Antioxidant Activity Coefficient Research Articles

Exploring Cynara cardunculus L. by-products potential: Antioxidant and antimicrobial properties

Cynara cardunculus L. (cardoon), a perennial crop indigenous to the Mediterranean region, has gained recognition for its remarkable resilience to diverse weather conditions and its multifaceted applications across various industries, which includes the use of the flower as a vegetable rennet to produce some cheeses, as a source of biomass for energy, or its seed oil for human consumption, biodiesel, and animal feed. In some applications (e.g. biomass or seed production), when crop is harvested at the end of the growth cycle, the leaves remain as the main by-products, along with the flowers. In the context of a circular economy, the aim of this work was to undergone studies to determinate their biological properties (antioxidant and antimicrobial). Methanolic and ethanolic extracts of C. cardunculus L. (globe artichoke var. scolymus (L.) Fiori) and cultivated cardoon (var. altilis DC.)) leaves and flowers were characterised in terms of their polyphenol profile (total phenolic content (TPC), total flavonoid compounds (TFC), and ultra-high performance liquid chromatography coupled with time-of-flight mass spectrometry (UHPLC-ToF-MS)), antioxidant capacity (free radical DPPH inhibition system, β-carotene bleaching assay), and antimicrobial capacity (minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), antifungal). In addition, the cultivated cardoon leaves extracts were assessed before and after they were dried in an oven with forced air circulation to evaluate if this treatment affected their bioactive profile. Chlorogenic acid, apigenin, and luteolin were the most quantified of a total of sixteen compounds identified by UHPLC-ToF-MS. Cultivated cardoon dry leaf extract presented the best antioxidant capacity for both methanolic (EC50 = 0.8 mg/mL, antioxidant activity coefficient (AAC) = 279.67) and ethanolic (EC50 = 2.1 mg/mL, AAC = 448.06) extracts, compared to the cardoon flower extracts and the globe artichoke leaf extracts. Dried cultivated cardoon leaf extracts presented higher antioxidant capacity than fresh cultivated cardoon leaf extracts, but a greater number of polyphenolic compounds were identified in fresh cultivated cardoon leaf extract. The Gram-positive bacteria were more sensitive to the activity of both ethanolic and methanolic extracts than the Gram-negative and cultivated cardoon dry leaf ethanolic extract presented lower MIC and MBC values (125–2000 µg/mL) for most of the tested microorganisms, thus showing higher antimicrobial activity. As for the cultivated cardoon leaf extracts, the dried leaf extracts exhibited better antimicrobial activity, with lower MIC values, than the fresh leaf extracts. The extracts only demonstrated a slight inhibition against the fungi Aspergillus fumigatus. In conclusion, studies performed indicate that dried leaves maintain their biological activities compared to fresh leaves, and that flowers present significant biological activity which suggests the great potential of the by-products of this crop as a source of active compounds in different industrial applications (e.g. food industry).

Unlocking the Potential of Citrus medica L.: Antioxidant Capacity and Phenolic Profile across Peel, Pulp, and Seeds.

Citrus medica L. is a traditional citrus fruit that is rich in bioactive compounds and has the potential to be used as a natural source of food additives. This study aims to evaluate the antioxidant capacity and characterize the phenolic compounds present in the peels (including flavedo and albedo), pulp, and seeds of citron. The results showed that, compared to the other parts, the pulp had a substantially higher Antioxidant Activity Coefficient (AAC) of 168.2. The albedo and the seeds had significantly lower AAC values, while the green and yellow flavedo showed noteworthy results. O-coumaric acid was the predominant phenolic acid in all of the citron fractions; it was found in the highest concentration in albedo (37.54 µg/g FW). Flavanones and flavanols were the primary flavonoids in the pulp, peel, and seeds, with total flavonoid concentration ranging from ~9 µg/g FW in seeds to 508 µg/g FW in the pulp. This research offers significant insights into the antioxidant properties of this ancient fruit, emphasizing its potential applications as a natural source of antioxidants to be used in different applications.

THEORETICAL AND EXPERIMENTAL STUDIES OF ANTIOXIDANT PROPERTIES OF ANTIPYRINETHIOSEMICARBAZONE DERIVATIVES

Antipyrinethiosemicarbazone derivatives have been investigated as antioxidant in this work. The results of antioxidant activity coefficient (K) proved that all investigated compounds have good antioxidant activity. Investigation of the relation between antioxidant activity (K) and quantum-chemical parameters difference of heats of formation of a molecule and its cation radical ΔHf shows that the ΔHf values proportional with K values of investigated compounds.

