A growing market for novel antioxidants obtained from non-expensive sources justifies educated screening of microalgae for their potential antioxidant features. Characterization of the antioxidant profile of 18 species of cyanobacteria (prokaryotic microalgae) and 23 species of (eukaryotic) microalgae is accordingly reported in this paper. The total antioxidant capacity, accounted for by both water- and lipid-soluble antioxidants, was evaluated by the (radical cation) ABTS method. For complementary characterization of cell extracts, a deoxyribose assay was carried out, as well as a bacteriophage P22/Salmonella-mediated approach. The microalga Scenedesmus obliquus strain M2-1 exhibited the highest (p > 0.05) total antioxidant capacity (149 ± 47 AAU) of intracellular extracts. Its scavenger activity correlated well with its protective effects against DNA oxidative damage induced by copper(II)-ascorbic acid; and against decay in bacteriophage infection capacity induced by H2O2. Finally, performance of an Ames test revealed no mutagenic effects of the said extract.

BACKGROUND The international marketing of native Brazilian fruits may benefit from research into discrimination between plants with particular properties. Plants with certain characteristics have strong potential for use in agroindustry and for the development of new processed products. In the current study, 12 uvaia plants (Eugenia pyriformis Cambess), native to Brazil, were geographically discriminated by chemometric methods, using nutritional composition, physicochemical characterization, bioactive compounds, and antioxidant capacity data. RESULTS Uvaia fruits presented good nutritional value, with a high moisture and carbohydrate content. All fruits presented a pH value lower than 4, being classified as highly acidic, and the total soluble solids (°Brix) ranged between 2.90 and 9.80. Some plants had a higher vitamin C content, and all the plants had a high bioactive compound content (phenolic and flavonoids) and antioxidant capacity in 1,1‐difenil‐2‐picrilhidrazil (DPPH), 2,2'‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) assays. Hydroethanolic solution was the best extraction solvent tested when compared with water and ethanol. Using principal component analysis, it was possible to discriminate among the plants in five different groups; however, just one group was responsible for higher antioxidant compound content. CONCLUSION In this work, 12 native uvaia plants were discriminated by their geographical origin using a chemometric approach. Genetic improvement based on natural selection could be accomplished with some of the plants to improve the quality of uvaia pulp and to develop new cultivars. © 2019 Society of Chemical Industry

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BACKGROUND: Feijoa [Acca sellowiana (Berg) Burret] is a Brazilian native fruit with few commercial-level plantations and high agroindustrial potential. A genotype evaluation experiment was conducted from 1996 onward, aiming to obtain fruits based on the agronomical parameters; however, the selection based on chemical composition had not been evaluated with respect to developing a new cultivar. Accordingly, the present study aimed to discriminate seven accessions of feijoa in terms of nutritional composition, phenolic compounds and antioxidant activity using multivariate analysis (principal component analysis and multivariate contrast), targeting the potential production of a new cultivar with better nutritional value and high antioxidant capacity. RESULTS: Feijoa husk presented high content of ashes, lipids, proteins, carbohydrates, phenolic compounds and antioxidant activity compared to feijoa pulp. However, only feijoa pulp was selected to multivariate analysis because it is the fruit edible part. Data variability was explained in 78% and the feijoa pulp accessions were discriminated into four groups related to their characteristics. The accession 5 discrimination can be explained by the high content of ashes, carbohydrates, soluble solids, phenolic compounds and antioxidant activity. Accession 6 was also discriminated by the high content of total acidity, pH and proteins, as well as a low content of soluble solids. CONCLUSION: Feijoa accessions may be indicated for increasing plant selection via hybridization with the other accessions, aiming to produce new cultivars with better nutritional composition and antioxidant capacity. For example, accession 5 is the most suited fruit for human consumption and is a potential plant with respect to becoming a new cultivar.