Variation In Antioxidant Activity Research Articles

Biochemical and Molecular Insights into Variation in Sesame Seed Antioxidant Capability as Revealed by Metabolomics and Transcriptomics Analysis.

Sesame seeds are important resources for relieving oxidation stress-related diseases. Although a significant variation in seeds' antioxidant capability is observed, the underlying biochemical and molecular basis remains elusive. Thus, this study aimed to reveal major seed components and key molecular mechanisms that drive the variability of seeds' antioxidant activity (AOA) using a panel of 400 sesame accessions. The seeds' AOA, total flavonoid, and phenolic contents varied from 2.03 to 78.5%, 0.072 to 3.104 mg CAE/g, and 2.717 to 21.98 mg GAE/g, respectively. Analyses revealed that flavonoids and phenolic acids are the main contributors to seeds' AOA variation, irrespective of seed coat color. LC-MS-based polyphenol profiling of high (HA) and low (LA) antioxidant seeds uncovered 320 differentially accumulated phenolic compounds (DAPs), including 311 up-regulated in HA seeds. Tricin, persicoside, 5,7,4',5'-tetrahydro-3',6-dimethoxyflavone, 8-methoxyapigenin, and 6,7,8-tetrahydroxy-5-methoxyflavone were the top five up-regulated in HA. Comparative transcriptome analysis at three seed developmental stages identified 627~2357 DEGs and unveiled that differential regulation of flavonoid biosynthesis, phenylpropanoid biosynthesis, and stilbene biosynthesis were the key underlying mechanisms of seed antioxidant capacity variation. Major differentially regulated phenylpropanoid structural genes and transcription factors were identified. SINPZ0000571 (MYB), SINPZ0401118 (NAC), and SINPZ0500871 (C3H) were the most highly induced TFs in HA. Our findings may enhance quality breeding.

Oxidative Stress in Postbariatric Patients: A Systematic Literature Review Exploring the Long-term Effects of Bariatric Surgery.

The present study investigates the impact of oxidative stress after bariatric surgery in patients with obesity. This field of study has gained great interest in recent years due to the role that oxidative stress plays in metabolic diseases. Obesity, by itself, can generate an increase in reactive oxygen and nitrogen species, intensifying cellular damage and promoting the progression of adverse metabolic conditions. In this context, bariatric surgery emerges as a candidate capable of modifying oxidative stress biomarkers, facilitating the patient's metabolic recovery. A systematic review was carried out, identifying 30 studies found in databases such as PubMed, Scopus, Web of Science, and Google Scholar. It looked at the link between oxidative stress and recovery after bariatric surgery in patients. The selection of studies was based on the measurement of oxidative stress biomarkers before and after surgical intervention. The results reveal a significant decrease in oxidative stress biomarkers after bariatric surgery. However, a notable variability in antioxidant activity is observed between different patients, as well as a significant influence of comorbidities. Bariatric surgery is postulated as an effective intervention in reducing oxidative stress in patients with obesity, enhancing antioxidant activity and improving patient recovery. This finding highlights the importance of considering oxidative stress management as an integral part of postoperative care, suggesting the need to implement complementary treatment strategies to optimize health outcomes.

Profiling of Essential Oils from the Leaves of Pistacia lentiscus Collected in the Algerian Region of Tizi-Ouzou: Evidence of Chemical Variations Associated with Climatic Contrasts between Littoral and Mountain Samples.

