Cellular Antioxidant Activity Value Research Articles

Insights into tissue-specific anthocyanin accumulation in Japanese plum (Prunus salicina L.) fruits: A comparative study of three cultivars

In the present study, three matured Japanese plum cultivars with different colored peel and flesh were selected to mine the key transcription factors regulating anthocyanin formation in tissues. Results showed that PsMYB10 was correlated with structural genes C4H, F3H, and ANS. PsMYB6 could positively regulate C4H (r = 0.732) and accumulated anthocyanins in Sanhua plum’s flesh. Sanhua plum has the highest phenolic and anthocyanin contents (10.24 ± 0.37 gallic acid equivalent mg g−1 dry weight (DW) and 68.95 ± 1.03 μg g−1 DW), resulting itself superior biological activity as 367.1 ± 42.9 Trolox equivalent mg g−1 DW in oxygen radical absorbance capacity value and 72.79 ± 4.34 quercetin equivalent mg g−1 DW in cellular antioxidant activity value. The present work provides new insights into the regulatory mechanism of tissue-specific anthocyanin biosynthesis, confirming the pivotal role of anthocyanins in the biological activity of plums, providing essential support for the development of horticultural products enriched with anthocyanins.

Potato protease inhibitors, a functional food material with antioxidant and anticancer potential

Potato protease inhibitors (PPIs), as the main component of potato protein isolate, have good safety, nutrition and great market potential. The antioxidant and anticancer properties of PPIs were evaluated with cell-based biological assays. The results showed that when the concentration of PPIs was 5 mg/mL, the peroxyl radical scavenging value was (2119 ± 204) mg VCE/100 g, and the cellular antioxidant activity values were (45.83 ± 3.5) (no PBS wash) and (33.25 ± 4.4) µmol QE/100 g (PBS wash). Cells pretreated with PPIs could significantly prevent the oxidative damage induced by H2O2, inhibit the morphological changes of cells and maintain the integrity. Furthermore, PPIs had selective anti-proliferative effects on GIST882 cells (IC50 = (10.53 ± 3.87) mg/mL) and demonstrated potent inhibition of the growth, migration and invasion of cancer cells. These findings provide a scientific basis for PPIs as promising candidates for functional foods to aid in the prevention of oxidative damage and cancer.

Stability and antioxidant activity of phenolic compounds during in vitro digestion.

The impact of phenolic compounds on the human body depended on the type, content, bioavailability, and antioxidant activity. After digestion, different phenolic compounds had different changes of bioavailability and antioxidant activity, which needed to be considered in the application. In this experiment, the structural stability and antioxidant activity of 27 phenolic compounds (phenolic acids, flavonols, flavonoids, and flavanones) were investigated during the in vitro simulated digestion. This experiment eliminated the influence of food matrix, provide a basis for regularity for the changes of phenolic substances in different materials. Results showed that the bioaccessibility of phenolic compounds with different structures varied, and there was a conformational relationship between the structure and stability. After oral digestion, most of the phenolic compounds underwent degradation and the cellular antioxidant activity (CAA) values decreased to a large extent (p<0.05). After gastric digestion, the content (p>0.05) and CAA values (p<0.05) of most phenolic compounds increased. However, after intestinal digestion, the phenolic compounds were degraded to a greater extent, and different structures of phenolic compounds had different changes in CAA values (p<0.05). In general, the CAA values of most phenolic compounds after in vitro digestion were lower than the initial value. The 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ehylbenzthiazoline-6-sulfonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) values of phenolic acids and flavonols decreased after in vitro simulated digestion (p<0.05), while the values of DPPH, ABTS, and FRAP of most flavonoids (p<0.05) increased. The increased oxygen radical absorption capacity (ORAC) values were found in most phenolic acids, flavonols, and flavonoids (p<0.05), and most flavanones showed unremarkable changes in ORAC values (p>0.05). In general, the changing trend of chemical-based antioxidant activity was consistent with the content of phenolic compounds.

Quantification of Phytochemicals, Cellular Antioxidant Activities and Antiproliferative Activities of Raw and Roasted American Pistachios (Pistacia vera L.).

