Flavonoid Contents and Antioxidant Activity in Fruit,Vegetables and Other Types of Food

Flavonoids are a class of natural polyphenolic compounds which cannot be synthesized by humans. These substances possess a series of biological properties, acting on biological systems as antioxidants. The purpose of this study was to analyze the properties of certain foods, determining the total flavonoids as well as their antioxidant activity and fat concentration. We evaluated several foods purchased at the local market, with respect to its antioxidant activity, using two experimental models, the discoloration of DPPH˙ radical and ABTS-. Some foods such as pitanga showed antioxidant activity. The lipid content of fatty foods like aaí, cacao and cupuaú was determined. Other foods, including pitanga, aaí, cacao and cupuaú, were evaluated for flavonoid content and antioxidant activity using multivariate statistical analysis (PCA) as a statistical tool to evaluate the correlation between these two parameters. As samples with ED50 up to 500 μg/mL show promising antioxidant activity, several Brazilian fruit and vegetables could be consumed to this end, with a good correlation between flavonoid content and antioxidant activity in most samples. The daily dose of different types of food for antioxidant activity has been calculated based on these results.

Metabolic responses of Eucalyptus species to different temperature regimes

Species and hybrids of Eucalyptus are the world＇s most widely planted hardwood trees. They are cultivated across a wide range of latitudes and therefore environmen- tal conditions. In this context, comprehensive metabolo- mics approaches have been used to assess how different temperature regimes may affect the metabolism of three species of Eucalyptus, E. dunnii, E. grandis and E. pellita. Young plants were grown for 53 d in the greenhouse and then transferred to growth chambers at 10℃, 20℃ or 30℃ for another 7 d. In all three species the leaf chlorophyll content was positively correlated to temperature, and in E. pellita the highest temperature also resulted in a significant increase in stem biomass. Comprehensive metabolomics was performed using untargeted gas chromatography mass spectrometry （GC-MS） and liquid chromatography （LC）-MS. This approach enabled the comparison of the relative abundance of 88 polar primary metabolites from GC-MS and 625 semi-polar secondary metabolites from LC-MS. Using principal components analysis, a major effect of tempera- ture was observed in each species which was larger than that resulting from the genetic background. Compounds mostly affected by temperature treatment were subsequently selected using partial least squares discriminant analysis and were further identified. These putative annotations indicated that soluble sugars and several polyphenols, including tannins, triterpenes and alkaloids were mostly influenced.

Biquinho pepper(Capsium chinense):Bioactive compounds,in vivo and in vitro antioxidant capacities and anti-cholesterol oxidation kinetics in fish balls during frozen storage

The present study reports bioactive constituents from biquinho pepper,such as carotenoids,capsaicinoids,and capsinoids,identified by UHPLC-MS.Biquinho pepper extract showed an antioxidant potential by DPPH(33.17±0.08%),ORAC(32.35±0.02μM TE/g),β-carotene/linoleic acid(55.80±1.30%),and FRAP(315.88±4.23μmol TE/g)assays.Additionally,in vivo antioxidant analyses demonstrated that the pepper extract(170μg/mL)decreased the damage promoted by H_(2)O_(2) in Saccharomyces cerevisiae cells.Fish balls were prepared using different concentrations of pepper(0.0%,0.5%,0.75%,1.0%)to investigate its antioxidant effect during frozen storage.Biquinho pepper effectively reduced the formation of cholesterol oxides and preserved essential fatty acids,mainly in samples containing 1.0%of pepper.Moreover,this treatment was more efficient than sodium erythorbate(p<0.05),which was used as standard.The kinetics of cholesterol oxidation was also determined,showing that both cholesterol degradation and cholesterol oxides formation fit a first-order kinetic model(R^(2)>0.8).