Leaves of Pistacia lentiscus were collected from two Algerian sites in the mountains and the littoral of the Tizi-Ouzou region. The harvest was conducted in four consecutive seasons on the same selected set of trees. Essential oils (EOs) were extracted by hydrodistillation; then, they were analyzed by gas chromatography coupled mass spectrometry (GC-MS). Forty-seven constituents could be detected and quantified, including α-pinene (2–13%), β-caryophyllene (8–25%), β-myrcene (0.3–19%), bornyl acetate (0.8–7%), δ-cadinene (3–8%), bisabolol (1–9%), β-pinene (0.9–7%), caryophyllene oxide (4–9%), and α-cadinol (3–11%). Antioxidant (AOx) activities of the EOs were assessed by ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2′-azino-bis (3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) assays. Significant differences in EO composition and AOx activities appeared dependent on the season and the site. Variations of AOx activities were significant for the FRAP and ABTS tests but not for DPPH. Characterization of the leaf fatty acyl (FA) profiles was performed by GC-MS. Variability appeared according to season and altitude. Polyunsaturated fatty acids levels were high (27–55%) at the coldest date and place. The levels of linolenic acyl in the leaves were significantly correlated with bisabolol levels in the EOs (Spearman’s correlation coefficient: 0.818). Such results will be useful for the sustainable local valorization of wild P. lentiscus. These data also open new routes for further studies on terpenoid biosynthesis using correlation networks and fluxomic approaches.

Assessing phenolic content and antioxidant potential diversity in Allium plants using multivariate data analysis

The genus Allium includes hundreds of plant species and is regarded as one of the most cultivated vegetables. It is an important source of novel therapeutic compounds known for their beneficial effects on human health; however, there could be differences in content, composition, type, and bioactivity of the phytochemicals found among the Allium plants. The main purpose of this study was to acquire insights on the variation in antioxidant profiles and phenolic content between Allium accessions in different species, as well as between similar species of several varieties. We collected 112 accessions from more than 20 countries, and grew them under similar agronomic conditions. The antioxidant potential was evaluated by using 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS), 1,1-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and reducing power (RP) assays. The total phenolic content (TPC) was studied using the Folin–Ciocalteu method. TPC varied from 3.43 (accession 199897) to 22.19 (accession 273483) µg gallic acid equivalent/mg dry weight (DW) of the aerial organs of Allium. The antioxidant activity of Allium samples ranged from 4.37 (accession 806595) to 57.46 (accession number 711971) µg Trolox equivalent/mg DW; 0.35 (accession 117246) to 9.53 (accession 711971) µg ascorbic acid equivalents/mg DW; 2.92 (accession 199890) to 21.20 (accession 803493) µgAAE/mg DW; and 0.80 (accession 117260) to 31.13 (accession 803527) µgAAE/mg DW using ABTS, DPPH, FRAP, and RP assays, respectively. Accessions 273483 (A. cepa), 283346 (A. cepa ‘cepa’), and 803527 (unknown species) had the highest TPC, FRAP, and RP values among those tested, while the highest ABTS and DPPH radical scavenging activities were recorded in accession 711971 (A. ramosum). Pearson’s coefficient of correlations indicated that variables (TPC, ABTS, DPPH, FRAP, and RP values) correlated significantly each other, with r-values between 0.585 and 0.894. Principal component analysis plots and hierarchical cluster analysis indicated significant variability in antioxidant activity and phenolic content among all the accessions studied, as well as within similar species. Based on our results from principal component and hierarchical cluster analysis, accession 283346 (A. cepa ‘cepa’), K139348 (A. fistulosum), and 711971 (A. ramosum) are potential sources of phenolics and natural antioxidants. The variability in total phenolic and antioxidant activity among the Allium accessions can be used by breeders, food technologists, nutritionist, and researchers for assessing breeding lines for genetic selection and for monitoring levels of these factors during food storage and processing.

Composition of essential oil of Ocimum basilicum L., minimum and variability in antioxidant activity of essential oil of leaves and flowering tops of Ocimum basilicum L. Genovese following seasons of culture under arid climate (southeast of Algeria)

Composition of essential oil of Ocimum basilicum L., minimum and variability in antioxidant activity of essential oil of leaves and flowering tops of Ocimum basilicum L. Genovese following seasons of culture under arid climate (southeast of Algeria)

Year-to-year Variations in Antioxidant Components of High-Lycopene Tomato (Solanum lycopersicum L.) Breeding Lines

