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1.
Pomegranates contain a complex mixture of gallotannins, ellagitannins, ellagic acid and anthocyanins. However, label claims on pomegranate supplements (PS) may not correlate with actual content of antioxidants, polyphenols or tannins. Nineteen PS were evaluated for their authenticity by determining ellagitannin composition by RP-HPLC and studying the relationship between total polyphenols as measured by the Folin–Ciocalteau assay and antioxidant capacity by oxygen radical absorbing capacity (ORAC), free radical scavenging properties by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and ferric reducing antioxidant power (FRAP). Only a limited number of pomegranate supplements were authentic. Product labels were inconsistent with polyphenol composition and antioxidant content. A majority of the samples (n = 13) contained disproportionately high amounts of ellagic acid and low or no detectable pomegranate tannins. Only six products had tannin composition that resembled pomegranates (punicalagin, punicalin, ellagitannins and gallotannins). PS-01 (natural pomegranate extract) was the most representative of pomegranate fruit polyphenols with 99% total pomegranate polyphenol and the highest antioxidant capacity across all measures. Correlations between total polyphenols and antioxidant content were high (R2 > 0.87) in products that had polyphenol composition resembling pomegranates. Products that contained high amounts of ellagic acid and low or no detectable pomegranate tannins had poor correlations between total polyphenols and antioxidant content. The results indicate that reliable labeling information, better standardization, improved manufacturing practices and regulation of the market is required to assure consumers of the quality of pomegranate supplements.  相似文献   

2.
BACKGROUND: The objectives of this study were (1) to evaluate the content of ellagic acid in fruits consumed by the Brazilian population, including native ones; (2) to further characterize rich sources in relation to ascorbic acid, phenolics contents and in vitro antioxidant capacity; and (3) to study the distribution and effect of ripening stage on ellagitannins content of jabuticaba (Myrciaria jaboticaba). The content of free ellagic acid and ellagic acid derivatives such as ellagitannins was analyzed using high‐performance liquid chromatography (HPLC). RESULTS: Ellagic acid was detected in 10 out of a total of 35 fruits analyzed. The content of free ellagic acid in fruits varied from 0.0028 to 0.085 g kg?1 (FW) and total ellagic acid varied from 0.215 to 3.11 g kg?1 (FW). All the seven fruits belonging to the Myrtaceae family evaluated in this study presented high contents of ellagitannins in their composition, with jabuticaba, grumixama and cambuci (all native from Brazil) showing the highest total ellagic acid contents. Jabuticaba, the most consumed in Brazil among those and already adapted to commercial plantations, contained concentrated phenolics compounds, including ellagitannins, in the peel. Anthocyanins (cyanidin derivatives) increased significantly through ripening of jabuticaba and were not present in the pulp or seeds. Samples collected from three different locations during summer, winter and spring had total ellagic contents varying from 1.88 to 3.31 g kg?1 (FW). The decrease in ellagic acid content with ripening was more accentuated for pulp (eight times) compared to seeds (2.3 times) and peel (2.0 times). CONCLUSION: These results showed the potential of jabuticaba as dietary source of ellagic acid and reinforced consumption of the whole fruit by the population. Copyright © 2011 Society of Chemical Industry  相似文献   

3.
The anti-oxidant content and potential health benefits associated with consuming pomegranate and pomegranate-containing products has lead to increased consumer demand for this crop resulting in it becoming a high value crop. The potential health benefits and high anti-oxidant content of this fruit is attributed to the polyphenolic compounds it contains, including the ubiquitous phenolic acids, gallic acid and ellagic acid, and punicalagin A and punicalagin B, two polyphenolics unique to this fruit. A rapid HPLC–UV method targeting these four metabolites requiring minimal sample cleanup and offering runtimes half as long as existing methods was established. Within day and inter-day run-to-run variability for the four metabolites ranged from 1.9% to 6.6% and 5.3% to 11.4%, respectively. Spike recovery percentages for gallic acid, punicalagin A, punicalagin B and ellagic acid were found to be 98.5%, 92.4%, 95.5%, and 96.5%, respectively. This method was applied to the evaluation of various pomegranate products, including commercial drinks, handmade juice, and marc extracts. This method may be readily used to verify the presence of pomegranate metabolites in juices, extracts, and other products.  相似文献   