The consumption of pistachios has been linked to many potential health benefits. Phytochemicals in pistachios, including phenolics, vitamin E and carotenoids, have been considered to make contributions to the health benefits. The objectives of this study were (1) to explore the phytochemical profiles (total phenolics and total flavonoids, including both free and bound forms), selected phytochemicals, vitamin E and carotenoids of raw and roasted pistachios; (2) to determine total antioxidant activity and cellular antioxidant activity (CAA); and (3) to explore antiproliferative activities of pistachio extracts against human breast, liver and colon cancer cells in vitro. Both raw and roasted pistachios contained high total phenolics, at 479.9 ± 10.2 (raw) and 447.9 ± 9.4 (roasted) mg GAE/100 g, respectively, and high flavonoids, at 178.4 ± 10.6 (raw) and 144.1 ± 7.4 (roasted) mg GAE/100 g, respectively. The contributions of the free form to the total phenolics in pistachios were 82% (raw) and 84% (roasted), respectively, and the contributions of the free form to the total flavonoids in pistachios were 65% (raw) and 70% (roasted), respectively. Gentisic acid and catechin were the major phenolics in raw and roasted pistachios, respectively. Both raw and roasted pistachios had similar total antioxidant activity evaluated by Oxygen-Radical-Scavenging Capacity (ORAC) assay, at 7387.9 ± 467 (raw) and 7375.3 ± 602 (roasted) μmol TE/100 g, respectively. Both raw and roasted pistachio extracts exhibited cellular antioxidant activity inhibiting peroxyradical radical-induced oxidation, with CAA values of 77.39 ± 4.25 (wash) and 253.71 ± 19.18 (no wash) μmol QE/100 g of raw pistachios and 115.62 ± 3.02 (wash) and 216.76 ± 6.6 (no wash) μmol QE/100 g of roasted pistachios. Roasted pistachios contained more vitamin E when compared with raw pistachios, while raw pistachios contained more carotenoids than the roasted pistachios. Additionally, the free form of roasted pistachios extracts exhibited superior antiproliferation activity against HepG2, Caco-2 and MDA-MB-231 cancer cells in a dose-dependent manner, with EC50 34.73 ± 1.64, 36.66 ± 3.3 and 7.41 ± 0.82 mg per mL, respectively. These results provided new knowledge about the phytochemical profiles, antioxidant activity, cellular antioxidant activity and antiproliferative activity of raw and roasted pistachios.

Phenolics Profile and Antioxidant Activity Analysis of Kiwi Berry (Actinidia arguta) Flesh and Peel Extracts From Four Regions in China.

The kiwi berry (Actinidia arguta) has been widely studied because of its rich phenolic, flavonoid, and vitamin C contents. Numerous reports have demonstrated that fruit peels contain higher phenolic content and antioxidant activity than that of flesh. In this study, the phytochemical content and antioxidant activities of peel and flesh extracts of six kiwi berries were analyzed from four regions (namely, Dandong, Benxi, Taian, and Tonghua) in China. The antioxidant activity was determined using the peroxyl radical scavenging capacity (PSC) and cellular antioxidant activity (CAA) assays. The phenolic, flavonoid, and vitamin C contents of kiwi berry peel were 10.77, 13.09, and 10.38 times richer than that of kiwi berry flesh, respectively. In addition, the PSC and CAA values of kiwi berry peel were higher than those of kiwi berry flesh. The analysis of the separation and contents of phenolics were performed by the high-performance liquid chromatography (HPLC)-diode-array detectormass spectrometry/mass (DAD-MS/MS) system, and the results illustrated that protocatechuic acid, caffeic acid, chlorogenic acid, and quinic acid were the major phenolic compounds. In conclusion, this study indicated that kiwi berry peel contains a rich source of antioxidants. These data are of great significance for the full development and utilization of kiwi berries in these four regions of China to produce nutraceutical and functional foods.

Effects of different pesticides treatments on the nutritional quality of kiwifruit.

