Release of antioxidant components from tomatoes determined by an in vitro digestion method

Tomatoes are an important source of antioxidant compounds, such as lycopene, phenolics and ascorbic acid. The main objective of this study was to determine the accessibility (availability for absorption) of the antioxidant compounds (total phenolics, total flavonoids, lycopene, ascorbic acid) and the antioxidant activity in fresh tomatoes of three cultivars (Excell, Tradiro and Flavourine) grown in New Zealand. The tomatoes were subjected to an in vitro digestion method, in which the pH, temperature, enzymes and chemical conditions were maintained according to human gastrointestinal conditions. The results showed that a high amount of the total phenolics and total flavonoids (71-77%) were released from tomatoes during digestion. However, only 3.2-4.5% of the total lycopene was released. No ascorbic acid could be detected after completion of in vitro digestion, probably due to degradation. After completion of digestion, the in vitro digestion extracts were found to have 45-50% antioxidant activity compared with the total antioxidant activity of fresh tomatoes (as measured by the 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid diammonium salt radical decolourization assay). This study shows that the antioxidant components of tomatoes were affected by the in vitro digestion conditions depending on the type of compound. This in vitro digestion method gives an estimate of the release of antioxidant components in tomato, which may predict their in vivo behaviour.     

Free radical scavenger and antioxidant capacity correlation of alpha-tocopherol and Trolox measured by three in vitro methodologies

The objective of this study was to correlate the free radical scavenging and antioxidant activity of two known substances (Trolox and alpha-tocopherol), using three in vitro methods (linoleic acid emulsion, brain homogenate and 2,2-diphenyl-1-picryl-hydrazyl [DPPH]). At steady state, alpha-tocopherol showed a greater inhibition of spontaneous oxidation of brain homogenate (59.42%+/-1.91) than Trolox (38.50%+/-2.38), while the latter showed a better antioxidant activity performance regarding inhibition of linoleic acid peroxidation (100% versus 84.02%+/-1.98) and free radical scavenging activity (93.56%+/-5.71 versus 66.72%+/-6.28). When the IC50 value was used as a parameter, alpha-tocopherol presented greater antioxidant activity than Trolox evaluated in brain homogenate and DPPH, without a significant difference when using linoleic acid emulsion. Both compounds showed the same antioxidant efficiency measured by DPPH kinetics (0.37 mM). Antioxidant activity significantly changed according to the substrate, the parameter adopted to compare the substances in the same method and the form used to express antioxidant concentration.     

Influence of storage and in vitro gastrointestinal digestion on total antioxidant capacity of fruit beverages

Eight fruit beverages containing grape, orange and apricot, with/without iron and/or zinc and with/without milk added were analyzed for total antioxidant capacity (ORAC and TEAC methods), ascorbic acid content, and total polyphenols. The influence of cold storage (2-4 °C) during the product shelf-life (135 days) and antioxidant capacity after an in vitro gastrointestinal digestion were evaluated. Antioxidant capacity for all beverages together increased significantly (p < 0.05) at the end of storage (16.4% and 12.8% for ORAC and TEAC, respectively), whereas ascorbic acid remained stable. Regarding in vitro digestion, antioxidant values of bioaccessible fractions of fruit beverages increased (p < 0.05) 59% and 20% for ORAC and TEAC, respectively, while ascorbic acid and polyphenol content fell 36% and 16%, respectively (p < 0.05). Supplementation of fruit beverages with milk and/or Fe/Zn did not modify total antioxidant capacity of samples during either cold storage or during in vitro digestion.     