4.
The molecular structures of the radical scavenging compounds present in extracts of Potentilla fruticosa blossoms were elucidated and the antioxidant activities of various extracts were determined. The activities of the different fractions were monitored by off‐line and on‐line RP‐HPLC DPPH? and ABTS?+ scavenging methods. Twelve compounds were isolated and identified, namely ellagic acid, catechin, quercetin‐3‐β‐glucopyranoside, quercetin‐3‐β‐galactopyranoside, quercetin‐3‐β‐rutinoside, quercetin‐3‐β‐glucuronopyranoside, quercetin‐3‐α‐arabinofuranoside, kaempferol‐3‐β‐rutinoside, kaempferol‐3‐O‐β‐(6″‐O‐(E)‐p‐coumaroyl)glucopyranoside, rhamnetin‐3‐β‐glucopyranoside and rhamnetin‐3‐β‐galactopyranoside. The radical scavenging activity of each isolated compound was measured using DPPH? and ABTS?+ assays and compared with the activity of rosmarinic acid. Catechin and ellagic acid were found to be the most active radical scavengers. The antioxidant properties of plant fractions were assessed in model systems by measuring superoxide anion and hydrogen peroxide scavenging, β‐carotene bleaching, hexanal production in edible oil, peroxide formation, and the increase in UV absorbance in the course of oxidation. Copyright © 2004 Society of Chemical Industry  相似文献   

5.
BACKGROUND: The commercial development of plants as sources of antioxidants that can be used to enhance the properties of foods, for nutritional purposes and preservation as well as for prevention of oxidation‐related diseases, is currently of major interest. Rosehip (Rosa canina L.) is a rich source of vitamin C and polyphenols. RESULTS: Phytochemicals in rosehip tea were separated into three fractions: Fr1 (vitamin C, 39.17 mg kg?1), Fr2 (flavonoids, 451.05 µg kg?1) and Fr3 (phenolic acids, 504.69 µg kg?1). Quercetin and ellagic acid were the most abundant polyphenolic compounds. Rosehip fractions, primarily rosehip flavonoids (EC50 = 49 mg L?1), showed high antioxidant activity towards 2,2‐diphenyl‐1‐picrylhydrazyl radicals (DPPH?). Cell growth effects of rosehip fractions were assessed in HeLa, MCF7 and HT‐29 cell lines, with the lowest IC50 values being determined for rosehip flavonoids, (80.63, 248.03 and 363.95 mg L?1 respectively). However, the vitamin C fraction did not inhibit the growth of tested tumour cells. CONCLUSION: The results of this study confirm that vitamin C and flavonoids are responsible for the antioxidant activity of rosehip tea, while only polyphenols contribute to its antiproliferative activity. Copyright © 2011 Society of Chemical Industry  相似文献   

6.
BACKGROUND: Strawberries are nutritive fruits and a source of antioxidants. We evaluated antioxidant properties of ‘Camino Real’ strawberries grown in the Brazilian savannah, harvested in different seasons. Analytical and meteorological data were analyzed by partial least squares regression. RESULTS: Fruits from May showed the lowest contents of total phenolics (1789.78 mg kg?1 fresh weight (FW)), catechin (21.37 mg kg?1 FW), quercetins (4.89 mg kg?1 FW) and total ellagic acid (208.68 mg kg?1 FW) and the lowest antioxidant activity by 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) (11.39 mg Butylated hydroxytoluene (BHT) eq. g?1 FW) and ferric reducing antioxidant power (FRAP) (22.01 mg ferrous sulfate eq. g?1 FW) assays. Strawberries harvested in July presented the lowest concentrations of total (190.61 mg kg?1 FW) and individual anthocyanins (73.88 mg kg?1 FW and 5.96 mg kg?1 FW for pelargonidin‐3‐glucoside and cyanidin‐3‐glucoside, respectively), but the highest contents of vitamin C (685.47 mg kg?1 FW), DPPH (18.87 mg BHT eq. g?1 FW) and FRAP (39.30 mg ferrous sulfate eq. g?1 FW). The highest contents of free ellagic acid (26.11 mg kg?1 FW), pelargonidin‐3‐glucoside (291.82 mg kg?1 FW) and cyanidin‐3‐glucoside (11.84 mg kg?1 FW) were found in strawberries from September. Rain in the previous 30 days to harvest influenced negatively many phenolics and antioxidant activity of strawberries harvested in May. In July, longer photoperiod and lower temperature at 30 days previous to harvest probably led to higher antioxidant activity and vitamin C. Increased photoperiod and temperature at the final stage of maturation seem to raise pigments and free ellagic acid in strawberries. CONCLUSION: It was possible to observe significant relationships among meteorological and antioxidant variables for strawberries grown in the Brazilian savannah. Copyright © 2011 Society of Chemical Industry  相似文献   

