草莓、黑莓、蓝莓中多酚类物质及其抗氧化活性研究

研究草莓、黑莓、蓝莓3种小浆果的总酚、总黄酮、原花青素含量及其总抗氧化能力。结果表明:蓝莓全果的总酚、总黄酮、原花青素含量在所测3种浆果全果中最高,分别为9.44mg没食子酸/g干质量、36.08mg芦丁/g干质量、24.38mg儿茶素/g干质量;其总抗氧化能力也最强,达14.98mmol Trolox/100g干质量。草莓的总酚、总黄酮、原花青素含量则最低,抗氧化能力也最弱。此外,3种浆果果渣中的总酚、总黄酮、原花青素含量以及总抗氧化能力均高于全果和果汁,即果渣>全果>果汁。总酚含量、总黄酮含量以及原花青素含量与总抗氧化能力之间的相关性分析表明,总酚含量与总抗氧化能力之间存在显著线性相关,相关系数r达到0.9704,表明酚类物质是其抗氧化作用的主要物质基础。     

Physicochemical properties,antioxidant activity and cellular protective effects of honeys from southern Africa

The southern Africa region is a region of unique floral biodiversity; this study was undertaken to address the limited knowledge regarding the physiochemical, antioxidant activity and the ability of these honeys to protect biomolecules and cells against oxidative damage. The physicochemical properties, total polyphenolic and flavonoid content (TPC and TFC), catalase and antioxidant activity (DPPH, TEAC, and ORAC assays) of 13 representative honey samples was determined. Biological and cellular protection was investigated using the erythrocyte haemolysis, the pBR322 plasmid, as well as the dichlorofluorescein diacetate (DCFH-DA) assays in SC-1 and Caco-2 cells. High TPC, TFC, catalase and antioxidant activity was obtained, and all honeys protected DNA, erythrocytes and cells in vitro. Colour, TPC, TFC and antioxidant activity correlated well but no correlation was seen between these parameters and catalase activity, biological and cellular effects. Nevertheless, honeys with high catalase activity and/or are dark in colour with high TPC, TFC and/or antioxidant activity did show the highest degree of biological and cellular protection.     

Comparative analyses of phenolic composition, antioxidant capacity, and color of cool season legumes and other selected food legumes

ABSTRACT:  The objective of this study was to characterize the phenolic compounds and antioxidant activities of U.S.-produced cool season legumes. A total of 33 cool season legume samples were selected. Some common beans and soybeans were included for comparisons. Total phenolic content (TPC), total flavonoid content (TFC), and condensed tannin content (CTC) were analyzed. Ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, and oxygen radical absorbance capacity (ORAC) were used for analyzing antioxidant properties. Color of the legume flour and the seed coat was also analyzed. TPC, TFC, CTC, FRAP, DPPH, and ORAC values of legumes were significantly different not only between classes but also among samples within each class. Among cool season legume classes, lentils possessed the highest concentrations of the phenolic compounds and antioxidant activities. Colored common beans and black soybeans exhibited higher TPC, TFC, CTC, FRAP, DPPH, and ORAC values than those of yellow peas, green peas, and chickpeas. Antioxidant activities (FRAP, DPPH, and ORAC) were strongly correlated ( r = 0.96, 0.94, and 0.89, respectively, P < 0.01) with TPC. TPC and ORAC were moderately correlated ( P < 0.01) with either the seed hull surface color or the flour color.     

Antioxidant potential of wheat flour chapattis as affected by incorporating barley flour

Whole wheat flour was replaced with whole barley flour at levels of 28, 56 and 84 g/100 g to prepare chapattis and their antioxidant properties were evaluated before and after baking. The total phenolic content (TPC) in wheat flour was 2062 μg ferulic acid equivalents/g, total flavonoid content (TFC) was 966 μg catechin equivalents/g and antioxidant activity was 12.3% and they increased by 57.1, 101 and 22.6%, respectively upon incorporating barley flour at the highest level. Baking significantly decreased the TPC by up to 17.0% and TFC by up to 30.7% however the AOA increased by 13%. Barley flour incorporation significantly increased the reducing power which upon baking showed an insignificant decrease. Polyphenol oxidase (PPO) activity significantly increased by up to 109% upon incorporating barley flour however baking lowered PPO activity by 67.9%. Chapattis containing barley flour can be used to deliver the bioactive components of barley.     