Efficacy of Whey Protein Film Incorporated with Portuguese Green Tea (Camellia sinensis L.) Extract for the Preservation of Latin-Style Fresh Cheese.

Fresh cheese composition favors the growth of microorganisms and lipid oxidation, leading to a short shelf life. Whey protein concentrates can be used to produce active films in which green tea (Camellia sinensis L.) extract, rich in bioactive compounds, namely catechins, can be incorporated. Thus, the main objective of this study was to evaluate the efficacy of an edible active film, incorporated with green tea extract, to preserve goat and mixture (goat and sheep) fresh cheeses. Our results demonstrated that Portuguese green teas (antioxidant activity coefficient—AAC = 746.7) had superior antioxidant capacity to that of the evaluated Asian green tea (AAC = 650). Furthermore, green tea produced from the leaves of the new Portuguese Chá Camélia tea plantation had the highest potential to retain the antioxidant capacity (97.3%). Additionally, solid–liquid extractions led to extracts with higher antioxidant activity (AAC = 1500), but Soxhlet extractions presented higher yield (43%). Furthermore, the active film incorporated with Portuguese green tea extract exhibited a high antioxidant capacity (AAC ≈ 595.4). In addition, the active film effectively delayed the lipid oxidation of the evaluated fresh cheeses (3.2 mg MDA Eq/kg) when compared with the control (4.2 mg MDA Eq/kg). Moreover, the active films effectively inhibited the growth of microorganisms, especially E. coli (1.5 × 10 CFU/g), when compared with the blank (2.2 × 102 CFU/g). This study suggests that the new whey protein film incorporated with Portuguese green tea extract has the potential to be used to extend fresh cheese shelf life.

Кластерная характеристика вод, используемых объектами энергетики, по величине суммарной антикосидантной активности

The paper, using the cluster approach, executes water classification for cooling basins at the energy facilities by the summary of the antioxidant activity value. The index of water structure has been suggested which is defined by the general antioxidant activity and trophic coefficient of water. In case of technical use, it is possible to choose water with the lowest index values. The paper gives recommendations on the summary of the antioxidant activity of water values at the water intakes and outputs of CHP.

Free Radical Scavenging Activity of Some Legumes Hulls Extract and Its Efficacy on Oil Oxidative Stability.

Synthetic antioxidants have toxigenic effects, there is therefore growing interest in substituting them with natural antioxidants. Attention is being focused on extracting them from agricultural industry residuals to minimize costs. Legume seed hulls could be cheap sources of such natural antioxidants. This study aims to unravel potential free radical scavenging activity, antioxidant activity, and total phenolic and flavonoid contents of some legumes' hulls extracted by different solvents and evaluate their efficacy to enhance sunflower oil stability. Legume hulls extracted by different solvents were evaluated for their antioxidant activity coefficient (AAC), free radical scavenging activity [by 2,2-diphenyl-1- picrylhydrazyl (DPPH)], and phenolic and flavonoids contents. The protection factor and induction periods (rancimat test) of the highest activity extracts were evaluated. Sunflower seed hull ethyl acetate extract, lupine seed hull ethanol extract, and mung bean hull petroleum ether extract exhibited stronger DPPH scavenging activity, AAC, and protection factor values than other solvents. Ethyl acetate extracts of sunflower seed hulls showed an antioxidant and scavenging activity close (P>0.05) to that detected for α-tocopherol. Legume hulls may possess strong free radical scavenging and antioxidant activity. The analogous effect between sunflower hull extract and α-tocopherol make it a potential, cheaper substitute of α-tocopherol in food systems. The analogous effect between sunflower hull extract and α-tocopherol give it the potency to allow substitution at a concentration of 0.5% of sunflower hull ethyl acetate or 1% of lupine hull ethanol extract instead of 0.5% α-tocopherol to enhance induction periods and protection factors of sunflower oil.