Pesticides are widely used in the process of kiwifruit growth to promote fruit expansion. This study was aimed to assess the effects of pesticides on the quality of kiwifruit by applying high and normal concentrations of forchlorfenuron (CPPU) and thidiazuron (TDZ) to "Xuxiang" (XX) green kiwifruit and "Jinyan" (JY) gold kiwifruit. Sixty kiwifruit trees were used to comprehensively evaluate the effects on the pulp and whole kiwifruit. In addition to the weight gain effect and basic physical-chemical properties (vitamin C, total protein, glucose and fructose, organic acids), the main nutritional qualities (in vitro and cellular antioxidant activity (CAA), and dietary minerals) were also evaluated. The vitamin C content of XX was not affected by pesticides, but the use of CPPU reduced vitamin C of JY pulp by 23% (p<0.05). Pesticides did not reduce the antioxidant values of XX pulp in vitro but significantly reduced CAA values (32%-47%). In JY pulp, pesticides treatments had no significant effect on antioxidant values in vitro except that CPPU treatments significantly reduced the ferric reducing antioxidant power (FRAP) value by 21% (p<0.05). Reasonable use of pesticides can effectively improve taste of kiwifruit, increasing kiwifruit weight and the content of certain nutrients. PRACTICAL APPLICATION: Based on observed changes in nutritional components, CPPU may be more suitable for XX while TDZ may be more suitable for JY. The significance of this study may affect kiwifruit farmers and ultimately help improve the sensory quality of kiwifruit.

Effects of chain length and saturation of triglycerides on cellular antioxidant activity of vegetable oil emulsions

In this study, the cellular antioxidant activity (CAA) of α-tocopherol and γ-oryzanol was determined in two typical oil bases, namely rice bran oil base (RBOB) with long-chain unsaturated triglycerides and coconut oil base (CNOB) with medium-chain saturated triglycerides. The results showed that α-tocopherol and γ-oryzanol exhibited significantly higher CAA values in CNOB. In order to further explore the mechanism, glyceryl trioleate (GLT) and medium chain triglycerides (MCT) with similar structures to RBOB and CNOB respectively were added and compared. It was found that long-chain unsaturated triglycerides (RBOB and GLT) in emulsions exhibited lower CAA values than medium-chain saturated triglycerides (CNOB and MCT), though the former presented higher cellular uptake of minor constituents. It was speculated that unsaturated bond tended to be attacked by free radicals to initiate an oxidative chain reaction in HepG2 cells resulting in lipid peroxidation, thus depleted more antioxidants. Overall, these findings provided useful reference for further developing the production and processing of vegetable oil for better stability.

The bioactive compounds and cellular antioxidant activity of Herbaceous peony (Paeonia lactiflora Pall) seed oil from China.

Herbaceous peony (HP) seed oil has been consumed in some regions of China, yet little information is available on its bioactive composition and antioxidant activity. This study aimed to evaluate the fatty acid compositions, micronutrients contents, and cellular antioxidant activity (CAA) of HP seed oil from five varieties. Results indicated that this oil had high percentages of monounsaturated (32.15 to 45.92%) and polyunsaturated fatty acids (58.65 to 61.95%), and the α-linolenic acid C18:3 was the highest in Fushao seed oil. Additionally, the high concentrations of tocopherol and phytosterol were found in all seed oils, and 10 individual polyphenols have been evaluated. Fushao seed oil had the highest polyphenols levels and showed higher CAA values. Both hierarchical cluster analysis and principal component analysis have been used to distinguish HP seed oil from different varieties. This information is valuable for the nutritional value and industrial interest of HP seed oil in China. PRACTICAL APPLICATION: This research showed that Herbaceous peony seed oil had higher levels of minor components and polyunsaturated fatty acids, especially, α-linolenic acid, and our results could also provide the theoretical foundation for the health benefits of Herbaceous peony seed oil as the vegetable oils. However, the variety of Herbaceous should be considered when extracting oil from Herbaceous peony seeds in the industry.

