摘要 :
Muskmelon (Cucumis melo L.) is a popular summer fruit consumed all over the world due to the combination of refreshingly sweet taste, pleasant flavour and nutritional value. Melon fruit is characterized by germplasm variability wi...
展开
Muskmelon (Cucumis melo L.) is a popular summer fruit consumed all over the world due to the combination of refreshingly sweet taste, pleasant flavour and nutritional value. Melon fruit is characterized by germplasm variability with superior quality.This study aimed to evaluate 5 promising local muskmelon cultivars (Maazoun, Galaoui, Stambouli, Trabelsi, Asli) for some physicochemical characteristics, the content of different bioactive compounds and the antioxidant activity. The experiments were conducted for two consecutive years 2018 and 2019 at the support station of the inter-professional vegetable group positioned in the North East of Tunisia. Significant differences were observed across the melon cultivars (P<0.05) for soluble solids (9-12°Brix),/iH (5.5-6.6), carotenoid (7.5-59.5 mg/ kgFW), phenolic (400-1390 mg GAE/kgFW), flavonoid (251.3-390 mg RE/kgFW), vitamin C (138.2-193 mg/kg FW) contents, as well as hydrophilic (102.28-285.43 pMTrolox/lOOgFW) and lipophilic (30-180.22 pMTrolox/100g FW) antioxidant activities. Galaoui showed the highest levels of carotenoids, phenolics, flavonoids, vitamin C and antioxidant activities followed by Stambouli. Trabelsi cultivar also had a high level of flavonoids. The enhanced hydrophilic antioxidantactivity in Galaoui was significantly conelated to phenolic content (r = 0.91). These findings proved that besides being refreshing summer fruit, muskmelon can be considered a promising healthy produce with a superior potential source of natural antioxidants.
收起
摘要 :
Antioxidant properties of individual essential oils from lemon (Citrus limon L.), pink grapefruit (Citrus paradisi L.), coriander (Coriandrum sativum L.), and clove (Caryophyllus aromaticus L.) buds and their mixtures were studied...
展开
Antioxidant properties of individual essential oils from lemon (Citrus limon L.), pink grapefruit (Citrus paradisi L.), coriander (Coriandrum sativum L.), and clove (Caryophyllus aromaticus L.) buds and their mixtures were studied by capillary gas-liquid chromatography. Antioxidant activity was assessed by oxidation of the aliphatic aldehyde hexanal to the carboxylic acid. The lowest and highest antioxidant activities were exhibited by grapefruit and clove bud essential oils, respectively. Mixtures containing clove bud essential oil also strongly inhibited oxidation of hexanal. Changes in the composition of essential oils and their mixtures in the course of long-term storage in the light were studied. The stability of components of lemon and coriander essential oils in mixtures increased compared to individual essential oils.
收起
摘要 :
Ten genotypes of red-fleshed watermelon [Citrullus lantus (Thunb.)] were estimated for various health promoting bioactive compounds. The evaluated genotypes showed wide variability in total phenols, total flavonoids, tannin, total...
展开
Ten genotypes of red-fleshed watermelon [Citrullus lantus (Thunb.)] were estimated for various health promoting bioactive compounds. The evaluated genotypes showed wide variability in total phenols, total flavonoids, tannin, total carotenoids and lycopene contents. The antioxidant activity was estimated by using in vitro assay of cupric reducing antioxidant capacity (CUPRAC). The significant difference (P=0.05) was observed among evaluated watermelon genotypes for different phytochemicals and antioxidants. The total phenols varied from 16.77 to 21.41 mg/g, total flavoniods 55.60 to 100.93 mg/100g and tannin content 35.07 to 60.83 mg/100g on dry weight basis. Total carotenoids and lycopene ranged from 4.90 to 8.06 mg/100g and 3.74 to 6.80 mg/100g, respectively on fresh weight basis. The average antioxidant activity was found to be varied from 40.13 to 84.05 mu mol TE/100g fresh weight. The results indicate that red-fleshed genotypes of watermelon are good source of antioxidants and showed significant variability for different phytochemicals and antioxidants that could be exploited to develop new cultivars/hybrids of superior quality for nutritional security.
收起
摘要 :
The consumption of fruits and vegetables with high antioxidant activities leads to best healthful results. Therefore, in the present investigation we tried to find the peak of the kiwifruits antioxidant activity during the first 1...