Vitamin E as an inhibitor of oxidative damage to goose meat storage

The vitamin E effect on the lipid peroxidation product content and the endogenous antioxidant activity (at -18 C during the different types of storage) has been studied in goose meat. The goose meat of three samples has been used for storage. Meat of control sample has been obtained from geese fed by the standard diet. The 1st meat test sample of geese differs from the control group by two times higher content of vitamin E (40 mg / kg) in their diet from the 42nd to the 63rd day. Meat of the 2nd test sample obtained from the control group of geese is processed by a vitamin E solution (calculated at 100 mcg per g of meat) immediately before storage. The shelf life of meat is 210 days. It has been established that the intensive accumulation of the secondary lipid peroxidation products begins from the 90th day in the goose meat during its storage. In the goose diet a double increase of the vitamin E has contributed a significant (by 27.6%, p ≤ 0.05) TBA-AP decrease in the first meat test sample in comparison with the control group at the end of the experiment. The addition of vitamin E to the diet of geese has contributed the stabilization of the antioxidant pool in their meat. It has been confirmed by a 1.88-fold lower level of TBA-AP upon initiation of peroxide oxidation of Fe2+ and by the higher coefficient of antioxidant activity (36.0%, p ≤ 0.05) in this sample in comparison with the control on the 210th day. At the end of the experiment, the vitamin E content is higher 41.7 % (p ≤ 0.01) in the first sample than in the control, β-carotene - 15.0 % (p ≤ 0.05), and vitamin A is at the level of the control sample. Processed goose meat with a solution of vitamin E also provides reliable inhibition of peroxidation processes during the first half of the experiment. However, at the end of the experiment the content of TBA-AP reaches the level of the corresponding control indices in the 2nd test sample of meat. From the 120th day, there has been the more intensive use of endogenous antioxidants. The antioxidant activity coefficient decreasing to the control level on the 210th day in this meat sample is its conformation. The meat of this sample differs by a higher content of β-carotene from the control sample significantly (by 13.5%, p ≤ 0.05). Thus, to obtain a prolonged antioxidant effect during low-temperature storage of meat it is more advisable to add vitamin E to the diet of geese in the pre-slaughter period. Key words: geese, meat storage, lipoperoxidation products, antioxidant activity, vitamins E, A, β-carotene.

Electrochemical determination of antioxidant activity and HPLC profiling of some dry fruits

This study explored the antioxidant activities of eight dry fruits (almond, apricot, cashew, figs, peanut, pistachio, raisins, and walnut) against electrochemically generated superoxide anion radical (O2·−) in a cyclic voltammetric cell. The HPLC profiling of phenolic aglycones was carried out to determine the antioxidant compounds present in these extracts. Most of the dry fruits showed strong O2·− scavenging activity quantitated in terms of IC50 (concentration for 50% inhibition) and antioxidant activity coefficient (Kao). The antiradical activity followed the descending order: apricot > raisins > walnuts > figs > pistachio > peanut > almond > cashew. Based on experimental observations, the interaction mechanism of O2·− with the –OH-bearing compounds, present in the dry fruit extracts, has been proposed. This mechanism showed the relative proton transfer (H+) ability of all the dry fruit extracts. Electrochemically, it is reversible charge transfer followed by irreversible chemical step (ErCi). HPLC profiling showed seven phenolic aglycones (pyrocatechol, gallic acid, catechin, vanillic acid, caffeic acid, coumaric acid, and sinapic acid) in all the dry fruits. Among these, walnut was the only fruit that contained all identified compounds, while the rest contained gallic acid, catechin, caffeic acid, and coumaric acid as major compounds.

Ontogenetic features of redox reactions in the myocardium of geese

Under conditions of physiological stress of different aetiologies, cells of any organism undergo compensatory metabolic changes. The specificity of such changes primarily depends on functional and histochemical features of the tissues of the body. The purpose of this work was to describe the functioning of the main components of the oxidation-reduction system, (ORS, the Krebs cycle, and the antioxidant system) in the myocardium of geese under conditions of the physiological stress occurring during the transition from the embryonic to postnatal development. It has been experimentally established that in the second half of geese embryogenesis, the content of short-chain fatty acids is significantly increased and the content of long-chain polyunsaturated fatty acids in their myocardium decreases. During the first two weeks of the postnatal period, there are reversible changes in the fatty acid composition of this tissue. The second half of the embryogenesis is characterized by the activation of dehydrogenases of the Krebs cycle in the low variability of antioxidant enzyme activity. At the same time, the experiment demonstrated an increase in the antioxidant activity coefficient, with the exception of its significant reduction on the first day of postnatal ontogenesis. The functioning of the ORS in the myocardium of geese is characterized by the presence of correlations between the nature of the changes of 19 investigated components (dehydrogenases of the Krebs cycle, antioxidant enzymes, lipid peroxidation products, antioxidant activity coefficient, fatty acids, their total content and unsaturation) and structuring of the system into two clusters.