Enzymatic preparation and antioxidative activity of hydrolysate from Rice bran protein

As a protein-rich resource, rice bran protein has not been developed and utilized effectively. In this study, the optimal condition to prepare hydrolysate from rice bran protein was determined by screening protease and conducting single factor experiments along with response surface methodology. Optimal hydrolysate was prepared to further investigate its chemical (DPPH, ABTS, Fe2+) and cellular antioxidative activity. Finally, its amino acid composition was explored. In the results, alcalase was selected and other parameters were: pH 8.5, enzyme-to-substrate ratio 0.38%, and substrate concentration 6%. It was proved that the hydrolysate was an excellent DPPH (EC50 = 5.647) and ABTS (EC50 = 0.195) scavenger as well as good Fe2+ (EC50 = 1.765) chelator, showing directly proportional relationships with dose. In cellular antioxidant activity (CAA) assay, the CAA value reached 31.76% at the concentration of 1 mg/mL and the increasing use of rice bran protein hydrolysate significantly improved CAA. Amino acid composition analysis showed that the hydrolysate was rich in glutamic acid (13.02%), aspartic acid (6.68%), arginine (3.34%) and many kinds of hydrophobic amino acids which contribute to the antioxidant property. This research revealed the potential application of rice bran protein hydrolysate in natural antioxidants.

Physical properties and cellular antioxidant activity of vegetable oil emulsions with different chain lengths and saturation of triglycerides

Lipid concomitants are the main trace substances that determine the oxidative stability of oils. Over 90% of oils are composed of triglycerides, which affect oxidative stability. Oils typically enter living organism as emulsions. This study investigated the physical properties and cellular antioxidant activity (CAA) of emulsions in two model oils, namely, rice bran oil (RBO) with long-chain unsaturated triglycerides and coconut oil (CNO) with medium-chain saturated triglycerides. The results were as follows: the mean particle sizes were all approximately 250 nm; the polydispersity index (PDI) values were below 0.2; and the zeta potential values were more negative than −30 mV. The droplet size distribution of CNO emulsions was more concentrated than that of RBO emulsions. Rice bran oil-S (RBO-S) emulsions exhibited the highest CAA value, but the CAA value of coconut oil-C (CNO–C) emulsions was higher than that of rice bran oil-D (RBO-D) emulsions, indicating that CAA was influenced by the combined effect of triglycerides and minor constituents. Moreover, the medium-chain saturated triglycerides in vegetable oil emulsions resulted in a stronger CAA than that of long-chain saturated triglycerides.

Evaluation of the Antioxidant Properties of Micronutrients in Different Vegetable Oils

AbstractMicronutrients (tocols, sterols, and total phenolic) and antioxidant activities of 15 varieties of common vegetable oil samples obtained from different countries are investigated. All methanol extracts are assayed for total antioxidant ability and cellular antioxidant activity (CAA) using oxygen radical absorbance capacity (ORAC) method and CAA assay. CAA has been widely used in the evaluation of food antioxidants recently. It quantifies antioxidant capacity utilizing a HepG2 cell model, which is more biologically representative. Linseed and sesame oils show much higher CAA values than the others tested; however, levels of walnut, sunflower, and coconut oils are extremely low, which are hard to be quantified. A significant correlation between the ORAC and CAA values and total phenolic content (p &lt; 0.05) is observed. High‐phenolic olive oil has the highest level of phenolics and the highest ORAC, while linseed oil has the highest CAA value. Based on this, choosing proper edible oil consumption may reduce oxidative damage of human body and promote the precision processing of edible oil such as retaining beneficial ingredients moderately.Practical Application: This study demonstrates the evaluation of the universality of vegetable oils by the cellular antioxidant model and provides a data reference for the selection of edible oils with excellent antioxidant properties.

Novel Antioxidant Peptides Purified from Mulberry (Morus atropurpurea Roxb.) Leaf Protein Hydrolysates with Hemolysis Inhibition Ability and Cellular Antioxidant Activity.

