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Special Issue "Antioxidants"

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A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Biochemistry, Molecular Biology and Biophysics".

Deadline for manuscript submissions: closed (15 December 2011)

Special Issue Editor

Guest Editor
Prof. Dr. Michael H. Gordon

Department of Food and Nutritional Sciences, University of Reading, Whiteknights PO Box 226, Reading RG6 6AP, UK
E-Mail
Phone: 441183786723
Fax: +44118 3787708
Interests: antioxidants in food; antioxidant mechanisms; food chemistry; phytochemicals; bioavailability of antioxidants

Special Issue Information

Dear Colleagues,

The subject of antioxidants has developed by leaps and bounds since the studies in the late 19th and early 20th centuries into the compounds that could retard or prevent the effects of oxidation of industrial polymers such as rubber and the mechanisms of their action. The subject was given a strong boost in the mid 20th century when it was realised that the deterioration of lipid-containing foods could be retarded by the use of antioxidants, and again in the late 20th century, when the importance of radical reactions in the degradation of biological molecules and the significance for human health was recognised. Although it is now recognised that phytochemicals have a range of bioactivities including effects on cell signalling and gene expression, the bioavailability, activity, and effects of antioxidants on physiological processes continues to be an important area of study. The topic of antioxidants also remains an important subject for research in the optimisation of the stability of a range of industrial products and foods. The development of natural antioxidants to allow food manufacturers to replace synthetic antioxidants, the activity of antioxidants in polymers such as food packaging, and migration of the antioxidants from polymers into liquids in contact with them are other important areas. This special issue contains a range of papers reporting some of the interesting developments in this area.

Prof. Dr. Mike Gordon
Guest Editor

Keywords

  • antioxidants
  • activity
  • bioavailability
  • food
  • health
  • mechanisms
  • nutrition
  • packaging
  • polymers

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Published Papers (18 papers)