Improvement of the Antioxidant Activity of Fenugreek Protein Isolates by Lactococcus lactis Fermentation

This study investigated the antioxidant capacity of fenugreek protein isolate and its improvement by Lc. lactis fermentation through bioactive peptides production and the effect of molecular weight variation on fenugreek fractions antioxidant activity. Fenugreek protein isolate showed a significant increase of antioxidant and radical scavenging activity after 24 h of fermentation, by about 23.7, 42.9 and 40% for respectively antioxidant activity coefficient AAC, DPPH and ABTS radical scavenging activity. FI fermentation led to a hydrolysis of peptide bands with MW > 35 kDa and a generation of new bands with a MW < 25 kDa. A significant reduction in molecular-mass distribution of hydrolysates and a great increase of total free amino acids content, especially an increase on isoleucine, leucine, glutamic acid, serine, histidine, glutamine and lysine was noted. The infrared results showed that different reactions may take place after fermentation, and showed an increase of proteins, amides and aromatic compounds. However, fenugreek fraction (F2) with MW 15–50 kDa presented the highest activity instead of fraction (F1) with lower MW. Lc. lactis had the ability to degrade and convert fenugreek proteins into bioactive peptides that contribute positively in the improvement of antioxidant activity of FI and fractions. FI presents a significant antioxidant activity and thus, can be considered as a potential source of high added value natural antioxidants and may be employed as a functional food ingredient with good potential applications in food products.

Superoxide Scavenging and Antiglycation Activity of Rhinacanthins-rich Extract Obtained from the Leaves of Rhinacanthus nasutus.

Background:Oxidative stress and nonenzymatic protein glycation lead to serious diabetic complications that increase the risk of mortality. Rhinacanthus nasutus leaf crude extracts are previously reported for their antidiabetic, antiglycation, and antioxidant potential.Objective:The present study was performed to prepare a standardized rhinacanthins-rich extract (RRE) and evaluate its superoxide scavenging and antiglycation effects as compared to its marker compounds, namely, rhinacanthin-C (RC), rhinacanthin-D (RD), and rhinacanthin-N (RN).Materials and Methods:RRE was obtained by microwave-assisted green extraction along with a simple step of fractionation using Amberlite® column. RC, RD, and RN were isolated from the RRE using silica gel column chromatography. Superoxide scavenging activity was performed by cyclic voltammetry, and fructose-mediated human serum albumin glycation model was used for antiglycation activity. In silico studies were conducted to identify the structure-activity relationships of rhinacanthins.Results:On the basis of kinetic measurements, RRE exhibited the most potent antioxidant activity via ErCi mechanism, with a 50% inhibitory concentration (IC50) value of 8.0 μg/mL, antioxidant capacity of 39439 M−1, and binding constant of 45709 M−1. Antiglycation assay showed that RRE exhibited almost equivalent glycation inhibitory effect to that of RC, with IC50 values of 39.7 and 37.3 μg/mL, respectively, but higher than that of RD (IC50 of 50.4 μg/mL), RN (IC50 of 89.5 μg/mL), as well as the positive control, rutin (IC50 of 41.5 μg/mL).Conclusions:The potent superoxide scavenging and albumin glycation inhibitory effect of RRE rationalized its therapeutic application in various chronic diseases, especially in the complications of diabetes.SUMMARY Rhinacanthins-rich extract (RRE) exhibited potent superoxide scavenging activityRRE and rhinacanthin-C showed remarkable and comparable antiglycation effectRhinacanthins exhibited antiglycation activity by masking specific residues of albumin. Abbreviations used: RRE: Rhinacanthins-rich extract; RC: Rhinacanthin-C; RD: Rhinacanthin-D; RN: Rhinacanthin-N; IC50: 50% inhibitory concentration; Kao: Antioxidant activity coefficient; Kb: Binding constant; ErCi: Reversible electron transfer followed by an irreversible chemical reaction; DM: Diabetes mellitus; AGEPs: Advanced glycation end products; NMR: Nuclear magnetic resonance; HPLC: High-performance liquid chromatography; CV: Cyclic voltammetry; DMSO: Dimethyl sulfoxide; Ipa: Anodic peak current; Ipc: Cathodic peak current; HSA: Human serum albumin; MOE: Molecular operating environment; PASSonline: Online prediction of activity spectra for substances.