A two-year field study (2013−2014) was performed to evaluate phytochemical content and antioxidant activity of two high-lycopene tomato breeding lines (HLT-F71 and HLT-F72) grown under open field conditions as compared to the traditional cultivar (cv) Rio Grande. Two open-field trials were conducted in 2013 and 2014. Three tomato cvs were used: two high-lycopene tomato advanced breeding lines (HLT-F71 and ‘HLT-F72’) (F7 generation), and the open-pollinated cv Rio Grande commonly grown in Tunisia. Regardless the growing years and cvs, lycopene content ranged from 98.8 to 280.0 mg/kg fw, total phenolics from 176.1 to 831.8 mg GAE/kg fw flavonoids from 169.7 to 552.1 mg RE/kg fw and total vitamin C from 183.4 to 370.0 mg/kg fw. Significant year-to-year variability was only detected in total phenolics and flavonoid content. No significant year-to-year variability in antioxidant activity was detected in high-lycopene lines. Disregarding the cv, tomato berries harvested on July 2014 had 143% - 224% higher total phenolics and 8% to 47% higher flavonoid contents compared to tomato berries harvested on July 2013. However, disregarding the cv, tomato berries harvested on July 2013 had 6% -17% higher lycopene and 8% -21% higher LAA compared to berries harvested on 2014. During the second growing year, the higher temperature, particularly prior to harvest, determined a decrease in lycopene content and a significant increase in total phenolics regardless the cv. Although the huge variability in total phenolics and the decrease in lycopene content during the second harvest, the antioxidant activity was not affected by year-to-year variability. This reveals consistent functional quality of these cvs and minimal genotype*environmental conditions interaction.

Roles of the glutathione- and thioredoxin-dependent systems in the Escherichia coli responses to ciprofloxacin and ampicillin.

Recently, it was proposed that some antibiotics stimulate the production of reactive oxygen species (ROS), which contribute to cell death. Later, other research groups have provided arguments against ROS-mediated killing of bacteria by antibiotics. At present, there remain a number of unanswered questions in understanding of the role of ROS in killing by antibiotics. Mutants of Escherichia coli in components of the thioredoxin and glutaredoxin redox pathways used in this study possess a great variability in antioxidant activity, and they therefore are a useful model for the investigation of the role of oxidative stress in bactericidal effect of antibiotics. Statistical analysis did not reveal a significant correlation between the susceptibility of the mutants to ciprofloxacin and ampicillin and their resistance to peroxide stress. However, we found strong reverse correlations between the bactericidal activity of antibiotics and the specific growth rate of these mutants at the moment of drug addition. Supplements changing the level of intra- and extracellular glutathione considerably affected E. coli susceptibility to ciprofloxacin and ampicillin. The effect of GSH precursors on bactericidal activity of antibiotics was also observed in gshA mutants.

Synthesis and SAR Study of Antioxidant Potential of Polyhydroxy Coumarin Derivatives

A series of polyhydroxycoumarin derivatives, that are analogs of naturally occurring compounds, have been synthesized and their antioxidant activity (AOA) examined using DPPH, ABTS, and in vitro lipid peroxidation inhibition assays. The SAR for differently substituted polyhydroxycoumarins is reported by evaluating the positional effect of hydroxyl groups and the effect of incorporation of the lipophilic group on antioxidant activity. Many of the compounds synthesized have 4-5 fold higher AOA than ‘Trolox’ taken as standard. In DPPH and ABTS assays, the trihydroxycoumarins were observed to have a potent antioxidant activity. It has been observed that alkylation at C-3/C-4 position as well as the incorporation of pyran ring on coumarin skeleton led to the reduction in AOA in the above two assays. However, in lipid peroxidation inhibition assay an enhancement in AOA was observed for such modifications. The rationale for the observance of variation in AOA in different assays is also studied.

