

No abstract

A comprehensive nonenzymatic oxidation mechanism in betanin plant pigment as well as its derivatives, 2-decarboxybetanin, 17-decarboxybetanin, 2,17-bidecarboxybetanin, and neobetanin, in the presence of ABTS cation radicals was investigated by LC-DAD-ESI-MS/MS. The main compounds formed during the first step of betanin and 2-decarboxybetanin oxidation are 2-decarboxy-2,3-dehydrobetanin and 2-decarboxyneobetanin, respectively. In contrast to betanin, the reaction mechanism for 2-decarboxybetanin includes more oxidation pathways. Parallel transformation of 2-decarboxybetanin quinone methide produces neoderivatives according to an alternative reaction that omits the presumably more stabile intermediate 2-decarboxy-2,3-dehydrobetanin. The main oxidation product after the first reaction step for both 17-decarboxybetanin and 2,17-bidecarboxybetanin is 2,17-decarboxy-2,3-dehydrobetanin. This product is formed through irreversible decarboxylation of the 17-decarboxybetanin quinone methide or by oxidation of 2,17-bidecarboxybetanin. Oxidation of neobetanin results primarily in a formation of 2-decarboxy-2,3-dehydroneobetanin by a decarboxylative transformation of the formed neobetanin quinone methide. The elucidated reaction scheme will be useful in interpretation of redox activities of betalains in biological tissues and food preparations.

This review summarizes published information concerning the determination of antioxidant activity (AA) in coffee samples by various methods (ORAC, FRAP, TRAP, TEAC, etc.) in vitro and limited data of antiradical activity of coffee products in vitro and in vivo. Comparison is carried out of the AA of coffee Arabica and coffee Robusta roasted at different temperatures as well as by different roasting methods (microwave, convection, etc.). Data on the antiradical activity of coffee is provided. The antioxidant activity of coffee, tea, cocoa, and red wine is compared. At the end of this review, the total antioxidant content (TAC) of coffee samples from 21 coffee-producing countries as measured by an amperometric method is provided. The TAC of green and roasted coffee beans is also compared.

No abstract

The antioxidative mechanism of action of betalains is of significant interest because these pigments are recently emerging as highly bio-active natural compounds with potential benefits to human health. Betanidin, the basic betacyanin, comprises the 5,6-dihydroxyl moiety, which results in its high antioxidant activity. Oxidation of betanidin by voltammetric techniques and chro matographic identification of the oxidation products with spectrophotometric and mass spectrometric detection (LC-DAD-MS/MS) were performed. Two main oxidation peaks for betanidin are observable at pH 3-5. These peaks become merged at higher pH, suggesting a different mechanism of oxidation at higher and lower pH values. The low oxidation potential of betanidin confirms its very strong reduction properties. The presence of two prominent oxidized products, 2-decarboxy-2,3-dehydrobetanidin and 2,17-bidecarboxy-2,3-dehydrobetanidin, indicates their generation through two reaction routes with two different quinonoid intermediates: dopachrome derivative and quinone methide. Both lead to the decarboxylative dehydrogenation of betanidin. Subsequent oxidation and rearrangement of the conjugated chromophoric system results in formation of 14,15-dehydrogenated derivatives.

Commercial whole coffee fruit extracts and powder samples were analyzed for chlorogenic acids (CGA), caffeine and antioxidant activities. CGA and caffeine were characterized by LC-MS(n) and HPLC accordingly, and quantified by UV absorbance. ORAC, HORAC, NORAC, SORAC and SOAC (antioxidant capacities) were assessed. Three caffeoylquinic acids, three feruloylquinic acids, three dicaffeoylquinic acids, one p-coumaroylquinic acid, two caffeoylferuloylquinic acids and three putative chlorogenic lactones were quantified, along with a methyl ester of 5-caffeoylquinic acid (detected in one sample, the first such report in any coffee material). Multistep whole coffee fruit extracts displayed higher CGA content than single-step extracts, freeze-dried, or air-dried whole raw fruits. Caffeine in multistep extracts was lower than in the single-step extracts and powders. Antioxidant activity in whole coffee fruit extracts was up to 25-fold higher than in powders dependent upon the radical. Total antioxidant activity of samples displayed strong correlation to CGA content.

1Air dried whole coffee fruits, beans and husks from China, India and Mexico were analysed 2 for their chlorogenic acids (CGA), caffeine, and polyphenolic content. Analysis was by 3 HPLC and Orbitrap exact mass spectrometry. Total phenol, total flavonol and antioxidant 4 capacity were measured. 5The hydroxycinnamate profile consisted of caffeoylquinic acids, feruloyquinic acids, 6 dicaffeoylquinic acids and caffeoyl-feruloylquinic acids. A range of flavan-3-ols as well as 7 flavonol conjugates were detected. The CGA content was similar for both Mexico and India 8 coffee fruits but was much lower in China samples. Highest levels of flavan-3-ols were 9 found in the Indian samples whereas Mexico samples contained the highest flavonols. 10Amounts of CGAs in the beans were similar to those in the whole fruits, but flavan-3-ols and 11 flavonols were not detected. The husks contained the same range of polyphenols as in the 12 whole fruits. Highest levels of caffeine were found in the Robusta samples. 13 14