A Comprehensive Approach to Antioxidant Activity in the Seeds of Wild Legume Species of Tribe Fabeae

The benefits of polyphenols have been widely demonstrated in recent decades. In order to find new species with a high biological functionality, the antioxidant activity of the polyphenol extracts from seeds of 50 taxa of tribe Fabeae (Lathyrus, Lens, Pisum, and Vicia) from Spain has been studied. Considering the average concentration obtained from the data in the four genera of the Fabeae tribe, Pisum and Lathyrus show the highest average polyphenol concentration. The highest specific antioxidant activity as well as the antioxidant activity coefficient was observed in Pisum and Vicia. However, with respect to the total antioxidant activity, the highest average value was observed in Lathyrus and Pisum. The results obtained reveal that many of the wild taxa examined could be potential source of antioxidants.

Bioactive Compounds and Antioxidant Potential of Food Industry By-products in Egypt

The present study was carried out to examine the bioactive compounds and antioxidant potential of four food industry by-products (potato peel, cauliflower leaves, onion skin and mango peel) in Egypt. The total dietary fiber content for all tested by-products was ranged 27.15-42.71 g.100g-1, total carotenoids was 92.43- 412.14 mg.100g-1 and total phenolics was 1104-7129 mg GAE.100 g-1. The mango peel powder (MPP) was recorded the highest content of total dietary fiber and total carotenoids while red onion skin powder (ROSP) recorded the highest values of total phenolics. The food by-product extracts showed considerable differences in antioxidant activity when it was calculated by the four different methods used in this study. The antioxidant value (AOX, A/h), antioxidant activity (AA,%), oxidation rate ratio (ORR) and Antioxidant activity coefficient (AAC) were ranged 0.017-0.106, 81.23-96.98, 0.030-0.187 and 584.46-858.27, respectively. ROSP showed strong antioxidant activity followed by MPP, PPP and CLP, respectively. Correlation analysis indicated that there were a strong positive significant relationship (r2 = 0.741-0.962, p≤ 0.01) between total phenolics content and antioxidant activity and a positive significant relationship (r2 = 0. 604-0.718, p≤ 0.05) between total carotenoids content and antioxidant activity in all tested by-products. These correlations confirm that phenolic compounds mainly with carotenoids partially are responsible for the antioxidant activity of the tested by-products. In conclusion, data of the present study revealed that food industry by-products can be good sources of valuable bioactive compounds and antioxidants subsequently extend their potential uses in nutritional and therapeutic applications.

In-vitro Evaluation of Antioxidant Potency of Organic Extracts of Leaves of Corchorus depressus Linn.

Aim: Evaluation of free radical scavenging and lipid peroxidation inhibitory activities of commercially available leaves of Corchorus depressus Linn. by in-vitro chemical analysis. Methodology: Four different solvent extracts methanol-CDM, ethanol-CDE, ethyl acetate-CDEA and hexane-CDH were studied for their free radical scavenging activities using 1-diphenyl-2picrylhydrazyl (DPPH) radical assay method and the results were expressed as SC50 values. The lipid peroxidation inhibitory activities of three different concentrations (0.1, 0.5 and 1.0 mg/mL) were evaluated using β-carotene-linoleic acid model system and the results were expressed as oxidation rate ratio (ROR), antioxidant activity (AA) and antioxidant activity coefficient (CAA). L-Ascorbic acidAA, α-tocopherol-TOC and BHT were used as reference compounds. The total polyphenol contents of these extracts were also determined using Folin-Ciocalteau reagent. Results: The total polyphenol contents of extracts were decreased in the order of: CDM > CDE > CDEA >> CDH. In DPPH radical assay, CDM exhibited higher free radical scavenging activity Original Research Article Nessa and Khan; EJMP, 14(4): 1-13, 2016; Article no.EJMP.26006 2 (SC50: 216.27 μg/mL) than CDE (327.84 μg/mL) and CDEA (544.28 μg/mL). In comparison with natural antioxidants AA and TOC, the overall ranking was decreased in the order of: AA > CDM > TOC > CDE > CDEA >> CDH. In β-carotene-linoleic acid model system, CDM also exhibited higher protective activity against lipid peroxidation than other extracts as it exhibited lower ROR (0.4903 to 0.2752) and higher AA (50.96 to 72.47) and CAA (280.58 to 513.13) respectively amongst the studied extract. In comparison with BHT and TOC, CDM exhibited promising potency than TOC. Amongst the studied concentration 0.5 and 1.0 mg/mL were the mostly potent antioxidant against oxidation of linoleic acid. Conclusion: CDM exhibited most propitious antioxidant activities irrespective of the method undertaken in this study. CDM and CDE had protective activity against oxidation of fatty acid as well as both efficiently scavenged free radicals.