Agro-ecological region based variations in the antioxidant activity of tamarind (Tamarindus indicaL.) fruit pulp

Tamarind (Tamarindus indica L.) is a tropical seasonal bearing fruit species grown in relatively dry regions in the tropics. Its sweet and aromatic fruit pulp contains polyphenols, influenced by regional and seasonal factors. Therefore this research investigated the variability of antioxidant activity (AOA) and total phenolic content (TPC) of tamarind fruit grown in six different-ecologically dissimilar growing regions. Ethanolic extracts of tamarind fruit pulp were prepared for analysis. Total phenolic content of the tested tamarind samples ranged within 0.77-5.85 mg GAE g-1 fresh weight (FW). Tamarind fruits collected from agro-ecological zone, DL3 (dry and warm region) had the highest TPC, followed by the fruits from IL1 (moderately dry and warm region) (5.39±1.8 mg GAE g-1 [FW]). Antioxidant activity of fruit pulp from relatively drier (low rainfall) regions, IL1 (70.17±9.9 mmol g-1 [FW]) and DL3 (69.18±7.2 mmol g-1 [FW]) were much higher than the other regions. The lowest AOA was found in the fruit samples from DL4 (30.7±1.1 mmol g-1 [FW]) which is geographically distant to DL3 and IL1. Positive correlations could be established between AOA and TPC contents (r=0.92) of the tamarind fruit pulp. Hence the influence of agro-ecological region based environmental conditions on the AOA and its major contributors, polyphenols in tamarind fruit pulp could be established.

Application of principal component and hierarchical cluster analysis to classify different spices based on in vitro antioxidant activity and individual polyphenolic antioxidant compounds

This study investigated the variations in antioxidant profiles between spices using pattern recognition tools; classification was achieved based on the results of global antioxidant activity assays (2,2-diphenyl-1-picrylhydrazyl [DPPH], oxygen radical absorbance capacity [ORAC], ferric reducing antioxidant power [FRAP], microsomal lipid peroxidation [MLP] and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) [ABTS]), levels of different polyphenolic compounds (gallic acid [GA], carnosol [CAR], carnosic acid [CRA], caffeic acid [CA], rosmarinic acid [RA], luteolin-7- O-glucoside [LOG], apigenin-7- O-glucoside [APOG] and total phenols [TP]) of spices namely rosemary, oregano, marjoram, sage, basil, thyme, fennel, celery, cumin and parsley, commonly consumed in Ireland were analyzed. Rosemary showed the highest antioxidant activity measured by the DPPH (11.02 g Trolox/g DW) assay, whereas oregano had the highest activity in the ORAC (28.31 g Trolox/g DW) test. By contrast, parsley showed the lowest antioxidant activity in both of the assays. Interrelationships of these assays and the spices were investigated by principal component analysis (PCA) and hierarchical cluster analysis (HCA). PCA revealed that the first two components represented 73% of the total variability in antioxidant activity and different antioxidant groups. HCA classified samples into four main groups on the basis of the measured parameters.

Application of principal component and hierarchical cluster analysis to classify fruits and vegetables commonly consumed in Ireland based on in vitro antioxidant activity

The purpose of this study was to gain insights into the variations in antioxidant profiles between fruits and vegetables using pattern recognition tools; classification was achieved based on global antioxidant activity, levels of antioxidant groups (total phenolics, total anthocyanins, ascorbic acid) and quality parameters (instrumental colour, moisture). Six vegetables (broccoli, carrot [organic and intensively grown], butterhead lettuce, red onion, yellow onion) and eight fruits (blueberries, cherry tomato, cranberries, red grapes, green pepper, raspberry, red pepper and strawberry) commonly consumed in Ireland were analysed. Antioxidant activity (ARP) and concentrations of bioactive compound groups differed according to sample type. Berry fruits had the highest antioxidant activity (1.51–2.97 (g/L) −1). By contrast, vegetables were quite low in antioxidant activity (0.14–0.39 (g/L) −1). Interrelationships between the parameters analysed and the different fruits and vegetables were investigated by principal component analysis (PCA) and hierarchical cluster analysis (HCA). PCA revealed that the first two components represented 62% of the total variability in antioxidant activity and different antioxidant groups. HCA classified samples into four main groups on the basis of the measured parameters.

