Authors:Rita Csepregi, Tímea Bencsik and Nóra Papp
Anthyllis vulneraria L., Fuchsia sp., Galium mollugo L., and Veronica beccabunga L. were selected to analyse the phenolic content and the antioxidant activity by ferric ion reducing antioxidant power (FRAP) and trolox equivalent antioxidant capacity (TEAC) assays. The highest polyphenol, tannin, and flavonoid contents were measured in Fuchsia species (7.40 ± 0.8, 5.62 ± 0.7 and 0.72 ± 0.1 g/100 g dry weight), while the lowest values were detected in Anthyllis vulneraria (0.68 ± 0.02, 0.17 ± 0.03 and 0.45 ± 0.01 g/100 g dry weight) and Galium mollugo (1.77 ± 0.05, 0.49 ± 0.04 and 0.16 ± 0.06 g/100 g dry weight). The leaf extract of Fuchsia sp. had the highest, while the herb of A. vulneraria had the lowest antioxidant effect measured by both methods, which is probably related to total polyphenol, tannin, and flavonoid contents.
Authors:J. Pokorná, P. R. Venskutonis, V. Kraujalyte, P. Kraujalis, P. Dvořák, B. Tremlová, V. Kopřiva and M. Ošťádalová
Coffee beans contain a large amount of antioxidants, which are subjected to various changes during roasting. In this study, antioxidant potential of raw and roasted to different degree (light, medium, dark) C. arabica and C. robusta coffee beans was evaluated by the four antioxidant assay methods, TPC, FRAP, TEAC, and DPPH˙.
The obtained results revealed significant differences between the coffee types, roasting degree, and antioxidant activity assessment methods. FRAP and TPC appeared to be the most appropriate methods for revealing the differences in antioxidant potential of different coffee types and the effects of roasting. The results obtained by these methods were in good correlation. ABTS and DPPH? methods are not enough sensitive for the determination of roasting degrees.
In general, based on statistical data evaluation, antioxidant activity is more dependent on the coffee type than on the degree of roasting, however, the selection of analytical method may also be significant.
Authors:VJ Clemente-Suárez, J Mielgo-Ayuso, JL Quiles, A Varela-Lopez and P Aranda
hemoglobin, mean cell hemoglobin concentration, lymphocytes, neutrophils, monocytes, trolox equivalent antioxidant capacity (TEAC), α-tocopherol, and lactate were evaluated after a 180-min ultraendurance running probe in three different groups of Wistar rats
Authors:JA Bruno, CH Feldman, DW Konas, AL Kerrihard and EL Matthews
(TEAC). Following the in vitro testing, we hypothesized that brachial artery flow-mediated dilation (FMD), a test of in vivo endothelial function, would be greater following the consumption of pasta prepared with SCF40 than 100% semolina flour (SEM
Authors:S. Valcheva-Kuzmanova, V. Gadjeva, D. Ivanova and A. Belcheva
fruit juice (AMFJ) used in this experiment was very rich in phenolic substances, anthocyanins being the main flavonoid group. The antioxidant action of AMFJ was determined in vitro through measuring its Trolox equivalent antioxidant capacity (TEAC), superoxide dismutase (SOD)-like activity and catalase (CAT)-like activity. The TEAC of AMFJ was 63±0.8 mM. The SOD-like activity of 1 ml AMFJ was equivalent to that of 230.3±8.4 U SOD and was equal to that of 12.3 mg L-ascorbic acid and 11.4 mg Trolox, respectively. The CAT-like activity of 1 ml AMFJ was equivalent to the activity of 3223.5±91.3 U CAT and was equal to that of 6.4 mg L-ascorbic acid, while Trolox did not show such an activity. The pronounced antioxidant action of AMFJ is probably due to its high content of phenolic compounds.