Radical-scavenging activity of hot water extract of Japanese rice bran--association with phenolic acids

A strong radical-scavenging activity against a stable radical compound, 1,1-diphenyl-2-picrylhydrazyl (DPPH) was found in the hot water extract of Japanese rice bran. When the extract was treated with ethanol, a dominant radical-scavenging activity was observed in the ethanol-soluble (ES) fraction in a dose-dependent manner, but a weak radical-scavenging activity was detected in the ethanol-precipitable (EP) fraction. Their activities were proportional to the amounts of phenolic substances in each fraction. The phenolic substances in the ES fraction were efficiently separated by Amberlite XAD column chromatography and high performance liquid chromatography using an ODS column. The four major phenolic acids (ferulic, para-coumaric, para-hydroxybenzoic and vanillic acids) and four minor phenolic acids (caffeic, gentisic, protocatechuic and syringic acids) were detected in the HPLC system. Among these phenolic acids, protocatechuic, caffeic, ferulic and gentisic acids showed relatively strong radical scavenging activities (EC50: 8, 9, 29 and 75 microM, respectively) compared with the control antioxidants such as ascorbic acid and alpha-tocopherol (EC50: 93 and 134 microM). Para-coumaric, syringic and vanillic acids exhibited weak but significant radical-scavenging activities (EC50: 780, 2640 and 3250 microM). However, para-hydroxybenzoic acid did not show any significant effects even at 5 mM. Furthermore, a simulated mixture combined with these phenolic acids in comparable amounts in the ES fraction showed slightly weak radical-scavenging activity compared with that of rice bran extract. However, all the phenolic acids detected in the ES fraction did not show significant antioxidant activities against hydroperoxide generation in lipid peroxidation compared with that of a typical antioxidant such as ascorbic acid, which was estimated by the alminum chloride method. These results suggest that Japanese rice bran has a potent radical-scavenging activity against DPPH radical and this activity is associated with some phenolic acids in the ES fraction. The significance of this finding is discussed from the viewpoint of the protective role of rice bran against oxygen radical-induced chronic diseases.     

蛋清蛋白肽体外血管紧张素转化酶抑制活性及其消化稳定性

目的研究蛋清蛋白肽体外血管紧张素转化酶(ACE)抑制活性以及耐胃肠道消化稳定性。方法采用超滤分离蛋清蛋白酶解产物;利用高效液相色谱法测定蛋白酶水解物及其超滤各组分的体外ACE抑制活性。氨基酸自动分析仪测定ACE抑制活性较高组分(EWPH-Ⅲ)的氨基酸组成。体外模拟胃肠道消化试验测定EWPH-Ⅲ的消化稳定性。RP-HPLC法分析消化产物的组成变化。结果蛋清蛋白水解物的ACE抑制活性随着分子量的降低而增强(P<0.05),分子量小于3ku组分(EWPH-Ⅲ)的ACE抑制效果最好,其IC50值为0.049 mg/ml。EWPH-Ⅲ中疏水性氨基酸和必需氨基酸总量分别为49.51%和50.26%。经过胃肠道消化作用后,EWPH-Ⅲ的ACE抑制活性有所降低,消化产物的RP-HPLC分析结果显示EWPH-Ⅲ中多肽组分发生了明显的变化,胰酶消化产物中疏水性较强的多肽组分含量有所减少。结论蛋清蛋白肽具有较强的ACE抑制活性并且具有很高的营养价值,其ACE抑制活性随着阶段性的胃肠道消化而发生改变。     

Antioxidant peptide isolated from muscle protein of bullfrog, Rana catesbeiana Shaw

Bullfrog (Rana catesbeiana Shaw) muscle protein was enzymatically hydrolyzed for extraction of an antioxidant peptide. Antioxidant peptide from bullfrog muscle protein hydrolysate (APBMH) was purified using consecutive chromatographic methods, and the amino acid sequence was identified as being Leu-Glu-Gln-Gln-Val-Asp-Asp-Leu-Glu-Gly-Ser-Leu-Glu-Gln-Glu-Lys-Lys (molecular mass of 1,988 Da) by quantitative time-of-flight electrospray ionization mass spectroscopy. To assess antioxidant activities of APBMH, two different in vitro systems were employed: free radical scavenging activity by electron spin resonance (ESR) spectroscopy and polyunsaturated fatty acid (PUFA) peroxidation inhibition assay. ESR revealed that APBMH is an effective free radial scavenger with activity similar to that of vitamin C against 1,1-diphenyl-2-picrylhydrazyl, hydroxyl, and superoxide radicals, and its 50% inhibitory concentration values were 179.4 microM, 162.7 microM, and 176.1 microM, respectively. APBMH also significantly retarded PUFA oxidation, and more potently than did alpha-tocopherol, which was used as a positive control. In addition, the ability of APBMH to inhibit the oxidative damage of DNA was assessed, in vitro, by measuring the conversion of supercoiled pBR322 plasmid DNA to the open circular form. It was found that APBMH significantly protected hydroxyl radical-induced DNA damage dose-dependently.     