Variation and Heritability Estimates of Anthocyanins and Their Relationship to Antioxidant Activity in a Red Raspberry Factorial Mating Design

We determined variance components and narrow-sense heritability estimates for total and individual anthocyanin (ACY) content and antioxidant activity (AA) in fruit from 411 genotypes in a red raspberry (Rubus idaeus L.) factorial mating design based on 42 full-sib families derived from seven female and six male parents, harvested in 2002 and 2003. Within half-sib family total ACY content ranged from ≈1-60+ mg/100 g fruit in both seasons. The four major ACYs quantified by high-performance liquid chromatography also showed wide ranges each year. Female and male parent contributions to variation in total and individual ACYs were significant (P ≤ 0.001) in combined year analysis, and together accounted for 29% to 48% of the total variation. A substantial proportion of the female contribution was attributed to the use of a pigment-deficient R. parvifolius L. × R. idaeus hybrid derivative as a female parent. Female × male interaction was nonsignificant and contributed negligibly to total variance. Year effects accounted for <2.5% of variation in ACYs and were only marginally significant. Year interactions were negligible. Within family variation (among plots and within plot) accounted for ≈50% of the variation in total ACY and 62% to 69% of the variation in individual ACYs. Combined year narrow-sense heritability estimates were high (h2 = 0.54-0.90 for individual ACYs, 1.00 for total ACY) among all factorial genotypes, but moderate when the progeny of the R. parvifolius derivative were excluded (h2 = 0.45-0.78 for individual ACYs, 0.74 for total ACY). The latter estimates are applicable to breeding programs in which pigment-deficient genotypes are rarely or never used in breeding. Parental main effects were significant for AA, together accounting for 19% of total variance; female × male interaction was nonsignificant. Year effects were marginally significant and year interactions nonsignificant; together these sources of variation contributed <2% of total variation in AA. The majority of AA variation was found within- and among-plots within family. The phenotypic correlation between AA and total ACY was r = 0.53, and ranged from r = 0.21-0.46 between AA and individual ACYs; genetic correlations between AA and the ACYs were similar to the phenotypic correlations, suggesting predominantly additive genetic effects accounted for the phenotypic correlations. Linear modelling for AA based on individual ACYs and their interactions explained ≈0.53 of AA variation, substantially less than that explained by total phenolic content (R2 = 0.88). Our results show substantial variation and moderate to high narrow-sense heritability estimates for red raspberry ACYs, but ACY content and profile information are ineffective proxies and predictors for AA in red raspberry fruit.

Genotypic and Environmental Variation in Antioxidant Activity and Total Phenolic Content among Blackberry and Hybridberry Cultivars

Antioxidant compounds absorbed from our diet are thought to have a role in preventing chronic diseases that result from oxidative damage. Berry fruit have high levels of antioxidants, and further increases in antioxidant activity (AA) might be possible through breeding. We determined the AA, total phenolic content (TPH), and fruit weight in 16 blackberry and hybridberry (Rubus L.) cultivars harvested in New Zealand and Oregon in 2002 and 2003, to assess genetic and environmental variation. Both AA and TPH varied significantly between years within location, but not among cultivars or between locations per se. However, cultivar interactions with both location and year within location contributed to variation in both variates. In contrast, both cultivar and location contributed to variation in fruit weight, but years within location did not. However, the cultivar × year within location interaction was significant for this trait. Variance component distributions confirmed that cultivar and location effects together contributed little (<20%) to the total variation in either AA or TPH, while cultivar × environment interactions accounted for >50% of total variation in these traits. Cultivar and location effects together contributed ≈70% of the total variation observed in fruit weight. Phenotypic correlations were significant between AA and fruit weight (r = -0.44), and between TPH and fruit weight (r = -0.51). When adjusted for fruit weight, analyses for AA and TPH demonstrated that cultivar effects approached significance (P = 0.06) and accounted for ≈25% of total variance, while location effects accounted for none. Although the cultivars in this study had diverse interspecific backgrounds, utilization of various Rubus species in blackberry and hybridberry breeding is not uncommon, and our results demonstrating significant cultivar × environment interaction for AA and TPH should be applicable to breeding for high AA genotypes.