展开
The consumption of fruits and vegetables with high antioxidant activities leads to best healthful results. Therefore, in the present investigation we tried to find the peak of the kiwifruits antioxidant activity during the first 10 days of ethylene treatment (100 ppm at 20 °C). In order to receive the most reliable data five different antioxidant assays were used: ferric-reducing/antioxidant power (FRAP); cupric reducing antioxidant capacity (CUPRAC); trolox equivalent antioxidant capacity (TEAC); 1, 1-diphenyl-2-picrylhydrazyl radical (DPPH); and Folin-Ciocalteau. It was found by all applied methods that kiwifruit samples have the highest contents of polyphenols and flavonoids and the highest antioxidant activity on the 6-th day of the ethylene treatment. The correlation coefficients between polyphenols, flavonoids and antioxidant activities of kiwifruit methanol extracts with TEAC and CUPRAC, were as followed: 0.81 and 0.63, and 0.23 and 0.17, respectively, and showed that the free polyphenols correlation coefficients were higher than that of the flavonoids. In conclusion: during ethylene treatment the bioactivity of kiwifruit is increasing and reaches its maximum at the 6th day and therefore it is the optimum time for kiwifruit consumption; total polyphenols were the main contributor to the overall antioxidant activity of kiwifruit; the most sensitive test for antioxidant activities determination is FRAP.
收起
摘要 :
Fifty phenolic antioxidants (AH) (42 individual compounds and 8 binary mixtures of two antioxidants) were chosen for a comparative analysis of their radical-scavenging (H-donating) and chain-breaking (antioxidant) activity. Correl...
展开
Fifty phenolic antioxidants (AH) (42 individual compounds and 8 binary mixtures of two antioxidants) were chosen for a comparative analysis of their radical-scavenging (H-donating) and chain-breaking (antioxidant) activity. Correlations between experimental (antiradical and antioxidant) and predictable (theoretical) activities of 15 flavonoids, 15 hydroxy cinnamic acid derivatives., 5 hydroxy chalcones, 4 dihydroxy coumarins and 3 standard antioxidants (butylated hydroxytoluene, hydroquinone, DL-α-tocopherol) were summarized and discussed. The following models were applied to explain the structure-activity relationships of phenolic antioxidants of natural origin: (a) model 1, a DPPH assay used for the determination of the radical-scavenging capacity (AH + DPPH·-> A· + DPPH-H); (b) model 2, chem-iluminescence of a model substrate RH (cumene or diphenylmethane) used for the determination of the rate constant of a reaction with model peroxyl radicals (AH + RO2·-> ROOH + A·); (c) model 3, lipid autoxidation used for the determination of the chain-breaking antioxidant efficiency and reactivity (AH + LO2·-> LOOH + A·; A· + LH (+O2)->AH + LO2·); and (d) model 4, theoretical methods used for predicting the activity (predictable activity). The highest lipid oxidation stability was found for antioxidants with a catecholic structure and for their binary mixtures with DL-α-tocopherol, as a result of synergism between them.
收起
摘要 :
The measurement of antioxidant activity using biologically relevant assays is important to screen fruits, vegetables, natural products, and dietary supplements for potential health benefits. The cellular antioxidant activity (CAA)...
展开
The measurement of antioxidant activity using biologically relevant assays is important to screen fruits, vegetables, natural products, and dietary supplements for potential health benefits. The cellular antioxidant activity (CAA) assay quantifies antioxidant activity using a cell culture model and was developed to meet the need for a more biologically representative method than the popular chemistry antioxidant capacity measures. The objective of the study was to determine the CAA, total phenolic contents, and oxygen radical absorbance capacity (ORAC) values of 27 vegetables commonly consumed in the United States. Beets, broccoli, and red pepper had the highest CAA values, whereas cucumber had the lowest. CAA values were significantly correlated to total phenolic content. Potatoes were found to be the largest contributors of vegetable phenolics and CAA to the American diet. Increased fruit and vegetable consumption is an effective strategy to increase antioxidant intake and decrease oxidative stress and may lead to reduced risk of developing chronic diseases, such as cancer and cardiovascular disease.
收起
摘要 :
Antioxidant properties of mushroom extracts sequentially isolated by cyclohexane, dichloromethane, methanol, and water from Phaeolus schweinitzii, Inonotus hispidus, Tricholoma columbetta, Tricholoma caligatum, Xerocomus chrysente...
展开
Antioxidant properties of mushroom extracts sequentially isolated by cyclohexane, dichloromethane, methanol, and water from Phaeolus schweinitzii, Inonotus hispidus, Tricholoma columbetta, Tricholoma caligatum, Xerocomus chrysenteron, Hydnellum ferrugineum, Agaricus bisporus and Pleurotus ostreatus were evaluated by DPPH center dot, ABTS(center dot+) scavenging capacity, ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), and Folin-Ciocalteu total phenolic content (TPC) methods. The integrated values ('antioxidant scores') for evaluating antioxidant potential of extracts and dry mushroom substances are proposed. Antimicrobial activity was screened against Gram-positive (Bacillus cereus), Gram-negative (Pseudomonas aeruginosa) bacteria and fungi (Candida albicans) by agar diffusion method. The highest antioxidant capacity values (in mu M TE/g extract dw) were found for methanol fractions of P. schweinitzii (9.62 +/- 0.03 in DPPH center dot; 109 +/- 3 in FRAP; 164 +/- 1 in ABTS(center dot+); 340 +/- 3 in ORAC assays) and I. hispidus (9.5 +/- 0.04 in DPPH center dot; 54.27 +/- 0.46 in ABTS(center dot+); 88.31 +/- 1.96 in FRAP; 290 +/- 1 in ORAC assays). Extracts of other species possessed considerably lower antioxidant activities. The extracts of I. hispidus were more effective against tested microbial species than other mushrooms. In conclusion, our results show that some wild mushrooms might be promising dietary sources of natural antioxidants and antimicrobial agents. (C) 2014 Elsevier Ltd. All rights reserved.