Characterisation and comparison of phenols,flavonoids and isoflavones of soymilk and their correlations with antioxidant activity

To investigate the relationship between bioactive compounds and antioxidant property, total phenolic content (TPC), total flavonoid content (TFC), individual and total isoflavone content of soymilk and their correlations with oxygen‐radical‐absorbing capacity (ORAC), ferric reducing antioxidant power (FRAP) and 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging capacity values were evaluated and compared. Results showed that TPC, TFC, isoflavones (including concentration and profiles) and antioxidation activity significantly varied among ten tested soybean cultivars. Significant correlations were established between DPPH and TFC (r = 0.553, P < 0.01), DPPH and TPC (r = 0.753, P < 0.01), FRAP and TFC (r = 0.599, P < 0.01) and FRAP and TPC (r = 0.616, P < 0.01). Positive linear correlations were found between subtotal, total isoflavones and ORAC. Unlike other isoflavone monomers, aglycone isoflavones correlated positively with DPPH and FRAP significantly. DPPH well correlated with FRAP, whereas neither DPPH nor FRAP correlated with ORAC. TPC, TFC, individual and total isoflavone values are potentially useful for soymilk antioxidant activity assessment.     

Protective Effects of Merlot Red Wine Extract and its Major Polyphenols in Pc12 Cells under Oxidative Stress Conditions

Abstract: The potential effect of the extracts from free‐run and pressed Merlot red wine has been evaluated in PC12 cells under oxidative stress situation. Comparing both vinification process, pressed Merlot red wine extract possessed higher neuroprotective activity than the free run wine, possibly attributed to the major content in all global polyphenolic families. High performance liquid chromatography determination of individual polyphenols showed that the major compounds found in Merlot red wine extract were quercetin, catechin, epicatechin, tyrosol, gallic acid, and procyanidins. Pretreatments with these polyphenolic compounds (0.25 mM and 0.1 mM, 24 h) significantly increased cell viability of H₂O₂ and Fenton reaction treated cells. Moreover, these polyphenols attenuated ROS production and decreased the Redox Index of glutathione (RI = GSSG/GSH + GSSG) in cells treated only with Fenton reaction. Furthermore, some polyphenols induced antioxidant enzymes activity and protein expression. Quercetin was the most active. These results support the beneficial effects of red wine extracts and some of its polyphenols under oxidative stress conditions. Practical Application: This research provides evidences of the preventive properties of wine extracts and its major polyphenols under oxidative stress conditions.     

Effect of thermal and non-thermal processing on antioxidant potential of cowpea seeds

Legumes are a good source of bioactive components, besides being nutrient dense. These components have antioxidant properties and have a protective role against free radicals. Legumes like cowpeas are usually consumed after certain processing, so the present study was intended to assess antioxidant property of selected four cultivars of cowpea after going through various thermal (autoclaving, microwave, boiling, and roasting) and non-thermal (soaking and fermentation) processings. Thermal processing reduced total phenolic content (TPC), total flavonoid content (TFC), and ferric reducing antioxidant power (FRAP) in all cultivars with respect to antioxidant activity of raw cultivars, while DPPH scavenging activity increased after all thermal treatments excluding few thermal processings. Non-thermal processing revealed increase in TPC, DPPH scavenging activity, and FRAP values, while TFC content showed a decreasing trend. A moderately high correlation between TPC and DPPH scavenging activity was observed in both kinds of thermal treatments indicating the role of phenolic compounds for antioxidant activity. It was concluded from the study that fermentation processing has promising effects on retention and enhancement of antioxidant activity of cowpea cultivars.     