VARIABILITY FOR ANTIOXIDANT ACTIVITY IN THE U.S. COWPEA [Vigna unguiculata (L) WALP.] CORE COLLECTION

Antioxidants are important to human health, as they are responsible for reduced risk of diseases such as cancer, hence motivating researchers to examine crop plants for available antioxidant compounds. There is also increasing interest in the use of antioxidants from plants instead of synthetic products. In order to evaluate variability of antioxidant activity (AOA) in cowpea, 697 cowpea accessions from the U.S. Cowpea Core Collection obtained from the Regional Plant Introduction Station, Griffin, Ga., were analyzed for AOA expressed as μg trolox equivalents/gdw. Two grams of dry seed from each accession were ground, extracted in methanol and analyzed for AOA using the free radical, 2,2-Diphenyl-1-picrylhydrazyl (DPPH), method. A large variation in AOA within the core collection, ranging from 1859 μg·g–1 dw (PI 180355, pigmented seed coat) to 42.6 μg·g–1 dw (PI 583100, cream seed coat), was observed. A least significant difference of 131.5 (p =0.05) was obtained. Higher AOA was manifested by accessions with pigmented seed coats. Accessions that were speckled, striped or had a pigmented eye were moderate in AOA, while the cream types were generally low. Variability in AOA observed among cowpea accessions suggests that breeding for high AOA can be successfully conducted. Accessions with high AOA could also be used to extract antioxidants for industrial purposes. Some accessions were a mixture of various colors and patterns, making it difficult to classify them into a particular category. Therefore, there is need to ensure purity of these accessions by ascertaining whether the mixtures are physical, i.e., combination of different varieties, or are composed of segregating material.

Variation and Heritabilities of Antioxidant Activity and Total Phenolic Content Estimated from a Red Raspberry Factorial Experiment

Variance components and narrow-sense heritabilities were estimated for antioxidant activity (AA), total phenolic content (TPH), and fruit weight in red raspberry (Rubus idaeus L.) fruit from offspring of a factorial mating design. Forty-two full-sib families utilizing seven female and six male parents were evaluated in each of two years in Motueka, New Zealand. In a single year, values within individual half-sib families ranged as widely as 25.3-79.4 μg·g-1 fruit for AA, 205-597 mg/100 g fruit for TPH, and 1.06-7.69 g for fruit weight. Analyses of variance for these three variates demonstrated significant parental source variation in both individual and combined year analyses. For AA and TPH, female parental effects accounted for ≈7% to 19% of total variation, while male effects accounted for ≈6% to 8%. A partially pigment deficient R. parvifolius L. derivative female parent accounted for some of these differences. Female × male parent interaction was not significant for AA and TPH and was marginally significant for fruit weight in combined year analysis. Year had a significant effect on the overall mean AA and TPH, but contributed less than genetic effects to the overall variation in all three traits. Interactions of year with genetic effects were not statistically significant for AA or TPH, indicating that between-year rank or scale changes among families were negligible. The largest proportion of variation was found within rather than among full-sib families. However, variation among plots within full-sib families accounted for 12% to 19% of total variation, indicating environmental differences accounted for some of the observed within-family variation in AA and TPH. Antioxidant activity and TPH were highly phenotypically correlated (r = 0.93); their genetic correlation (r = 0.59) implies that substantial additive genetic factors underlie the phenotypic correlation, but that nonadditive genetic or environmental influences are also important. Both AA and TPH were weakly negatively phenotypically correlated with fruit weight (r = -0.34 and -0.33, respectively), but the corresponding genetic correlations were close to zero. Thus, selection for both high AA or TPH and high fruit weight is possible. Narrow-sense heritability estimates based on variance components from combined year data were h2 = 0.54, 0.48, and 0.77 for AA, TPH, and fruit weight, respectively. These estimates imply a rapid response to selection is possible.