Authors:E. Ivanišová, K. Meňhartová, M. Terentjeva, L. Godočíková, J. Árvay and M. Kačániová
The aim of the present study was to determine the microbial composition, antioxidant activity, and content of phytochemicals in prepared kombucha tea beverage. Microbiota was identified by MALDI-TOF mass spectrometry, antioxidant activity of beverage was tested by ABTS and phosphomolybdenum method, the total content of phytochemicals (polyphenols, flavonoids, and phenolic acids) was measured by colorimetric methods. The major phenolic acids, flavonoids, and methylxanthines were detected by high performance liquid chromatography (HPLC). Candida krusei, Sphingomonas melonis, Sphingomonas aquatilis, Brevibacillus centrosporus, and Gluconobacter oxydans were the most abundant microorganisms. Antioxidant activity of kombucha tested by ABTS and phosphomolybdenum method was 1.16 mg TEAC/ml and 2.04 mg TEAC/ml, respectively, which values were higher than in black tea 0.67 and 0.81 mg TEAC/ml, respectively. Also, content of total polyphenols (0.42 mg GAE/ ml), flavonoids (0.13 mg QE/ml), and phenolic acids (0.19 mg CAE/ml) was higher in kombucha than in black tea (0.18 mg GAE/ml; 0.02 mg QE/ml; 0.05 mg CAE/ml, respectively). Gallic, chlorogenic, syringic, and protocatechuic acids, and rutin and vitexin from flavonoids were dominant in kombucha beverage detected by HPLC. Strong difference in caffeine contents, 217.81 µg ml−1 (black tea) and 100.72 µg ml−1 (kombucha beverage), was observed. The amounts of theobromine were similar in black tea and kombucha, but theophylline was detected only in black tea in trace amount (0.52 µg ml−1).
Authors:F.J. García-Alonso, I. Navarro-González, G. Ros and M.J. Periago
The aim of this research was to assess the total antioxidant activity (TAA) of lipophilic (Lextr) and hydrophilic (Hextr) tomato extracts using in vitro chemical tests and cell-based assays, focusing on possible synergistic actions between tomato antioxidants. Both Hextr and Lextr were HPLC analysed for their carotenoids, phenolic compounds, and ascorbic acid contents. For the evaluation of TAA, extracts were assayed alone or in combination using in vitro chemical tests (TEAC, FRAP) and cell-based (CAA) assays using human hepatoma (HepG2) and human histiocytic lymphoma (U937) cells. The only carotenoid detected in Lextr was lycopene, while a mixture of phenolic compounds (chlorogenic acid, caffeic acid, and rutin) was identified in Hextr. Ascorbic acid was not found either in Hextr or in Lextr. Upon extract combination (1:1, v/v), the FRAP assay revealed additive action between Lextr and Hextr, whilst a slight synergistic action was observed in TAA as measured by the TEAC assay. Synergistic action was better revealed when TAA was analysed using either U937 or HepG2 cells. This could be explained by the presence of a multiphase media (cell membrane and extra- and intracellular media) that might facilitate the distribution and interaction of antioxidants with different polarities and different mechanisms of action.
Authors:B. Pliszka, G. Huszcza-Ciołkowska, E. Januszewicz and I. Warmińska-Radyko
The purpose of the study has been to determine the stability, microbiological quality, and antioxidant properties of extracts from the berry fruits of black chokeberry, American blueberry, and bilberry. In addition, the content of polyphenolic compounds in the extracts was analysed and the ratio of the content of anthocyanins to total phenols (the ACY/TP ratio) was determined. Extracts from the fruits of black chokeberry, American blueberry, and bilberry had different stability, microbiological quality, content of polyphenols, and ACY/TP ratio. The highest stability of anthocyanins and the highest ACY/TP ratio were determined in the extracts from bilberry, and the lowest ones appeared in the extracts from American blueberry. The stability of anthocyanins tended to decline during storage, either cooled or frozen. No bacteria were found in the berry fruit extracts although small contamination with microorganisms (yeast, mould) was detected. The highest content of polyphenolic compounds was determined in the extracts from black chokeberry and the lowest one in the extracts from American blueberry. The antioxidant activity of the extracts ranged from 1.99 to 2.41 TEAC mmol TR/100 g, and the antiradical activity varied from 84.91% to 86.30%. The applied extraction method with citric acid had a positive influence on the stability, microbiological quality, and antioxidant properties of the fruit extracts.