A novel antioxidant source: evaluation of in vitro bioaccessibility,antioxidant activity and polyphenol profile of phenolic extract from black radish peel wastes (Raphanus sativus L. var. niger) during simulated gastrointestinal digestion

The aim of this study was to evaluate the potency of polyphenolic extract from black radish (Raphanus sativus L. var. niger) root peel waste (PEBRRP) as an antioxidant food additive. PEBRRP was found a powerful antioxidant extract, in which had 172.9 ± 11.5, 462.72 ± 3.05, and 796.51 ± 10.4 mg TE per g dw of total antioxidant capacity (TAC) by CUPRAC, DPPH, and FRAP assays, respectively. The total phenolic content (TPC) and total flavonoid content (TFC) of PEBRRP were found as 305.51 ± 5.2 mg GAE per g dw and 171.58 ± 6.2 mg CAE per g dw, respectively. The ferulic acid (28.02 ± 4.5 mg per g dw) and epicatechin (19.82 ± 3.6 mg per g dw) were identified as the main polyphenols in undigested PEBRRP. The bioaccessibility of total phenolic and total flavonoid compounds of PEBRRP was found approximately 5%, and the antioxidant capacity of bioaccessible PEBRPP fraction was determined 6% in CUPRAC, 36% in DPPH and 47% in FRAP methods.     

Changes in polyphenolic content and antioxidant activity after thermal treatments of grape seed extract and grape pomace

This study was undertaken to investigate the effect of heat treatment on polyphenolic content and antioxidant activity in grape pomace (GP) and grape seed extract (GSE). GP and GSE were heat treated in a furnace or autoclaved at 100 °C for 15, 30 and 60 min. Structural modifications of the polyphenols during thermal processes were determined by HPLC–MS, and the antioxidant activity was determined by ABTS, DPPH and photochemiluminescence methods. In general, furnace thermal treatment of GSE and GP did not affect the total extractable polyphenols content, tannin content, procyanidin components and the antioxidant activity. Autoclave treatment caused an extensive hydrolysis of gallocatechin (70%), catechin (61%), epicatechin (65%), procyanidin B1 (75%) and procyanidin B2 (73%) in GSE, and an increase in gallic acid (71%), gallocatechin (100%) and epicatechin gallate (129%) in GP. Autoclave treatment did not affect the antioxidant activity of GSE or GP. It can be concluded that the effect of autoclave was more severe than furnace heat treatment modifying the phenolic profile in a different manner depending on the grape seed product used. These modifications were not related with changes in antioxidant activity.     

Influence of solvent and temperature on extraction of phenolic compounds from grape seed,antioxidant activity and colour of extract

This study was aimed to investigate the influence of solvent (water and ethanol in concentration: 50%, 70% and 96%) and extraction temperature (25–80) °C on polyphenols extraction of grape seed (Vitis vinifera L. cv. “Frankovka”) cultivated in Eastern Croatia. The best results were reached using 50% ethanol at 80 °C. The most abundant individual polyphenolic compound was catechin which makes the average of 45.11% of the total phenolic content followed by epicatechin (34.45%), procyanidin B₂ (12.90%), gallic acid (5.34%), gallocatechin (1.58%), epicatechin gallate (1.01%). The antioxidant activity of extracts was determined by DPPH‐method and it was highly dependent on extraction solvent and temperature. The total extractable proanthocyanidins content of extract had the highest positive correlation (r = 0.994) with antioxidant activity, which indicated that these compounds might be the most important antioxidant in examined grape seed extracts. Relationship between phenolic content and colour of extracts was observed.     