The antioxidant and radical scavenging activities of black pepper (Piper nigrum) seeds

Water and ethanol crude extracts from black pepper (Piper nigrum) were investigated for their antioxidant and radical scavenging activities in six different assay, namely, total antioxidant activity, reducing power, 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, and metal chelating activities. Both water extract (WEBP) and ethanol extract (EEBP) of black pepper exhibited strong total antioxidant activity. The 75 microg/ml concentration of WEBP and EEBP showed 95.5% and 93.3% inhibition on peroxidation of linoleic acid emulsion, respectively. On the other hand, at the same concentration, standard antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and alpha-tocopherol exhibited 92.1%, 95.0%, and 70.4% inhibition on peroxidation of linoleic acid emulsion, respectively. Also, total phenolic content in both WEBP and EEBP were determined as gallic acid equivalents. The total phenolics content of water and ethanol extracts were determined by the Folin-Ciocalteu procedure and 54.3 and 42.8 microg gallic acid equivalent of phenols was detected in 1 mg WEBP and EEBP.     

Bioactivity of Cooked Standard and Enriched Whole Eggs from White Leghorn and Rhode Island Red in Exhibiting In-Vitro Antioxidant and ACE-Inhibitory Effects

Hen breed, diet enrichment, cooking methods, and gastrointestinal (GI) digestion modulates the bioaccessibility of the bioactive compounds in eggs, but their synergistic role in modulating bioactivity is still unclear. The present study evaluates the effect of hen breed, diet enrichment, and GI digestion on the cooked whole egg-derived peptides in-vitro antioxidant and antihypertensive activities. Standard and enriched whole eggs from White Leghorn (WLH) and Rhode Island Red (RIR) hens were boiled or fried and subjected to GI digestion. Antioxidant activity was measured through oxygen radical absorbance capacity (ORAC) and gastrointestinal epithelial cell-based assays, and the antihypertensive capacity by in-vitro Angiotensin-I Converting Enzyme (ACE) inhibition assay. WLH fried standard egg hydrolysate showed a high ORAC antioxidant activity but failed to show any significant antioxidant effect in the cell-based assay. No significant differences were observed in the antihypertensive activity, although enriched samples tended to have a higher ACE-inhibitory capacity. The peptide profile explained the antioxidant capacities based on antioxidant structural requirements from different peptide fractions, while previously reported antihypertensive peptides were found in all samples. The study validates the importance of physiologically relevant models and requires future studies to confirm mechanisms that yield bioactive compounds in whole egg hydrolysates.     

The antioxidant and radical scavenging activities of black pepper (Piper nigrum) seeds

Water and ethanol crude extracts from black pepper (Piper nigrum) were investigated for their antioxidant and radical scavenging activities in six different assay, namely, total antioxidant activity, reducing power, 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, and metal chelating activities. Both water extract (WEBP) and ethanol extract (EEBP) of black pepper exhibited strong total antioxidant activity. The 75?µg/ml concentration of WEBP and EEBP showed 95.5% and 93.3% inhibition on peroxidation of linoleic acid emulsion, respectively. On the other hand, at the same concentration, standard antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and α-tocopherol exhibited 92.1%, 95.0%, and 70.4% inhibition on peroxidation of linoleic acid emulsion, respectively. Also, total phenolic content in both WEBP and EEBP were determined as gallic acid equivalents. The total phenolics content of water and ethanol extracts were determined by the Folin-Ciocalteu procedure and 54.3 and 42.8?µg gallic acid equivalent of phenols was detected in 1?mg WEBP and EEBP.     