Neutrase-hydrolysates hydrolyzed from mulberry leaf proteins were separated by ion exchange chromatography, gel filtration chromatography, and semipreparative reverse-phase HPLC. Purified fractions were analyzed for their radical scavenging activity, hemolysis inhibition ability, and cellular antioxidant activity (CAA). Three new antioxidant peptides, P1 (SVL, 317 Da), P2 (EAVQ, 445 Da), and P3 (RDY, 452 Da), were obtained from the most active HPLC fraction (R1) and identified using UPLC-QTOF-MS. These three peptides were then synthesized, and their antioxidant activities were analyzed. P1 and P2 had no ability to inhibit hemolysis of erythrocytes but did show antioxidant activity on HepG2 cells. P3 showed the highest hemolysis inhibition ability (92%) and CAA value (2204 μM QE/100 g peptide). The Tyr residues at the C-terminal region play an important role in the antioxidant activity in P3. Thus, the natural peptide R1 and synthesized P3 could be used as antioxidants and might be promising components of functional foods.

Effect of enzymatic digestion, chemical and boiled water extraction techniques on apparent antioxidant bioactivities of apple peel

Apple peel, is rich in bioactive phytochemicals with a wide of range of biological activities and health benefits. Phenolics, antioxidant and anti-proliferative properties of apple peel were evaluated using a simulated in vitro digestion and compared with a chemical extraction method to explore how the nature products by digestion to obtain a magnitude of antioxidant benefits. Digested samples were subjected to anti-proliferative evaluation against human liver cancer cells. Furthermore, antioxidant of digested apple peel was evaluated via the cellular antioxidant activity (CAA) method. Results revealed that the phenolic compounds obitained from enzymatic digestion were different from the chemical extracts. The contents of some component of phenolic acids and flavonoids (such as Q-3-G, Phloridzin, coumaric acid) in the digestion method were higher than other methods, which was contributed to higher in vitro antioxidant activity than other methods. Apple peel treated with cellulose-digestion also showed the highest CAA (No PBS wash) value. This finding indicated that enzyme-digestion of phytochemical rich materials could provide additional health benefits from natural products and would be a healthy strategy for food processing.

Effect of Stevia rebaudiana Bert. Addition on the Antioxidant Activity of Red Raspberry (Rubus idaeus L.) Juices

The demand for antioxidant-rich beverages is steadily expanding. At the same time, the possibility of manufacturing products with reduced sugar content, sweetened with natural ingredients, represents a decisive aspect of obtaining quality products with health benefits. Stevia rebaudiana Bertoni (stevia) is a natural sweetener that can help to control caloric intake and is also a good source of antioxidant compounds. The present study was designed to assess the feasibility of producing high-quality berry juices sweetened with dry-grinded stevia leaves or their crude extract. The effect of the stevia supplementation on the antioxidant activities of raspberry juices was determined at two different production steps by means of the Folin–Ciocalteu, the oxygen radical absorbance capacity (ORAC), and the cellular antioxidant activity (CAA) assays. The addition of stevia significantly increased the antioxidant activity of the juices and resulted in significantly higher ascorbic acid and total phenolic content. A positive correlation was observed between ORAC, CAA, and total phenolic values. These findings show that supplementation with stevia not only promotes a healthy diet by reducing sugar intake but may also enhance the antioxidant potential of the beverage.

Antioxidant properties of Etlingera pubescens, an edible ginger plant endemic to Borneo

Zingiberaceae is a family that consists of many edible ginger plants. Etlingera pubescens (B.L.Burtt & R.M.Sm.) R.M.Sm. was studied for its antioxidant properties. Preliminary screening of the methanol extracts of its leaves, stems, rhizomes showed that the fresh leaves had the highest antioxidant activity, with total phenolic content (TPC), ascorbic acid equivalent antioxidant capacity (AEAC), and oxygen radical absorbance capacity (ORAC) values of 1020 ± 20 mg GAE/100 g, 1130 ± 30 mg AAE/100 g, and 140 ± 30 µmol TE/g, respectively. Subsequently, a diarylheptanoid, etlingerin, was isolated from the leaf methanol extract. When contrasted with curcumin (a well-known diarylheptanoid), etlingerin showed comparable free radical scavenging properties. However, using a cell-based antioxidant assay, etlingerin showed significantly better protective effects (with cellular antioxidant activity values as high as 84 ± 4%) than curcumin at all concentrations tested. In the cytoprotective study, only etlingerin could protect cells that were challenged with hydrogen peroxide. These effects might be explained by etlingerin's high lipophilicity and good free radical scavenging properties. Etlingerin was also found to be significantly less cytotoxic than curcumin (up to 10-fold, as determined using a MTT cell viability assay), thus suggesting its safety. The work showed that etlingerin has better antioxidant properties, hence highlighting its potential as a functional food component that could reduce the risks of oxidative stress-related diseases.