Differences in the amount and structure of extractable skin and seed tannins amongst red grape varieties

Background and Aims:  Red wine is a very rich source of flavanols, consisting of catechins and oligomeric and polymeric proanthocyanidins (PAs). The aim of this study was to investigate the composition of the fraction of flavanols, which is extractable from the grape into the wine.
Methods and Results:  Using HPLC-DAD-MS analysis carried out before and after thioacidolysis of wine-like extracts obtained from skins and seeds, the flavanol composition of 20 samples derived from Cabernet Sauvignon, Carmenere, Marzemino, Merlot, Pinot Noir, Syrah and Teroldego was determined.
Conclusions:  It was confirmed that grape extracts are mainly rich in monomers and small oligomers (mean degree of polymerization <8). Grape seed extracts contained three monomers (catechin, epicatechin and epicatechin gallate) and procyanidin oligomers. Grape skin extracts contained four monomers (catechin, epicatechin, gallocatechin and epigallocatechin), procyanidins and prodelphinidins oligomers. Upper and extension units of PAs were constituted mainly of epicatechin units, with the co-presence of catechin and epicatechin gallate in the seed PAs, and of gallocatechin in the case of skin PAs. The terminal units of the grape PAs were a mixture of five compounds, the same found also as monomers. Catechin gallate, gallocatechin gallate and epigallocatechin gallate, which are found in other flavanol-rich, plant-derived foods and beverages, were not present in grape extracts.
Significance of the Study:  The grape variety determines both the amount and the structure of wine flavanols, leading to differences in the composition, which are likely to play an important role in the nutritional and sensorial properties of the wines.     

丝瓜花不同溶剂提取物抗氧化活性及其酚类成分分析

以无水乙醇、70%乙醇、40%乙醇和水分别对丝瓜花进行提取,并测定各提取物中总酚、总黄酮含量,采用DPPH·清除能力、超氧化物自由基清除能力、FRAP抗氧化能力和亚铁离子螯合能力等方法评价其抗氧化活性,通过HPLC分析其中酚类成分。结果表明,70%和40%乙醇提取物总酚及总黄酮含量较高,而且DPPH·清除活性、FRAP还原力最强,40%乙醇提取物、水提物分别具有最强的超氧阴离子自由基清除活性和亚铁离子螯合能力。总酚含量与DPPH·清除活性之间存在较强的相关性(R²=0.8688)。HPLC分析检出提取物中9种酚类化合物,其中含量最高的为杨梅素。试验结果说明,70%乙醇、40%乙醇可能是丝瓜花抗氧化性物质提取的较好溶剂。结果表明丝瓜花是一种较好的抗氧剂资源。     

Rapid Determination of Antioxidant Compounds and Antioxidant Activity of Sudanese Karkade (<Emphasis Type="Italic">Hibiscus sabdariffa</Emphasis> L.) Using Near Infrared Spectroscopy

The extraction conditions applied in destructive analysis of Hibiscus sabdariffa L. (Hs) matrices before the measurement of antioxidant compounds may reduce their activities during isolation and purification due to decomposition. Hence, near infrared spectroscopic system was applied to determine these compounds. The calibration models developed by using partial least squares regression (PLSR) with 48 Hs samples and 24 unknown samples were used to confirm the robustness of the developed model. The results of calibration models effectively allowed the determination of the concentrations of total phenol content (TPC), total flavonoid content (TFC), total antioxidant content (TAC), ferric reducing antioxidant power (FRAP), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) with high correlation coefficients (0.85–0.91) and small standard error of cross-validation (RMSECV) ranged from 0.08 to 0.33. The prediction capacity (RPD) for TPC, TFC, TAC, FRAP, and DPPH ranged from 3.30 to 8.25, thus demonstrating that the near infrared spectroscopic (NIRS) equations developed were applicable to unknown samples. This study demonstrates that NIRS can be considered as a fast tool for the nondestructive determination of antioxidant compounds (phenolics and flavonoids) and antioxidant activity of the Hs.     