Ascorbic acid does not increase the oxidative stress induced by dietary iron in C3H mice

Iron is a potent prooxidant that can induce lipid peroxidation. Ascorbic acid, a potent antioxidant, has prooxidant effects in the presence of iron in vitro. We investigated whether ascorbic acid and iron co-supplementation in ascorbic acid-sufficient mice increases hepatic oxidative stress. C3H/He mice were fed diets supplemented with iron to 100 mg/kg diet or 300 mg/kg diet with or without ascorbic acid (15 g/kg diet) for 3 wk. Liver iron concentration, malondialdehyde (MDA), glutathione (GSH), glutathione S-transferase (GST), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) were measured. High dietary iron increased liver iron concentrations slightly (P < 0.05), whereas it dramatically increased hepatic MDA (P < 0.0001). Ascorbic acid increased MDA but only in mice fed the low-iron diet (P < 0.05). The high-iron diet reduced GPx (P < 0.0001), CAT (P < 0.0005), SOD (P < 0.05), and GST (P < 0.005) activities regardless of ascorbic acid supplementation. In contrast, ascorbic acid reduced GPx (P < 0.0001) and CAT (P < 0.05) activities only in mice fed the low-iron diet. In conclusion, ascorbic acid supplementation can have prooxidant effects in the liver. However, ascorbic acid does not further increase the oxidative stress induced by increased dietary iron.     

大豆蛋白体外酶解物中血管紧张素转化酶抑制剂活性肽研究

目的:体外模仿部分胃肠道消化酶解过程,考察大豆蛋白酶解消化能否产生血管紧张素转化酶抑制剂(ACEI)活性肽及其活性状况,以揭示大豆蛋白体内消化酶解与ACEI的活性关系。方法:模拟人体胃肠道消化过程,以胃蛋白酶结合胰蛋白酶,相继酶解大豆分离蛋白(SPI),经色谱分离,动态检测不同阶段ACEI肽片段及其活性大小。结果:胃蛋白酶酶解过程前20min内,酶解液ACEI活性达到最高点,随后在胰蛋白酶酶解阶段其抑制活性下降。180min后的酶解产物,其半抑制活性浓度IC50值为0.28±0.06 mg/ml。同时,未经酶解的SPI液在0.73mg/ml时无ACEI活性。SPI酶解液经各种色谱分离后的组分,其IC50值从0.13±0.03到0.93±0.08 mg/ml。低分子量和伴有疏水性基团的肽类最具ACE抑制活性。结论:体外模仿胃肠消化过程使用胃蛋白酶和胰蛋白酶酶解SPI可产生不同ACEI活性的肽片段,说明人体正常摄食消化大豆蛋白可产生血管紧张素转化酶抑制剂活性肽。     