The relationship between standard reduction potentials of catechins and biological activities involved in redox control

Redox homeostasis involves factors that ensure proper function of cells. The excess reactive oxygen species (ROS) leads to oxidative stress and increased risk of oxidative damage to cellular components. In contrast, upon reductive stress, insufficient ROS abundance may result in faulty cell signalling. It may be expected that dietary antioxidants, depending on their standard reduction potentials (E°), will affect both scenarios. In our study, for the first time, we systematically tested the relationship among E°, chemical properties, and biological effects in HT29 cells for a series of structurally different catechins and a major endogenous antioxidant – glutathione (GSH), at both physiological and dietary concentrations. Among chemical antioxidant activity tests, the strongest correlation with E° was seen using a DPPH assay. The values of E° were also highly correlated with cellular antioxidant activity (CAA) values determined in HT29 cells. Our results indicated that physiological concentrations (1–10 µM) of tested catechins stabilized the redox status of cells, which was not exhibited at higher concentrations. This stabilization of redox homeostasis was mirrored by constant, dose and E° independent CAA values, uninhibited growth of HT29 cells, modulation of hydrogen peroxide-induced DNA damage, as well as effects at the genomic level, where either up-regulation of three redox-related genes (ALB, CCL5, and HSPA1A) out of 84 in the array (1 µM) or no effect (10 µM) was observed for catechins. Higher catechin concentrations (over 10 µM) increased CAA values in a dose- and E°-dependent manner, caused cell growth inhibition, but surprisingly did not protect HT29 cells against reactive oxygen species (ROS)-induced DNA fragmentation. In conclusion, dose-dependent effects of dietary antioxidants and biological functions potentially modulated by them may become deregulated upon exposure to excessive doses.

Antioxidant and anti-inflammatory effects of polyphenols extracted from Ilex latifolia Thunb.

To promote the rational and effective application of Ilex latifolia Thunb., a Chinese bitter tea widely consumed as a health beverage, polyphenols were extracted from its leaves and their cellular antioxidant activity (CAA) and anti-inflammatory effect against mouse macrophage RAW 264.7 cells were analyzed. Results showed that the antioxidant capacity of polyphenols was high, and their CAA values in PBS wash and no PBS wash protocols were 6871.42 ± 85.56 and 25161.61 ± 583.55 μmol QE (quercetin equivalents)/100 g phenolic extracts, respectively. In addition, polyphenols from I. latifolia displayed strong inhibition on LPS-induced NO-production in RAW 264.7 cells. Polyphenol treatment inhibited the release of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) induced by LPS in a dose-dependent manner by ELISA and mRNA expression analysis. Western blot results showed that the anti-inflammatory activity of polyphenols from I. latifolia might be exerted through inhibiting the activation of MAPKs (ERK and JNK) and NF-κB to decrease NO, COX-2 and pro-inflammatory cytokines production. Thus, the polyphenol enriched extracts from I. latifolia are a good source of natural antioxidants with a beneficial effect against inflammation, and they may be applied as a food supplement and/or functional ingredient.

Probiotic Properties and Cellular Antioxidant Activity of Lactobacillus plantarum MA2 Isolated from Tibetan Kefir Grains.