7.
Sour cherry (Prunus cerasus L.) cultivars native to Hungary and some of them grown worldwide, display great phenotypic variability. Eleven sour cherry cultivars were analysed for their main quality attributes including fruit weight, soluble solid content, acidity, pH, specific sugars (glucose and fructose), antioxidant capacity as well as total polyphenolic (TPC), total anthocyanin (TMAC) and vitamin C contents. Results showed wide variation in both fruit quality and antioxidant parameters of Hungarian sour cherries. The anthocyanin contents varied from 11.3 to 93.5 mg/100 g. An amarelle‐type cultivar, ‘Pipacs 1’ showed the highest antioxidant capacity (21.85 mmol AA L?1), TPC (49.04 mg GA L?1) and vitamin C (8.98 mg/100 g) content. Key enzymes in anthocyanin biosynthesis were expressed in both yellow‐coloured flesh and red skin of ‘Pipacs 1’ fruits at all ripening stages. The detected diversity presents a choice that can satisfy different consumer preferences, and meet specific nutritional requirements.  相似文献   

8.
BACKGROUND: The fresh‐cut industry produces thousands of tons of waste in non‐edible portions that present an environmental and management problem. These by‐products could be reused, in particular, to obtain bioactive compounds. In this study, five different fresh‐cut watermelon cultivars were assessed for their flesh and by‐product bioactive contents. RESULTS: The amount of by‐product varied between 31.27 and 40.61% of initial fresh weight (f.w.) depending on the cultivar. Watermelon cultivars were poor sources of total antioxidant, and the content was similar between rind and flesh samples (46.96 vs 43.46 mg ascorbic acid equivalent antioxidant capacity kg?1 f.w.). However, the rind had a moderate total phenolic content higher than that of the flesh (458 vs 389 mg chlorogenic acid equivalent kg?1 f.w.) and a much higher content of the amino acid citrulline (3.34 vs 2.33 g kg?1 f.w.), which has potential bioactive properties. CONCLUSION: Watermelon rind offers quantitative interest as a natural source of citrulline, particularly Fashion, a dark‐skinned, seedless cultivar. More research is required on the efficient extraction of citrulline from watermelon rind and its suitability as an additive to drinks, juices or others products to produce new functional food products with valid health claims. Copyright © 2010 Society of Chemical Industry  相似文献   

9.
对云南水晶石榴果皮中的多酚含量和组成进行了分析,并研究了其提取物的抗氧化活性。结果表明:云南水晶石榴果皮中多酚含量为99.60 mg/g(干重);香豆酸、儿茶素和原儿茶酸是多酚的主要成分,含量分别为4.80、3.96和1.96 mg/g(干重)。多酚提取物的还原能力、DPPH自由基清除能力、抑制脂质体过氧化能力和清除亚硝酸盐能力较强,且与浓度显著性正相关(P<0.01),相关性系数(R2)在0.888 1~0.995 8。  相似文献   