Phenolic compounds and biological activity of Kitaibelia vitifolia

This study was aimed at evaluating the antioxidant activity and efficacy of the ethanolic extract of the endemic plant species Kitaibelia vitifolia in inhibiting the growth of selected fungi and bacteria. Antimicrobial activity was tested using the broth dilution procedure for determination of minimum inhibitory concentration (MIC). MICs were determined for eight selected indicator strains. The highest susceptibility to K. vitifolia ethanolic extract among the bacteria tested was exhibited by Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 25923, and Klebsiella pneumoniae ATCC 13883 (MIC=15.62 μg/mL), followed by Escherichia coli ATCC 25922 and Proteus mirabilis ATCC 14153 (MIC=31.25 μg/mL), and Proteus vulgaris ATCC 13315 (MIC=62.50 μg/mL). Of the fungi, Candida albicans ATCC 10231 (MIC=15.62 μg/mL) showed the highest susceptibility, and Aspergillus niger ATCC 16404 (MIC=31.25 μg/mL) had the lowest. Results showed that K. vitifolia extract possesses antioxidant activity, with total antioxidant capacity of 75.45±0.68 μg of ascorbic acid/g and 50% inhibition concentration values of 47.45±0.55 μg/mL for 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity, 35.35±0.68?μg/mL for inhibitory activity against lipid peroxidation, 95.25±0.52 μg/mL for hydroxyl radical scavenging activity, and 31.50±0.35 μg/mL for metal chelating activity. Total phenolics, flavonoids, condensed tannins, and gallotannins were 85.25±0.69 mg of gallic acid (GA)/g, 45.32±0.55 mg of rutin/g, 54.25±0.75 mg of GA/g, and 41.74±0.55 mg of GA/g, respectively. The phenolic composition of K. vitifolia extract was determined by high-performance liquid chromatography. Rosmarinic acid was found to be the dominant phenolic compound of the extract.     

In vitro antioxidant and free radical scavenging activity of Cyperus rotundus

Cyperus rotundus (Family Cyperaceae) is used both as a functional food and as a drug. In this study, the antioxidative potential of a hydroalcoholic extract of C. rotundus (CRE) was evaluated by various antioxidant assays, including antioxidant capacity by the phosphomolybdenum method, total antioxidant activity in linoleic acid emulsion systems, 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide, hydroxyl radicals, and nitric oxide (NO) scavenging. We further evaluated the reducing potential of the extract as well as Fe(2+)/ascorbate-induced lipid peroxidation in rat liver homogenate. These various antioxidant activities were compared to standard antioxidants such as butylated hydroxytoluene, tocopherol, L-ascorbic acid, and catechin. Total phenolic and flavonoid content of CRE was also determined by a colorimetric method. The extract exhibited high reduction capability and powerful free radical scavenging, especially against DPPH and superoxide anions as well as a moderate effect on NO. CRE also showed inhibited lipid peroxidation in rat liver homogenate induced by Fe(2+)/ascorbate and prevented deoxyribose degradation in both non-site-specific and site-specific assays showing the hydroxyl radical scavenging and metal chelating activity of the hydroalcoholic extract. Moreover, the peroxidation inhibiting activity of CRE was demonstrated in the linoleic acid emulsion system. These results clearly established the antioxidative potency of C. rotundus, which may account for some of the medical claims attributed to this plant.     

Antioxidant activity, ascorbic acid and total phenol of exotic fruits occurring in Brazil

The antioxidant activity, ascorbic acid and phenolic content were studied in 10 exotic fruits from Brazil: abiu, acerola, wax jambu, cashew, mamey sapote, carambola or star fruit, Surinam cherry, longan, sapodilla and jaboticaba. The ascorbic acid was determined by 2,6-dichloroindophenol titrimetic methods and total phenols were measured colorimetrically using the Folin-Ciocalteu reagent. The antioxidant activity was investigated with three different methods: hypochlorous acid scavenging activity, 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation decolorization assay, and 2,2-diphenyl-1-picrylhydrazyl radical scavenging method. The highest content of vitamin C (1,525.00 mg/100 g pulp) occurred in acerola. The total phenol content was higher in abiu, acerola, Surinam cherry and sapodilla. In relation to antioxidant activity, acerola has showed the great values in all three different methods tested. It was found that the fruits have a significant antioxidant effect when tested by each method, respectively, and these antioxidant capacities are promising. The sample concentration also influenced its antioxidant power.     