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Open AccessArticle Extracts of Phenolic Compounds from Seeds of Three Wild Grapevines—Comparison of Their Antioxidant Activities and the Content of Phenolic Compounds
Int. J. Mol. Sci. 2012, 13(3), 3444-3457; doi:10.3390/ijms13033444
Received: 8 December 2011 / Revised: 29 February 2012 / Accepted: 1 March 2012 / Published: 13 March 2012
Cited by 18 | PDF Full-text (396 KB) | HTML Full-text | XML Full-text
Abstract
Phenolic compounds were extracted from three wild grapevine species: Vitis californica, V. riparia and V. amurensis seeds using 80% methanol or 80% acetone. The total content of phenolic compounds was determined utilizing the Folin-Ciocalteu’s phenol reagent while the content of tannins was
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Phenolic compounds were extracted from three wild grapevine species: Vitis californica, V. riparia and V. amurensis seeds using 80% methanol or 80% acetone. The total content of phenolic compounds was determined utilizing the Folin-Ciocalteu’s phenol reagent while the content of tannins was assayed with the vanillin and BSA precipitation methods. Additionally, the DPPH free radical scavenging activity and the reduction power of the extracts were measured. The RP-HPLC method was applied to identify the phenolic compounds in the extracts, such as phenolic acids and catechins. The seeds contained large amounts of tannins, catechins and gallic acid and observable quantities of p-coumaric acid. The total content of phenolic compounds and tannins was similar in the extracts from V. californica and V. riparia seeds. However, the total content of total phenolic compounds and tannins in the extracts from V. californica and V. riperia seeds were about two-fold higher than that in the extracts from V. amurensis seeds. Extracts from seeds of the American species (V. californica and V. riparia) contained similarly high concentrations of tannins, whereas extracts from seeds of V. amurensis had approximately half that amount of these compounds. The content of catechin and epicatechin was similar in all extracts. The highest DPPH anti-radical scavenging activity was observed in the acetonic and methanolic extracts of V. californica and V. riparia seeds—while the acetonic extract from the V. californica seeds was the strongest reducing agent. Full article
(This article belongs to the Special Issue Antioxidants)
Open AccessArticle Antioxidant Activity of Mulberry Fruit Extracts
Int. J. Mol. Sci. 2012, 13(2), 2472-2480; doi:10.3390/ijms13022472
Received: 13 December 2011 / Revised: 16 February 2012 / Accepted: 16 February 2012 / Published: 22 February 2012
Cited by 26 | PDF Full-text (150 KB) | HTML Full-text | XML Full-text
Abstract
Phenolic compounds were extracted from the fruits of Morus nigra and Morus alba using methanol and acetone. The sugar-free extracts (SFEs) were prepared using Amberlite XAD-16 column chromatography. All of the SFEs exhibited antioxidant potential as determined by ABTS (0.75–1.25 mmol Trolox/g), DPPH
[...] Read more.
Phenolic compounds were extracted from the fruits of Morus nigra and Morus alba using methanol and acetone. The sugar-free extracts (SFEs) were prepared using Amberlite XAD-16 column chromatography. All of the SFEs exhibited antioxidant potential as determined by ABTS (0.75–1.25 mmol Trolox/g), DPPH (2,2-diphenyl-1-picrylhydrazyl) (EC50 from 48 μg/mL to 79 μg/mL), and reducing power assays. However, a stronger activity was noted for the SFEs obtained from Morus nigra fruits. These extracts also possessed the highest contents of total phenolics: 164 mg/g (methanolic SFE) and 173 mg/g (acetonic SFE). The presence of phenolic acids and flavonoids in the extracts was confirmed using HPLC method and chlorogenic acid and rutin were found as the dominant phenolic constituents in the SFEs. Full article
(This article belongs to the Special Issue Antioxidants)
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Open AccessArticle Emodin Prevents Intrahepatic Fat Accumulation, Inflammation and Redox Status Imbalance During Diet-Induced Hepatosteatosis in Rats
Int. J. Mol. Sci. 2012, 13(2), 2276-2289; doi:10.3390/ijms13022276
Received: 9 January 2012 / Revised: 7 February 2012 / Accepted: 9 February 2012 / Published: 20 February 2012
Cited by 17 | PDF Full-text (725 KB) | HTML Full-text | XML Full-text
Abstract
High-fat and/or high-carbohydrate diets may predispose to several metabolic disturbances including liver fatty infiltration (hepatosteatosis) or be associated with necro-inflammation and fibrosis (steatohepatitis). Several studies have emphasized the hepatoprotective effect of some natural agents. In this study, we investigated the potential therapeutic effects