Lactobacillus plantarum MA2 was isolated from traditional Chinese Tibetan kefir grains. Its antioxidant properties had been demonstrated in vitro and in vivo previously. In the present study, the probiotic characteristics of this strain were further evaluated by investigating its acid and bile salt tolerances, cell surface hydrophobicity, and autoaggregation, respectively. In addition, the cellular antioxidant activity (CAA) assay was applied to test the antioxidant capacity of the isolate in different growth phases. Same method was also used to evaluate the antioxidant capacity of its fermentation supernatant, cell-free extract, and intact cell quantitatively. The results of probiotic characteristic tests showed that MA2 could survive at pH2.5 and 0.3% bile salt. Meanwhile, the measurements of cell surface hydrophobicity and autoaggregation were 45.29 ± 2.15 and 6.30 ± 0.34%, respectively. The results of cellular antioxidant activity tests indicated that MA2 had high antioxidant potential. The CAA value of logarithmic phase cell-free extract of MA2 (39,450.00 ± 424.05μmol quercetin equivalents/100g sample) was significantly higher than that in stationary phase cell-free extract (3395.98 ± 126.06μmol quercetin equivalents/100g sample) and that of fermentation supernatant in logarithmic phase (2174.41 ± 224.47μmol quercetin equivalents/100g sample) (p < 0.05). The CAA method was successively applied to evaluate the antioxidant capacity of MA2 in this study, which suggests that it could be used as a useful method for lactic acid bacteria antioxidant potential evaluation.

OPTIMATION OF ENRICHMENT AND PURIFICATION OF POLYPHENOLS FROM BLUEBERRIES (VACCINIUM SPP.) BY MACROPOROUS RESINS XAD-7HP

Introduction: Blueberries are rich sources of phenolic compounds and exhibit strong antioxidant activities and a wide variety of biological activities. Methods: Polyphenols were extracted from blueberry by solvent extraction method using ethanol solution. The purification of polyphenols from blueberries (Vaccinium spp.) by macroporous resin XAD-7HP was optimized by adsorption and desorption tests. The cellular antioxidant activities of the purified polyphenols were investigated. Results: The adsorption data indicated that the process was best explained by the Langmuir isotherm model. The best conditions were determined as: blueberry polyphenols concentration, 2.00 mg/g; pH 2.0; ethanol desorption solution concentration, 70 % (v/v); flow rates for feeding and elution, 1 and 2 bed volume (BV)/h, respectively; and a water wash volume of 3 BV. Under these conditions, the purity of the blueberry polyphenols was improved from 46.3 to 86.48 %. The EC50 (concentration for 50 % of maximal effect) and CAA (cellular antioxidant activity) values of the blueberry polyphenols were 151.58 mg/mL and 6.39 µmol QE /100 g sample, respectively.Conclusion: The results demonstrate that purification of polyphenols by macroporous resins XAD-7HP will provide foundation for the development of large-scale separation of blueberry polyphenols in industry.

Effect of mash enzyme and heat treatments on the cellular antioxidant activity of black currant (Ribes nigrum), raspberry (Rubus idaeus), and blueberry (Vaccinium myrtillus) juices

ABSTRACTThe aim of this study was to determine the effect of mash enzymatic maceration and heating treatments before pressing on the antioxidant activities in selected berry juices. Total phenolic contents were determined by the Folin–Ciocalteau assay, antioxidant activities were determined by means of the oxygen radical absorbance capacity (ORAC) assay, and the intracellular antioxidant potentials were determined through the cellular antioxidant activity (CAA) assay. Blueberry juices exhibited the highest antioxidant activity, followed by black currant and raspberry juices. The mash enzyme treatment with Pectinex® Ultra Color enzyme preparation, improved the antioxidant activities in vitro. ORAC values correlated with CAA values (R2 = 0.91) and a slightly positive correlation was observed between Folin–Ciocalteau and CAA assays (R2 = 0.56). The findings support the observation that the mash enzymatic treatment of macerated fruits enhances their antioxidant activity. Considering the chemical assays (ORAC and total phenolic content), a combined treatment with heating to 85°C followed by mash enzymatic treatment was the most effective. Considering a biological model through the CAA assay, however, a comparable improvement in antioxidant activity resulted from the enzymatic and the combined treatments. Overall, the data showed that maceration enzymatic treatment improves the intracellular antioxidant activity in HepG2 human cells. To the best of our knowledge, this is the first report on the effect of the antioxidant potential of mash enzymatic and heating treatments assessed by means of a cellular approach.