Synthesis and properties of feruloyl corn bran arabinoxylan esters.

To enhance the antioxidant activity and UV absorption coefficient of corn bran arabinoxylan (CAX), ferulic acid (FA) with this physiological activity is used to modify CAX. Corn bran arabinoxylan was extracted from corn bran according to alkaline hydrogen peroxide (AHP) method. FA was covalently linked to CAX by esterification in a two-step feasible synthesis to generate ferulic acid arabinoxylan esters (FA-CAX). The structure and molecular weight of FA-CAX were characterized by NMR and HPSEC, the degrees of substitution (DS) was determined by HPLC, and the ultraviolet (UV) coefficient of FA-CAX was tested by UV spectroscopy. The antioxidant activity of FA-CAX was investigated on the basis of 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical assay, and protecting ability of FA-CAX to UV-induced oxidative damage was tested using linolenic acid dispersion as stratum corneum lipid model. The results demonstrated that FA was attached to CAX successfully, and the inherent structure of CAX would not be broken during the process of the synthesis. FA-CAX-1 and FA-CAX-2 contained different amount of FA, with DS at 0.33 and 1.25, respectively, can absorb UV both at UVA and UVB. Moreover, FA-CAX-2 exhibited better antioxidant activity than FA-CAX-1 based on the two test methods. Ferulic acid modified CAX had significant antioxidant ability and UV absorption coefficient. And higher amount of FA leads to higher antioxidant activity and stronger UV absorption and stability. With increasing amount of FA attached to CAX, the antioxidant activities were better and the UV absorption was stronger and more durable.

Chemical Composition of Cyperus rotundus L. Tubers Essential Oil from the South of Tunisia, Antioxidant Potentiality and Antibacterial Activity against Foodborne Pathogens

The chemical composition of Cyperus rotundus L. tubers essential oil from the South of Tunisia was analyzed using GC-FID and GC-MS. Fifty compounds were identified representing 84.6% of the total oil. A new chemotype was found in Tunisia. This essential oil was characterized by sesquiterpenes abundance (78.3%) mainly represented by cyperene (15.2%) and cyperotundone (19.7%). The essential oil (EO) was further fractionated into three fractions (F1: n-pentane, F2: n-pentane/diethyl ether (95/5) and F3: diethyl ether). The antioxidant activity of the EO and its fractions was tested using the1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging test and β-carotene bleaching method. Results showed that the whole EO was more active than the fractions with an effective concentration (EC) of 0.85 ± 0.03 mg/mL and an antioxidant activity coefficient (AAC) of 396.0 ± 2.4. The antimicrobial activity of the EO and its fractions was evaluated using the disc diffusion method against six foodborne pathogens and results showed that Staphylococcus aureus was the most inhibited bacterium with an inhibition diameter of 15.2 ± 0.8 mm for the whole EO.

Antioxidant and radio-protective activities of lemon grass and star anise extracts

Aqueous extracts of Lemon grass (Cymbopogon citratus) and Star-anise (Illicium verum) were prepared and evaluated for antioxidant activity using various in vitro assay systems. The extracts, even at low concentrations, worked as efficient scavengers of DPPH (IC50 of 72–90 µg/ml), and superoxide radicals (77–87% scavenging). The antioxidant activity coefficient as determined by β-carotene bleaching assay was high (600–800). Both the extracts exhibited high reducing power indicating good antioxidant potential. Lipid peroxidation, monitored as thiobarbituric acid-reactive substance (TBARS) were significantly lower (p<0.05) in irradiated meat containing these extracts. Antioxidant potential of Star anise extract was better than Lemon grass extract. The extracts were able to protect against radiation induced DNA damage in pBR322 plasmid.