不同品种山楂活性成分及其抗氧化活性的研究

本文以产自山东地区的山里红和大金星这两个常见山楂品种作为研究对象,山楂冻干制成粉末后测定它们的总酚、总黄酮含量及抗氧化活性(DPPH、ORAC和PSC),并采用HPLC分析抗氧化活性成分的差异。结果显示不同品种山楂中的总酚和总黄酮含量各异,其中山里红果实的总酚(61.91 mg GA equiv./g DW)和总黄酮(55.96 mg catechin equiv./g DW)含量均显著高于大金星。山楂果实提取物均有较好的抗氧化活性,其中山里红品种表现出更好的抗氧化活性,其ORAC及PSC值分别是大金星的1.54和2倍。山楂果实提取液经HPLC法分析,鉴定出7种多酚类化学成分,最主要的酚类化合物为原花青素B2以及表儿茶素,且山里红果实多酚类化合物的含量显著高于大金星。综合比较发现山楂中的活性成分含量及种类各异,且山里红的抗氧化活性较强,是天然抗氧化剂的潜在原料。     

Major Polyphenolics in Pineapple Peels and their Antioxidant Interactions

Major polyphenolic compounds in pineapple peels were identified and quantified. The antioxidant capacities of pineapple peel extracts and these polyphenolic compounds were determined using DPPH? scavenging capacity and phosphomolybdenum method. Effects of these polyphenolics’ interactions on their antioxidant capacity were also evaluated. Gallic acid (31.76 mg/100 g dry extracts), catechin (58.51 mg/100 g), epicatechin (50.00 mg/100 g), and ferulic acid (19.50 mg/100 g) were found to be the main polyphenolics in pineapple peels. The IC₅₀ for DPPH? scavenging assay of the extracts was 1.13 mg/ml and total antioxidant capacity was 0.037 g ascorbic acid equivalents/g. The order of DPPH? scavenging capacity of per mole of these polyphenolic compounds present in pineapple peels was gallic acid > epicatechin = catechin > ferulic acid, but it was different when using phosphomolybdenum method the order of which was epicatechin. > catechin > gallic acid = ferulic acid. Results of polyphenolics’ interactions indicated no synergistic effects. In the combinations of ferulic acid-epicatechin and ferulic acid-gallic acid, additive effects were found using both antioxidant activity assays.     

Proanthocyanidin profile and antioxidant capacity of Brazilian Vitis vinifera red wines

The free flavan-3-ol and proanthocyanidin (PA) profile and the antioxidant capacity of wines Vitis vinifera L., 2006 and 2007 vintages, from the São Joaquim region, at southern Brazil, are reported here for the first time. Catechin and epicatechin were the two main monomers in the wine samples, followed by gallocatechin and epigallocatechin; and the PA B1 was the main dimer. The terminal units of the PAs were constituted mainly by catechin units, with the co-presence of epicatechin, gallocatechin, epigallocatechin and traces of epicatechin gallate. The epicatechin and epigallocatechin units were the main constituents of the extension units of PAs with the co-presence of catechin and epicatechin gallate. The values for the mean degree of polymerisation ranged from 4.9 to 9.8. The wine samples demonstrated effective scavenging activity against DPPH and ABTS radicals and against lipid peroxidation in vitro. A positive correlation existed between flavan-3-ol content and antioxidant capacity in vitro.     

