The object of presented study was the evaluation of antioxidant activity of extract from Zingiber officinale. A method for the preparation of the extract was chosen, which enabled to isolate mostly phenolic compounds. According to the measurements with Folin-Ciocalteu reagent, obtained extract comprised total polyphenols (181.41 mg GAE /g of extract) from which flavonoids contributed to 7.8 % (14.15 mg quercetin /g of extract). Nuclear magnetic resonance (NMR) analysis showed that the phenolic ketones were predominant in the extracts of whole phenolic compounds. According to results of two spectrophotometric methods (ABTS and DPPH test), ginger extract showed stronger ability to scavenge DPPH radical than ABTS cation radical.

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The evaluation of antioxidant potential of food has received much attention in recent years. Antioxidant compounds can scavenge free radicals and thereby can protect the human body from free radicals. This study was focused on the isolation of curcuminoids from the dried turmeric rhizome, and studying their antioxidant activity. The presence of curcuminoids was identified in turmeric sample by Nuclear Magnetic Resonance (NMR) analysis. Since neutral curcumin is known to be poorly soluble, the synthesis of curcumincyclodextrin and curcumin-phospholipid complexes was also performed. The antioxidant activity of isolated curcuminoids was assessed by two methods (ABTS and FRAP assay) and their scavenging activities were compared with those of prepared complexes. The ability to reduce ABTS radical cation decreased as follows: quercetin > trolox > curcuminoids > curcumin-cyclodextrin complex > curcumin-phospholipid complex. The reducing potential of tested samples in descending order was quercetin > trolox > curcumin-cyclodextrin complex > curcuminoids > curcumin-phospholipid complex.

Metabolic syndrome represents a clustering of risk factors related to an elevated danger of cardiovascular diseases and type 2. diabetes. The high incidence of obesity, the key risk factor in metabolic syndrome, and the lack of safe pharmaceutical agents have fuelled an increase in research related to anti-metabolic syndrome drugs. Phytochemicals have biological properties such as antioxidant, modulation of detoxifi cation enzymes, stimulation of the immune system, reduction of platelet aggregation and modulation of hormone metabolism. These compounds include vitamins, comprising of vitamin C, D and E, fl avonoids, phenolic acids, omega-3 and omega-6 fatty acids. Furthermore, the latest discoveries and studies on the molecular mechanism of these phytochemicals suggested their potential positive effect in the prevention and treatment of obesity and other risk factors associated with the metabolic syndrome. They should be incorporated in food ingredients, dietary supplements, or drug preparations. The main focus of this article is to review the available information on various aspects of phytochemicals, with special reference to their effectiveness in risk reduction of the metabolic syndrome and obesity-related diseases.

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Common buckwheat (Fagopyrum esculentum) and tartary buckwheat (Fagopyrum tataricum) cultivars originating in different world countries were investigated and compared for their quantitative and qualitative abundance of phenolics and flavonoids. Moreover, the antioxidant properties were tested using two different methods. The total phenolic and total flavonoid content ranged from 0.897 to 4.226 mg GAE g -1 dw and from 0.238 to 4.626 mg rutin g -1 dw, respectively. Flavonoids -rutin, quercetin, and hydroxybenzoic acids -gallic, protocatechuic, vanillic and syringic were identified and quantified. Rutin was the most abundant flavonoid and protocatechuic acid was the most abundant phenolic acid in evaluated cultivars. All cultivars showed significant antiradical properties, but their chelating activity was weak. The German cultivar of tartary buckwheat Lifago had significantly higher phenolic content and better antioxidant properties than other cultivars. The content of rutin was 24 times higher and free radicals scavenging activity about 70 % higher than the average value of other cultivars.