10.
Thirty six commercial European fruit juices were tested to ascertain their antioxidant capacity and polyphenolic composition. Six of the products were labelled 100% pomegranate juice, the others included 20 brands of diluted pomegranate juice or pomegranate blended with other fruit juices and 10 different non-pomegranate fruit juices. The antioxidant capacity of all the juices was determined while anthocyanin, ellagitannin and ellagic acid profiles of the 26 pomegranate juices and pomegranate juice blends were obtained using HPLC-PDA-MS(2). Additional analysis was conducted on seven of the juices using HPLC with an on-line antioxidant detection system. Three of the "pure" pomegranate juices had the highest ellagitannin content and the highest antioxidant capacity. Only one of these three juices was rich in anthocyanins. The other "pure juices" had differences in their HPLC "pomegranate" fingerprint and also had a lower antioxidant capacity, in some cases lower than that of some of the blended juices. Vitamin C rather than phenolic compounds was the major contributor to the antioxidant capacity for some of the juices. Statistical analysis of both the antioxidant assay and the HPLC on-line antioxidant data demonstrated that the ellagitannins were the major antioxidants in the pomegranate juices. The complexity of the polyphenolic profile of pomegranates necessitates the use of HPLC-PDA-MS(2) for a thorough evaluation of juice composition and authenticity.  相似文献   

11.
BACKGROUND: The Folin–Ciocalteu method is routinely used to calculate total polyphenol concentrations (TPP) in food products. However, the use of inappropriate standards such as gallic acid (GA) may give inaccurate estimates of TPP content. A method for the production of a pomegranate (Punica granatum L. ‘Wonderful’) standard was developed and validated to avoid this problem. The PPS was produced by solid phase (C18) isolation of polyphenols from POMx powder (a nutritional supplement) and used for TPP analysis. RESULTS: TPP content of POMx was > 90% using PPS, whereas the GA standard underestimated TPP by up to 30%. Compositional analysis confirmed a balance of about 9% non‐polyphenolic compounds. Mass spectrometry analysis corroborated polyphenol composition and confirmed pomegranate‐specific peaks, i.e., punicalagin and punicalin. CONCLUSION: Results support the use of pomegranate‐specific standards to accurately determine TPP. Copyright © 2008 Society of Chemical Industry  相似文献   

12.
In this study, total phenolic contents and antioxidant activities of grape seed extracts obtained from twelve different grape seeds from common varieties grown in Turkey were determined. Grape seeds were extracted with 70% acetone and extraction yield of grape seed were calculated. The total phenolic content of grape seed extracts were determined by the Folin‐Ciocalteu procedure and ranged from 33 945 to 58 730 mg per 100 g extract as gallic acid equivalent. Antioxidant activities of grape seed extracts with two different free radical scavenging methods, ABTS [2,2/‐azinobis (3‐ethylbenzothiazoneline‐6‐sulfonic acid)] and DPPH (2,2‐diphenyl‐picrylhydrazyl) assays, using Trolox equivalent as standards, were investigated. Grape seed extracts exhibited antioxidant activities 2.46–4.14 and 3.55–5.76 [Trolox equivalent antioxidant capacities (TEAC) mg?1 extracts] in ABTS and DPPH assays, respectively. Compared with varieties, Muskule extracts exhibited the lowest total phenolic content, TEACABTS and TEACDPPH value while Narince extracts had the highest total phenolic content and TEACDPPH value, and Alphonse Lavalleé had the highest TEACABTS value. Total phenolic content showed that there is a significant correlation with TEACDPPH (r = 0.7974, P ≤ 0.001) and TEACABTS values (r = 0.4860, P ≤ 0.05).  相似文献   

13.
14.
Stem and pomace of a white grape (Vitis vinifera) variety, Prensal Blanc, were studied for the first time: general composition and dietary fibre components together with the total soluble polyphenol content and antioxidant activity. Both by‐products present high contents of total dietary fibre (TDF), 790 g kg?1 d.m. (stem) and 716 g kg?1 d.m. (pomace). Values of the soluble dietary fibres in relation to TDF differed: 5% (stem) and 14.4% (pomace). Similar values of Klason lignin were found: 229 g kg?1 (stem) and 278 g kg?1 (pomace), however, the pomace exhibited more than twice the content of the condensed tannins (168 g kg?1) with regard to the stem (79 g kg?1). Notable were the high resistant protein contents of both by‐products. Stem and pomace showed appreciable amounts of total soluble polyphenols (87 g kg?1 against 35 g kg?1 respectively). The free radical scavenging capacity of the former by‐products was determined using the 2,2‐diphenyl‐1‐picrylhydrazyl radical (DPPH) method, obtaining EC50 values of 0.79 g d.m. g?1 DPPH (stem) and 1.32 g d.m. g?1 DPPH (pomace). These data shows that both vinification by‐products from the Prensal Blanc variety are a good source of dietary fibre and have antioxidant properties.  相似文献   