Phenolic profile and antioxidant properties of a crude extract obtained from a brewery waste stream

The main aims of this study were to determine the phenolic profile of a crude extract obtained (at pilot scale) from a brewery waste stream and to evaluate the antioxidant activity of the extract. The total phenolic content was determined by the Folin–Ciocalteu assay, which revealed that 50% of the extract comprised phenolic compounds. The polyphenols, identified and quantified by RP-HPLC–DAD and HPLC-ESI–TOF-MS, were mainly flavonoids (catechin, epicatechin, gallocatechin, epigallocatechin, quercetin) and phenolic acids (ferulic acid, p-coumaric acid, caffeic acid, protocatechuic acid). The crude extract displayed a high DPPH radical scavenging activity (0.18g/L), similar to that of BHA (0.248g/L) and higher than that of BHT (2.54g/L). All three tested products displayed a similar ability to decrease oxidative bleaching of β-carotene (antioxidant activity coefficient of 623.8 for the crude extract, 653.3 for BHA, 559.6 for BHT). This type of brewery waste stream may be a promising source of natural antioxidants to replace the synthetic antioxidants currently used in the food industry.

Phenolic composition and antioxidant activity of Southern Italian monovarietal virgin olive oils

AbstractThe phenolic composition and antioxidant activity of several monovarietal extra virgin olive oils used as blenders for the production of Collina di Brindisi protected designation of origin (PDO) oil, produced between December 2008 and January 2009 using two‐phases or three‐phases extraction system, were evaluated and compared with other manufacturer products designated as PDO. Oils were taken from the most representative ones industrial oil mills in the PDO geographical area. The parameters assessed were free acidity, peroxide value, K232 and K270 indices, organoleptic characteristics, total phenolic content (TPC), phenolic profile, and antioxidant activity coefficient (AAC). The phenolic contents and profiles of the monovarietal oils showed remarkable differences with respect to PDO oils. The variables that exerted a major influence on phenols concentration were the maturity degree of olives (December&gt;January), followed by the extraction system (two‐phase&gt;three‐phase), and place of growing. The Pearson r correlation index showed that AAC was positively correlated with TPC, p‐coumarate, and 3,4‐DHPEA‐EA, and negatively correlated with peroxide value.Practical applications: The results provide detailed information about: (i) the phenolic composition and the AAC of several monovarietal extra virgin olive oils used as blenders for the production of a PDO oil; (ii) the impact of genetic variability, place of growing, olive maturity degree, and extraction technology on oil phenol compounds; and (iii) the relationships among each phenolic compound and AAC, and their potential utilization as analytical index of antioxidant activity. It is important to study the phenolic compounds and antioxidant activity of monovarietal extra virgin olive oils used to produce PDO oil and to compare with the relative PDO samples in order to define a possible analytical tool able to verify what is stated in the label for consumer information and protection.

Antioxidant activity coefficient, mechanism, and kinetics of different derivatives of flavones and flavanones towards superoxide radical

A systematic investigation of the electrochemically generated superoxide radical (O&lt;sub&gt;2&lt;/sub&gt;&lt;sup&gt;●&amp;ndash;&lt;/sup&gt;) has been conducted in the presence of some flavonoids. Cyclic voltammetry was used to generate O&lt;sub&gt;2&lt;/sub&gt;&lt;sup&gt;●&amp;ndash;&lt;/sup&gt; by reducing the molecular oxygen in DMSO at room temperature. The scavenging of the radical was monitored by the decrease in anodic or/and cathodic currents while linearly increasing the concentration of the flavonoid. The strength of interaction was quantified in terms of the binding constant (K&lt;sub&gt;b&lt;/sub&gt;)values ranging from 1 &amp;times; 10&lt;sup&gt;2&lt;/sup&gt; and 5 &amp;times; 10&lt;sup&gt;3&lt;/sup&gt;M&lt;sup&gt;&amp;ndash;1&lt;/sup&gt;. The antioxidant activity coefficient (K&lt;sub&gt;ao&lt;/sub&gt;) was calculated from the linear part of the plot of &amp;lsquo;current decrease vs. flavonoid concentration&amp;rsquo;. Radical scavenging mechanism of the antioxidant was proposed and discussed in terms of the structure activity relationship. Nicholson-Shain method was employed to estimate the bimolecular homogeneous kinetics and on this basis control use of antioxidant is pointed out. &amp;nbsp;