Interaction between ascorbic acid and acetylsalicylic acid and their effects on nutritional status in man

Healthy adults were given four diets, each one for one week: Low ascorbic acid diet, low ascorbic acid diet plus acetylsalicylic acid (3 g/d), high ascorbic acid diet (1 g/d) and high ascorbic acid diet plus acetylsalicylic acid. At low ascorbic acid intake, acetylsalicylic acid increased urinary ascorbic acid, but at high ascorbic acid intake, acetylsalicylic acid instead decreased urinary ascorbic acid. The latter effect was probably due to an inhibited intestinal absorbtion of ascorbic acid, and the former effect may reflect decreased protein binding and tissue uptake of ascorbic acid caused by acetylsalicylic acid. In no instance, acetylsalicylic acid affected plasma ascorbic acid. The effect of ascorbic acid on substances related to lipid peroxidation was investigated. The high ascorbic acid diets decreased plasma lipoperoxide and retinol binding protein. No change was observed in serum tocopherol, iron status, erythrocyte lipid fluorescence, plasma ceruloplasmin, urinary and plasma selenium and glutathione peroxidase activity. Thus, one-week supplementation of ascorbic acid seems to have only marginal effects on lipid peroxidation and antioxidant status.     

Hypolipidemic and Antioxidative Effects of Aqueous Enzymatic Extract from Rice Bran in Rats Fed a High-Fat and -Cholesterol Diet

Purpose: The aqueous enzymatic extract from rice bran (AEERB) was rich in protein, γ-oryzanol and tocols. The aim of this study was to investigate the effects of AEERB on the regulation of lipid metabolism and the inhibition of oxidative damage. Methods: The antioxidant activity of AEERB in vitro was measured in terms of radical scavenging capacity, ferric reducing ability power (FRAP) and linoleic acid emulsion system-ferric thiocyanate method (FTC). Male Wistar rats were fed with a normal diet and a high-fat and high-cholesterol diet with or without AEERB. After treatment, biochemical assays of serum, liver and feces lipid levels, the antioxidant enzyme activity, malondialdehyde (MDA) and protein carbonyl were determined. Result: AEERB is completely soluble in water and rich in hydrophilic and lipophilic functional ingredients. AEERB scavenged DPPH• and ABTS^•+ and exhibited antioxidant activity slightly lower than that of ascorbic acid in the linoleic acid system. The administration of AEERB reduced serum lipid levels and the atherogenic index compared with those of the hyperlipidemic diet group (HD). The administration of AEERB significantly lowered liver lipid levels, inhibited hepatic 3-hydroxyl-3-methylglutaryl CoA reductase activity, and efficiently promoted the fecal excretion of total lipids and total cholesterol (TC) (p < 0.05). Dietary AEERB enhanced antioxidant status in the serum, liver and brain by increasing the antioxidant enzyme activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) and decreasing the content of MDA and protein carbonyl. Conclusions: The results indicated that AEERB might act as a potent hypolipidemic and antioxidant functional food.     

Antioxidant Activities and Total Phenolic Content of Aqueous Extract of Pleurotus ostreatus (Cultivated Oyster Mushroom)

Pleurotus ostreatus better known as oyster mushroom is widely cultivated and consumed as food in Malaysia. The present study aims to assess the antioxidative potential and total phenolic content of P. ostreatus aqueous extract. The antioxidant activities were evaluated against DPPH and ABTS radical-scavenging activity, ferric-reducing antioxidant power (FRAP) and β-carotene-linoleate bleaching assay, and the Folin-Ciocalteu method for total phenolic content (TPC). The DPPH and ABTS radical-scavenging activity was found to be 63.20% and 87.29% respectively; antioxidant activity using FRAP at 1.45 mM FE/100g and β-carotenelinoleate bleaching assay was 83.51%, while the TPC was found to be 798.55 mg GAE/100g. These antioxidant activities were compared to synthetic antioxidant, BHA and ascorbic acid. Ascorbic acid showed highest scavenging effects on DPPH and ABTS radical, followed by P. ostreatus and BHA (at maximum safety limit). The ferric reducing power of P. ostreatus was significantly higher than BHA and ascorbic acid. The antioxidant activity as assessed in β-carotene-linoleate bleaching assay was found to be higher in BHA compared to P. ostreatus. The aqueous extract of P. ostreatus was found to respond differently in antioxidant assays. The antioxidative activity of the aqueous extract of P. ostreatus correlated with its total phenolic content. Generally, the antioxidant activities of P. ostreatus' aqueous extract are comparable to that of BHA and ascorbic acid to a certain extent.     