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High-fat and/or high-carbohydrate diets may predispose to several metabolic disturbances including liver fatty infiltration (hepatosteatosis) or be associated with necro-inflammation and fibrosis (steatohepatitis). Several studies have emphasized the hepatoprotective effect of some natural agents. In this study, we investigated the potential therapeutic effects of the treatment with emodin, an anthraquinone derivative with anti-oxidant and anti-cancer abilities, in rats developing diet-induced hepatosteatosis and steatohepatitis. Sprague-Dawley rats were fed a standard diet (SD) for 15 weeks, or a high-fat/high-fructose diet (HFD/HF). After 5 weeks, emodin was added to the drinking water of some of the SD and HFD/HF rats. The experiment ended after an additional 10 weeks. Emodin-treated HFD/HF rats were protected from hepatosteatosis and metabolic derangements usually observed in HFD/HF animals. Furthermore, emodin exerted anti-inflammatory activity by inhibiting the HFD/HF-induced increase of tumor necrosis factor (TNF)-α. Emodin also affected the hepatocytes glutathione homeostasis and levels of the HFD/HF-induced increase of glutathionylated/phosphorylated phosphatase and tensin homolog (PTEN). In conclusion, we demonstrated that a natural agent such as emodin can prevent hepatosteatosis, preserving liver from pro-inflammatory and pro-oxidant damage caused by HFD/HF diet. These findings are promising, proposing emodin as a possible hindrance to progression of hepatosteatosis into steatohepatitis. Full article
(This article belongs to the Special Issue Antioxidants)
Open AccessArticle 10-Shogaol, an Antioxidant from Zingiber officinale for Skin Cell Proliferation and Migration Enhancer
Int. J. Mol. Sci. 2012, 13(2), 1762-1777; doi:10.3390/ijms13021762
Received: 22 December 2011 / Revised: 9 January 2012 / Accepted: 13 January 2012 / Published: 8 February 2012
Cited by 18 | PDF Full-text (449 KB) | HTML Full-text | XML Full-text
Abstract
In this work, one of Zingiber officinale components, 10-shogaol, was tested with 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, metal chelating ability, and reducing power to show antioxidant activity. 10-Shogaol promoted human normal epidermal keratinocytes and dermal fibroblasts cell growths. 10-Shogaol enhanced growth factor production in
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In this work, one of Zingiber officinale components, 10-shogaol, was tested with 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, metal chelating ability, and reducing power to show antioxidant activity. 10-Shogaol promoted human normal epidermal keratinocytes and dermal fibroblasts cell growths. 10-Shogaol enhanced growth factor production in transforming growth factor-β (TGF-β), platelet derived growth factor-αβ (PDGF-αβ) and vascular endothelial growth factors (VEGF) of both cells. In the in vitro wound healing assay for 12 or 24 h, with 10-shogaol, the fibroblasts and keratinocytes migrated more rapidly than the vehicle control group. Thus, this study substantiates the target compound, 10-shogaol, as an antioxidant for human skin cell growth and a migration enhancer with potential to be a novel wound repair agent. Full article
(This article belongs to the Special Issue Antioxidants)
Open AccessArticle Lipid Peroxidative Damage on Cisplatin Exposure and Alterations in Antioxidant Defense System in Rat Kidneys: A Possible Protective Effect of Selenium
Int. J. Mol. Sci. 2012, 13(2), 1790-1803; doi:10.3390/ijms13021790
Received: 23 November 2011 / Revised: 23 January 2012 / Accepted: 31 January 2012 / Published: 8 February 2012
Cited by 32 | PDF Full-text (260 KB) | HTML Full-text | XML Full-text
Abstract
Cisplatin (Cis-diamminedichloroplatinum II, CP) is an important chemotherapeutic agent, useful in the treatment of several cancers, but with several side effects such as nephrotoxicity. The present study investigated the possible protective effect of selenium (Se) against CP-induced oxidative stress in the