15.
Abstract: Phenolics, flavonoids, anthocyanins, and tannins of pomegranate juices, obtained from 9 Tunisian ecotypes were quantified. Phenolics and flavonoids in the variety Tounsi (TN) (3299 mg gallic acid equivalents [GAE]/L and 636 mg quercetin equivalents [QE]/L of juice, respectively) were higher than in the variety Gabsi (GB) (1570 mg GAE/L and 135 mg QE/L of juice, respectively). The highest anthocyanins quantity was found in GB 2 with 156 mg cyanidin‐3‐glucoside equivalents (CGE)/L. TN 3 ecotype showed the highest tannins quantity with 2550 mg catechin equivalents (CE)/L of juice. TN 1 presented the highest radical‐scavenging activity (2, 2′‐azinobis‐3‐ethylbenzothiazoline‐6‐sulphonate [ABTS], IC50 [50% inhibition concentration] = 525 mg/L), as well as the highest concentration of micronutrient cations (potassium and sodium). A high correlation (R2= 0.80) between antioxidant capacity and proanthocyanin contents was found, this suggests that proanthocyanins are the principal contributor in the antioxidant capacity of pomegranate. Our data suggest also that the high concentrations of K+ and Na+ may play a role in the adaptation of pomegranate to arid environments.  相似文献   

16.
BACKGROUND: Pinus halepensis (Aleppo pine) is a widespread tree that can be found in both natural and urban environments. A discrimination study based on the antioxidant compounds, antioxidant capacity and fatty acid (FA) profile of P. halepensis cones (PHC) and seeds (PHS) was performed. RESULTS: The total amount of phenols was about 72‐fold higher in PHC extract than in PHS extract (P < 0.001). Anthocyanin and carotenoid contents were 10‐ and 12‐fold higher respectively in PHC extract. PHC and PHS extracts at a concentration of 1 mg mL?1 differed significantly in free radical‐scavenging activity on 2,2‐diphenyl‐1‐picrylhydrazyl radical (DPPH?) (86.65 vs 16.97%). PHC had higher antioxidant ability on 2,2′‐azino‐bis(3‐ethylbenzothialozine‐6‐sulfonic acid) radical cation (ABTS?+) than PHS (EC50 0.368 vs 2.345 mg mL?1). The FA profile of PHC oil revealed its richness in saturated FAs (41.5%) and high levels of trans FA isomers, with a predominance of trans,trans ‐linoleic acid (4.74%). However, polyunsaturated FAs in PHS oil represented more than 64% of total FAs. CONCLUSION: PHC showed important antioxidant activities as well as high levels of bioactive compounds. Thus PHC is a potential source of natural antioxidants that may afford several health benefits. However, the lipid extract of PHS seems to have more nutritional value as a polyunsaturated oil than that of PHC, which is high in saturated and trans FAs. Copyright © 2011 Society of Chemical Industry  相似文献   

17.
In this study, the antioxidant capability, total phenolic content and antimicrobial activity of ethanolic extracts of seven fruits from the Brazilian Atlantic Forest were evaluated. The conditions for the extraction of crude phenolics from the fruits were determined using an experimental factorial design. Total phenolic content, 1,1‐diphenyl‐2‐picrylhydrazyl radical (DPPH?) scavenging activity and β‐carotene‐linoleic acid couple oxidation assays were used to evaluate the antioxidant properties of the extracts. In addition, antimicrobial activity was screened using two Gram‐negative bacteria (Escherichia coli and Klebsiella pneumoniae) and one Gram‐positive bacterium (Staphylococcus aureus). All native fruits assayed in this study have high potential as natural antioxidant sources. Among the seven fruits evaluated, Jabuticaba and Uvaia had the highest antioxidant activity in the DPPH? and of β‐carotene‐linoleic acid coupled oxidation assays. In the biological assay, K. pneumoniae was the most sensitive microorganism to the fruit extracts, and the Jabuticaba extract had a slight inhibitory effect against this Gram‐positive bacterium.  相似文献   