Antioxidant activity of methanolic extract of emblica fruit (Phyllanthus emblica L.) from six regions in China

The phenolic contents of methanolic extracts of emblica (Phyllanthus emblica L.) fruit from six regions in China were measured in this work. The antioxidant activities of these extracts were also evaluated. Total phenolic content was ranged from 81.5 to 120.9 mg gallic acid equivalents (GAE)/g and the flavonoid content was varied from 20.3 to 38.7 mg quecetin equivalents (QE)/g, while proanthocyanidin content was ranged from 3.7 to 18.7 mg catechin equivalents (CE)/g. Among all the methanolic extracts analyzed, the Huizhou sample exhibited a significantly higher phenolic content than other samples (P<0.05). The antioxidant activities were evaluated by in vitro experiments using scavenging assays of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, hydroxyl radicals, and superoxide anion radicals, chelating ability of ferrous ion, reducing power, and inhibition capability of Fe (II)-induced lipid peroxidation, respectively. The Huizhou sample was found to have the strongest antioxidant activities in scavenging DPPH radicals, superoxide anion radicals, and had the highest reducing power, while the Chuxiong sample showed the best performance in chelating iron and inhibiting lipid peroxidation. Furthermore, the Chuxiong sample exhibited a stronger inhibition activity of the hydroxyl radicals compared with other samples. The high correlation coefficient was existed between the phenolic content and superoxide anion radical scavenging activity, but no significant correlation was found between the former and hydroxyl radical scavenging activity. Methanolic extracts of emblica fruit from some selected regions exhibited stronger antioxidant activities compared to those of the commercial compounds (quercetin and BHA). It might be considered as a potential plant source of antioxidants.     

Bioconversion of grape and chokeberry wine polyphenols during simulated gastrointestinal in vitro digestion

The primary objective of the present study was to assess the qualitative and quantitative changes of wine polyphenols during in vitro digestion process conducted in a gastrointestinal tract model. Wines selected for these experiments were red grape, white grape and chokeberry wines. Following the stages of in vitro digestion-stomach, small and large intestine-qualitative and quantitative changes particularly in phenolic acids were monitored. Decomposition of resveratrol and chlorogenic acid, secretion of caffeic acid and formation of other derivatives characterized with high antioxidant activity were determined. As a second focus of this work the evaluation of interactions between human fecal microflora (Enterobacteriaceae, Lactobacillus, Enterococcus and Bifidobacterium) and polyphenolic compounds and their derivatives secreted during the digestion were performed.     

Antioxidant capacity of crude extracts from clones of banana and plane species

Banana and plane are the most important fruits in world trade, behind citric plants. In this work we studied the antioxidant capacity of banana and plane varieties of fruits obtained from interspecies crossed varieties of Musa acuminata and Musa balbisiana, named Harton plane, Cavendish banana, and Manzano banana. With this purpose we evaluated banana and plane crude extracts using the ferrous ion oxidation with xylenol orange method, the thiobarbituric acid method, determination of antioxidant activity, and effect on superoxide anion and hydroxyl radical and the radicals generated by ultraviolet light. The experiments showed that all extracts have the capacity to decrease the concentrations of lipid hydroperoxides and malondialdehyde, produced in the lipid peroxidation process, in a manner comparable to that of other widely studied antioxidants like melatonin and vitamin E. Moreover, all extracts had the capacity to inhibit the generation of superoxide anion, hydroxyl radical, and the radicals generated by ultraviolet light. When antioxidant activity was calculated, a value was found that was equivalent to a concentration of uric acid between 0.20 and 0.30 mM at the highest concentration of extract used, with uric acid being a potent antioxidant at 1 mM.