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Cisplatin (Cis-diamminedichloroplatinum II, CP) is an important chemotherapeutic agent, useful in the treatment of several cancers, but with several side effects such as nephrotoxicity. The present study investigated the possible protective effect of selenium (Se) against CP-induced oxidative stress in the rat kidneys. Male Wistar albino rats were injected with a single dose of cisplatin (7 mg CP/kg b.m., i.p.) and selenium (6 mg Se/kg b.m, as Na2SeO3, i.p.), alone or in combination. The obtained results showed that CP increased lipid peroxidation (LPO) and decreased reduced glutathione (GSH) concentrations, suggesting the CP-induced oxidative stress, while Se treatment reversed this change to control values. Acute intoxication of rats with CP was followed by statistically significant decreased activity of antioxidant defense enzymes: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR) and glutathione-S-transferase (GST). Treatment with Se reversed CP-induced alterations of antioxidant defense enzyme activities and significantly prevented the CP-induced kidney damage. Full article
(This article belongs to the Special Issue Antioxidants)
Open AccessArticle Coenzyme Q Metabolism Is Disturbed in High Fat Diet-Induced Non Alcoholic Fatty Liver Disease in Rats
Int. J. Mol. Sci. 2012, 13(2), 1644-1657; doi:10.3390/ijms13021644
Received: 3 December 2011 / Revised: 12 January 2012 / Accepted: 29 January 2012 / Published: 2 February 2012
Cited by 5 | PDF Full-text (239 KB) | HTML Full-text | XML Full-text
Abstract
Oxidative stress is believed to be a major contributory factor in the development of non alcoholic fatty liver disease (NAFLD), the most common liver disorder worldwide. In this study, the effects of high fat diet-induced NAFLD on Coenzyme Q (CoQ) metabolism and plasma
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Oxidative stress is believed to be a major contributory factor in the development of non alcoholic fatty liver disease (NAFLD), the most common liver disorder worldwide. In this study, the effects of high fat diet-induced NAFLD on Coenzyme Q (CoQ) metabolism and plasma oxidative stress markers in rats were investigated. Rats were fed a standard low fat diet (control) or a high fat diet (57% metabolizable energy as fat) for 18 weeks. The concentrations of total (reduced + oxidized) CoQ9 were increased by > 2 fold in the plasma of animals fed the high fat diet, while those of total CoQ10 were unchanged. Reduced CoQ levels were raised, but oxidized CoQ levels were not, thus the proportion in the reduced form was increased by about 75%. A higher percentage of plasma CoQ9 as compared to CoQ10 was in the reduced form in both control and high fat fed rats. Plasma protein thiol (SH) levels were decreased in the high fat-fed rats as compared to the control group, but concentrations of lipid hydroperoxides and low density lipoprotein (LDL) conjugated dienes were unchanged. These results indicate that high fat diet-induced NAFLD in rats is associated with altered CoQ metabolism and increased protein, but not lipid, oxidative stress. Full article
(This article belongs to the Special Issue Antioxidants)
Open AccessArticle Effect of Byrsonima crassa and Phenolic Constituents on Helicobacter pylori-Induced Neutrophils Oxidative Burst
Int. J. Mol. Sci. 2012, 13(1), 133-141; doi:10.3390/ijms13010133
Received: 29 August 2011 / Revised: 28 November 2011 / Accepted: 13 December 2011 / Published: 23 December 2011
Cited by 6 | PDF Full-text (112 KB) | HTML Full-text | XML Full-text
Abstract
Byrsonima crassa Niedenzu (Malpighiaceae) is used in Brazilian folk medicine for the treatment of diseases related mainly to gastric ulcers. In a previous study, our group described the gastric protective effect of the methanolic extract from the leaves of B. crassa. The
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Byrsonima crassa Niedenzu (Malpighiaceae) is used in Brazilian folk medicine for the treatment of diseases related mainly to gastric ulcers. In a previous study, our group described the gastric protective effect of the methanolic extract from the leaves of B. crassa. The present study was carried out to investigate the effects of methanolic extract and its phenolic compounds on the respiratory burst of neutrophils stimulated by H. pylori using a luminol-based chemiluminescence assay as well as their anti-H. pylori activity. The suppressive activity on oxidative burst of H. pylori-stimulated neutrophils was in the order of methyl gallate > (+)-catechin > methanol extract > quercetin 3-O-α-l-arabinopyranoside > quercetin 3-O-β-d-galactopyranoside > amentoflavone. Methyl gallate, compound that induced the highest suppressive activity with IC50 value of 3.4 µg/mL, did not show anti-H. pylori activity. B. crassa could be considered as a potential source of natural antioxidant in gastric ulcers by attenuating the effects on the damage to gastric mucosa caused by neutrophil generated reactive oxygen species, even when H. pylori displays its evasion mechanisms. Full article
(This article belongs to the Special Issue Antioxidants)
Open AccessArticle Anti-UVC Irradiation and Metal Chelation Properties of 6-Benzoyl-5,7-dihydroxy-4-phenyl-chromen-2-one: An Implications for Anti-Cataract Agent