收起
摘要 :
Macromolecular antioxidant (MA) fractions and their antioxidant and antimicrobial activities are largely ignored from most conventional extractive processes compared to the well-known extractable polyphenol fractions. This study i...
展开
Macromolecular antioxidant (MA) fractions and their antioxidant and antimicrobial activities are largely ignored from most conventional extractive processes compared to the well-known extractable polyphenol fractions. This study investigated subtropical spineless cladode MA extracts in comparison with their extractable fractions; as well as the effect of freeze and oven drying methods on extract yields and bioactivities. Cladode extractable phenol (EP) and MA fractions antioxidant capacities, antimicrobial potential against multi-drug resistant bacterial cultures, and phenolic content were evaluated. LC/MS was used to analyse/profile extract components. Freezedried samples from all the extracts showed better antioxidant and antimicrobial activities than the oven-dried samples. Antibacterial and antioxidant activities were generally higher in hydrolysed (MA) than in unhydrolysed (extractable) fractions. DPPH radical scavenging activity (RSA) EC50 values correlated with phenol contents (R-2 = 0.9609). LC/MS extract profiles showed the presence of phenolic acids, flavonoid derivatives and other unidentified compounds. Isovitexin 7-O-xyloside-2 ''-O-glucoside, polyhydroxypregnane glycoside and neohancoside C were identified for the first time in Opuntia cladode extracts. This study showed that cladode EP and MA extracts have potential as rich antioxidant sources and can be key to the discovery of new antimicrobials. (C) 2019 SAAB. Published by Elsevier B.V. All rights reserved.
收起
摘要 :
The phenolic content, antioxidant activity and toxicity of three varieties of extracts of rizga flour on white albino male rats was evaluated. The antioxidant activities of the extracts as determined by the quantities of phenols p...
展开
The phenolic content, antioxidant activity and toxicity of three varieties of extracts of rizga flour on white albino male rats was evaluated. The antioxidant activities of the extracts as determined by the quantities of phenols present and scavenging activities on 2,2-Diphenyl-l-picrylhydrazyl (DPPH) radical indicated that all three varieties of rizga flour contained significant quantities of antioxidants and phenols. However, the total antioxidant capacity and polyphenolic contents of langaat was lower than that of beebot and riyom (p<0.05) with an IC50 of 90.16 jag mLr1 for langaat, 30.28 jxg mLr1 for beebot and 60.27 ju.g mLr1 for riyom as compared with the standard (Quercetin) that had an IC50 of 23.17 jxg mL"1. The phytochemical screening of the flours was determined using standard qualitative methods indicated the presence of cyanogenic glucosides, tannins and flavonoids in all the three varieties studied but beebot and riyom contained alkaloids in addition. The extracts of the 3 varieties of rizga had a low toxic effect on the rats studied in addition with an LD50 of 630.1 mg kg'1 for Riym, 398.1 mg kg""1 for Langaat and 446.7 mg kg""1 for Beebot. Correlation between the total antioxidant capacity and polyphenolic composition of the 3 varieties of rizga was found to be significant (R2 = 0.917). These findings suggest rizga to be a natural source of antioxidants and thus could be used in the treatment of ailments implicating free radicals. In addition, it is safe for consumption.
收起
摘要 :
The present study was conducted to determine differences in antioxidant levels of fresh, frozen, and freeze-dried strawberries, and strawberry jam. Hydrophilic antioxidant activity (HAA) and lipophilic antioxidant activity (LAA) w...
展开
The present study was conducted to determine differences in antioxidant levels of fresh, frozen, and freeze-dried strawberries, and strawberry jam. Hydrophilic antioxidant activity (HAA) and lipophilic antioxidant activity (LAA) were measured using the ABTS/H2O2/HRP decoloration method. HAA and LAA were then summed to calculate the total antioxidant activity (TAA). Mean differences in HAA and LAA were analyzed using one-way analysis of variance and Dunnett's T3 pairwise comparisons. The mean TAA for freeze-dried strawberries based on an 'as consumed' weight (95% confidence interval [CI]: 29.58, 30.58) was significantly higher than for fresh (95% CI: 3.18, 3.66), frozen (95% CI: 2.58, 2.79), and jam (95% CI: 1.10, 1.22). The mean TAA based on dry weight for fresh strawberries (95% CI: 40.48, 46.67) was significantly higher than for freeze-dried (95% CI: 29.58, 30.58), frozen (95% CI: 24.62, 26.59), and jam (95% CI: 1.48, 1.64). Results agree with previous studies reporting that strawberries are a valuable source of antioxidants for consumers.
收起
原文获取