18.
BACKGROUND: Twenty‐seven Italian honey samples of different floral origin were analysed for total phenolic and flavonoid contents by a spectrophotometric method and for antioxidant power and radical‐scavenging activity by the ferric‐reducing/antioxidant power (FRAP) and 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) assays respectively. In addition, the phenolic and flavonoid profiles were analysed using high‐performance liquid chromatography with UV detection (HPLC‐UV). RESULTS: The results of this study showed that honey contains copious amounts of phenolics and flavonoids. HPLC‐UV analysis showed a similar qualitative polyphenolic profile for all honey samples analysed. The main difference among samples was in the contribution of individual analytes, which was affected by floral origin. Total phenolic and flavonoid contents varied from 60.50 to 276.04 mg gallic acid equivalent kg?1 and from 41.88 to 211.68 mg quercetin equivalent kg?1 respectively. The antioxidant capacity was high and differed widely among samples. The FRAP value varied from 1.265 to 4.396 mmol Fe2+ kg?1, while the radical‐scavenging activity expressed as DPPH‐IC50 varied from 7.08 to 64.09 mg mL?1. Correlations between the parameters analysed were found to be statistically significant (P < 0.05). CONCLUSION: The present study shows that honey contains high levels of phenolics and flavonoids and that the distribution of these compounds is influenced by the honey's floral origin. Copyright © 2009 Society of Chemical Industry  相似文献   

19.
BACKGROUND: Germination is considered to improve the nutritive value, antioxidant capacity and functional properties of grains. In this study, changes in the chemical composition, nutritive value and antioxidant capacity of waxy wheat during germination were determined. RESULTS: Over a 48 h period of germination the protein and free lipid contents of germinated waxy wheat were not significantly different from those of the control, whereas the bound lipid content decreased significantly. An increase in levels of ash and dietary fibre was clearly observed for the 48 h‐germinated wheat. The total free amino acid content of the 48 h‐germinated wheat was 7881 mg kg?1 flour (dry basis (d.b.)), significantly higher than that of the ungerminated wheat (2207 mg kg?1 flour, d.b.). In particular, γ‐aminobutyric acid increased from 84 mg kg?1 flour (d.b.) in the control to 155 mg kg?1 flour (d.b.) in the 48 h‐germinated wheat. Germination did not significantly affect the fatty acid composition of both free and bound lipids of waxy wheat, whereas free phenolic compounds increased during germination, resulting in an increase in antioxidant capacity of germinated wheat. CONCLUSION: Germinated waxy wheat had a better nutritional composition, such as higher dietary fibre, free amino acid and total phenolic compound contents, than ungerminated waxy wheat. Therefore germinated waxy wheat should be used to improve the nutritional quality of cereal‐based products. Copyright © 2011 Society of Chemical Industry  相似文献   

20.
Fatty acid synthase (FAS) has been recognized as a potential therapeutic target for obesity. In this study, for the first time, the inhibitory effect of pomegranate husk extract, punicalagin and ellagic acid on FAS was investigated. We found them potently inhibiting the activity of FAS with half-inhibitory concentration values (IC50) of 4.1 μg/ml (pomegranate husk extract), 4.2 μg/ml (4.50 μM, punicalagin) and 1.31 μg/ml (4.34 μM, ellagic acid), respectively. Moreover, they all exhibited time-dependent inactivation of FAS. Punicalagin and ellagic acid inhibited FAS with different mechanisms compared to previously reported inhibitors, through inactivating acetyl/malonyl transferase and β-ketoacyl synthase domains, respectively. Additionally, 100 μg/ml pomegranate husk extract, 5.24 μg/ml (5 μM) punicalagin and 4.5 μg/ml (15 μM) ellagic acid effectively reduced lipid accumulation inside FAS over-expressed 3T3-L1 adipocytes. Since FAS plays a key role in the biosynthesis pathway of fatty acid, these findings suggest that pomegranate husk extract, punicalagin and ellagic acid have potential in the prevention and treatment of obesity.  相似文献   

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