绿茶、橘皮、大豆中酚类物质体外消化前后稳定性及抗氧化活性的研究

本研究以富含3类代表性酚类化合物（黄烷醇、黄烷酮和异黄酮）的3种食物（绿茶、橘皮、大豆）作为原料,模拟其在人体口胃肠中的体外消化过程。采用高效液相色谱-二极管阵列检测器/电喷雾-四极杆-飞行时间串联质谱检测器（HPLC-DAD/ESI-Q-TOF-MS）检测体外消化前后酚类化合物的种类及含量变化,同时测定不同消化阶段总酚含量（TPC）、总黄酮含量（TFC）以及抗氧化活性（DPPH、ABTS、FRAP、ORAC）的变化。结果表明,绿茶提取物中检测出4种酚类化合物（表没食子儿茶素、(+)-儿茶素、表没食子儿茶素没食子酸酯和表儿茶素没食子酸酯）,大豆提取物中检测出4种酚类化合物（大豆苷、染料木苷、大豆苷元和染料木素）,橘皮提取物中检测出2种酚类化合物（柚皮苷和橙皮苷）;三种食物提取物中,经过体外消化后,绿茶提取物中的酚类化合物最不稳定,除(+)-儿茶素外,其余3种酚类物质几乎降解完全,损失率均达95%以上。绿茶、橘皮、大豆提取物的TPC在胃消化阶段显著升高（P<0.05）,在肠消化阶段显著降低（P<0.05）。绿茶提取物TFC在口腔和胃消化阶段显著升高（P<0.05）,在肠消化阶段显著降低（P<0.05）。橘皮、大豆提取物TFC与TPC变化趋势一致。绿茶提取物的四种抗氧化活性经胃肠消化后呈先升高再降低的趋势。大豆提取液体外消化前后ABTS、FRAP抗氧化活性在口腔阶段显著降低（P<0.05）,DPPH、ORAC抗氧化活性在口腔、胃消化阶段显著升高（P<0.05）,在肠消化阶段显著降低（P<0.05）。橘皮提取液ORAC抗氧化活性在肠消化阶段显著升高（P<0.05）,ABTS、FRAP抗氧化活性在体外消化阶段均表现出和总酚含量变化一致的趋势。     

Antioxidant activities of aqueous extracts of selected plants

The antioxidant properties of 25 edible tropical plants, expressed as Trolox equivalent antioxidant capacity (TEAC), were studied using DPPH (1,1-diphenyl-2-picrylhydrazyl free radical) scavenging and reducing ferric ion antioxidant potential (FRAP) assays. Their cupric ion chelating activities (CCA) and total polyphenol contents (TPC) were also determined. A strong correlation between TEAC values obtained for the DPPH assay (TEAC_DPPH) and those for the FRAP assay (TEAC_FRAP) implied that compounds in the extracts were capable of scavenging the DPPH free radical and reducing ferric ions. A satisfactory correlation of TPC with TEAC_DPPH and TEAC_FRAP suggested that polyphenols in the extracts were partly responsible for the antioxidant activities while its correlation with CCA was poor, indicating that polyphenols might not be the main cupric ion chelators. Principal component analysis (PCA) indicated that TEAC_DPPH, TEAC_FRAP and TPC contributed to the total variation in the antioxidant activities of the plants.     

Effect of drying methods on volatile compounds,fatty acids and antioxidant property of Thai kaffir lime (Citrus hystrix D.C.)

This study investigated the changes in colour, volatile compounds, fatty acids, total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity of kaffir lime leaves (makrud in Thai) Citrus hystrix D.C. after three drying treatments, namely hot‐air (HA) drying, low relative humidity (LRH) air drying and far‐infrared radiation (FIR) drying. Overall, when compared with fresh leaves, a slight decrease in L* values of the three dried samples was observed. TPC, TFC and ferric‐reducing/antioxidant power (FRAP) values were increased by LRH and FIR drying (LRH: 39%, 43% and 28%; FIR: 62%, 39% and 39%), while HA drying decreased TPC, TFC and FRAP values (28%, 21% and 1%), compared with fresh leaves. The main volatile compounds in fresh leaves were citronellal, followed by linalool and viridiflorol. Drying brought about an increase in the concentrations of volatile components, such as citronellal with HA, LRH and FIR drying (79%, 83% and 64%, respectively), compared with the results for fresh leaves (56%). LRH and HA drying increased essential fatty acid alpha‐linolenic acid (ALA, 18:3n‐3), while linoleic acid (LA, 18:2n‐6) was increased by FIR drying. The present study has provided useful information for the industrial use of dried kaffir lime production.