Correlation between polymorphic variants of the genes for transferrin and angiotensin-converting enzyme and antioxidant activity of blood plasma

In 75 male and 46 female subjects of an urban population (93% Russians) and in 38 males and 40 females of a rural population (87% Russians), the antioxidant activity (AOA) of blood plasma was determined from the plasma ability to reduce the yield of products interacting with thiobarbituric acid in the model lecithin-Fe2+ ion system. In the urban population, the loci TF (AvaI in exon5) and ACE (I/D polymorphism of the Alu repeat in intron16) were studied in 130 and 141 subjects, respectively. Of them, 102 and 111 subjects, respectively, were examined for AOA. In the rural population, the corresponding sample sizes were 75 and 76 (73 and 74 subjects were examined for AOA). The polymorphic loci of the urban and rural populations did not differ in the allele frequencies. In both populations Hardy--Weinberg and gametic equilibria were observed. The contributions of the TF and ACE genes to AOA variation in the combined sample from the urban and rural populations were 0.6 and 0.5%, respectively.

Genetic variability antioxidant activity of blood plasma in urban population (Seversk) of Tomsk region

Antioxidant activity (AOA) was measured in 185 inhabitants of the town of Seversk (members of 43 families and unrelated individuals). AOA was defined on the ability of a blood plasma to reduce an output of products, reacting with thiobarbituric acid in the model system «lecithine-Fe2 +-ions». Polymorphism of gastrointestinal glutathione peroxidase (GPX2) gene (two-allelic dinucleotide (TC)n repeat polymorphism) was investigated in 208 individuals. The presence of seasonal changes was revealed and no influences of sex and age on AOA in the considered group were shown. Approximately 50% variance in total AOA was due to the additive effects of genes. No statistical significant association between genetic variability of GPX2 and AOA variation was revealed. Estimation of GPX2 genetic variability contribution to AOA level was 2.53%.

Variability in Antioxidant Activity in Blueberry and Correlations among Different Antioxidant Activity Assays

Variation in antioxidant activity (AA), total phenolic content (TPH), and total anthocyanin content (ACY) was examined in 1998 and 1999 in fruit of 52 (49 blue-fruited and 3 pink-fruited) genotypes from a blueberry breeding population. The species ancestry included Vaccinium corymbosum L. (northern highbush blueberry), V. angustifolium Ait. (lowbush blueberry), V. constablaei Gray (mountain highbush blueberry), V. ashei Reade (rabbiteye blueberry), and V. myrtilloides Michx. (lowbush blueberry). Using a methyl linoleate oxidation assay (MeLO) on acidified methanolic extracts of the berries, a 5-fold variation was found in AA in 1998 and a 3-fold variation in 1999 among the blue-fruited genotypes. Analyses of variance (ANOVA) revealed variation among genotypes (P < 0.0001) in single and combined years, regardless of inclusion of pink-fruited selections and adjustment for berry size. While mean AA of all genotypes did not change between the 2 years, ranking of some genotypes for AA changed significantly between 1998 and 1999. Of the 10 genotypes that demonstrated the highest AA in 1998, four were among the 10 genotypes that demonstrated highest AA in 1999. Similarly, of the 15 genotypes with the highest AA, 10 were the same both years. As with AA, mean TPH of all genotypes did not change between years and ANOVA demonstrated genotypic variation regardless of adjustment for berry size/weight or exclusion of pink-fruited selections. Changes in genotype rank occurred between years. The difference in TPH between lowest- and highest-ranking blue-fruited genotypes was ≈2.6-fold in both 1998 and 1999. Seven of the 10 highest-ranking genotypes were the same both years and TPH correlated with AA (r = 0.92, P < 0.01) on a genotype mean basis for combined years. ACY correlated less well with AA (r = 0.73, P < 0.01 for combined years). When genotypes were categorized into six groups according to species ancestry, V. myrtilloides and V. constablaei × V. ashei crosses ranked highest and second highest, respectively, for AA in both years. The groups comprised of V. corymbosum genotypes, V. angustifolium genotypes, and those with both V. corymbosum and V. angustifolium in their lineage were indistinguishable from each other. Samples from some of the genotypes were analyzed for oxygen radical absorbance capacity and ferric-reducing antioxidant power, and these aqueous-based antioxidant assays correlated well with the lipid emulsion-based MeLO (all r ≥ 0.90, P < 0.01). The three antioxidant assays may be equally useful for screening in a blueberry breeding program and the choice of assay may depend on the goal of the program and the resources available.