Int. J. Mol. Sci. 2011, 12(10), 7059-7076; doi:10.3390/ijms12107059
Received: 29 July 2011 / Revised: 23 September 2011 / Accepted: 11 October 2011 / Published: 21 October 2011
Cited by 2 | PDF Full-text (719 KB) | HTML Full-text | XML Full-text
Abstract
Coumarin derivative 1, 5,7-dihydroxy-6-(3-methyl-1-butyryl)-4-phenyl-chromen-2-one, has been reported to possess radical scavenging activity and DNA protection. We have synthesized a series of coumarins with structural modifications at positions C4, C5, C6 and C7 and evaluated them for their anti-UVC properties. Coumarin 7, 6-benzoyl-5,6-dihydroxy-4-phenyl-chromen-2-one, was
[...] Read more.
Coumarin derivative 1, 5,7-dihydroxy-6-(3-methyl-1-butyryl)-4-phenyl-chromen-2-one, has been reported to possess radical scavenging activity and DNA protection. We have synthesized a series of coumarins with structural modifications at positions C4, C5, C6 and C7 and evaluated them for their anti-UVC properties. Coumarin 7, 6-benzoyl-5,6-dihydroxy-4-phenyl-chromen-2-one, was found to have the most potent activity in protecting porcine γ-crystallin against UVC insults. Results of fluorescence assays indicated that compound 7 was capable of decreasing the loss of intensity while lens crystallins and DNA PUC19 were irradiated with UVC. Presence of compound 7 decreased hydroxyl radical levels determined by probe 1b and the free iron concentrations determined by Ferrozine reagent. The chelation assay showed that compound 7 was chelated to metal via 6-CO and 5-OH on the benzopyrone ring. The observed protective effects of compound 7 towards crystallins from insults of UVC and free radicals may be due to its iron-chelating activity and its peak absorption at 254 nm. Full article
(This article belongs to the Special Issue Antioxidants)
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Open AccessArticle N-Acetylcysteine Reduces Markers of Differentiation in 3T3-L1 Adipocytes
Int. J. Mol. Sci. 2011, 12(10), 6936-6951; doi:10.3390/ijms12106936
Received: 30 August 2011 / Accepted: 10 October 2011 / Published: 19 October 2011
Cited by 35 | PDF Full-text (268 KB) | HTML Full-text | XML Full-text
Abstract
Oxidative stress plays a critical role in the pathogenesis of diabetes, hypertension and atherosclerosis. Some authors reported that fat accumulation correlates to systemic oxidative stress in humans and mice, but the relationship of lipid production and oxidative metabolism is still unclear. In our
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Oxidative stress plays a critical role in the pathogenesis of diabetes, hypertension and atherosclerosis. Some authors reported that fat accumulation correlates to systemic oxidative stress in humans and mice, but the relationship of lipid production and oxidative metabolism is still unclear. In our laboratory we used 3T3-L1 preadipocytes, which are able to differentiate into mature adipocytes and accumulate lipids, as obesity model. We showed that intracellular reactive oxygen species (ROS) and antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities increased in parallel with fat accumulation. Meanwhile N-acetylcysteine (NAC), a well known antioxidant and Glutathione (GSH) precursor, inhibited ROS levels as well as fat accumulation in a concentration-dependent manner. NAC also inhibited both adipogenic transcription factors CCAAT/enhancer binding protein beta (C/EBP β) and peroxisomal proliferator activated receptor gamma (PPAR γ) expression; we suggested that intracellular GSH content could be responsible for these effects. Full article
(This article belongs to the Special Issue Antioxidants)
Open AccessArticle Antioxidant Properties of the Edible Basidiomycete Armillaria mellea in Submerged Cultures
Int. J. Mol. Sci. 2011, 12(10), 6367-6384; doi:10.3390/ijms12106367
Received: 10 August 2011 / Revised: 19 September 2011 / Accepted: 22 September 2011 / Published: 26 September 2011
Cited by 15 | PDF Full-text (575 KB) | HTML Full-text | XML Full-text
Abstract
Antioxidant components, ascorbic acid, total flavonoids and total phenols are produced effectively by Armillaria mellea submerged cultures. Dried mycelia and mycelia-free broths obtained by A. mellea submerged cultures are extracted with methanol and hot water and investigated for antioxidant properties. Methanolic extracts from
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Antioxidant components, ascorbic acid, total flavonoids and total phenols are produced effectively by Armillaria mellea submerged cultures. Dried mycelia and mycelia-free broths obtained by A. mellea submerged cultures are extracted with methanol and hot water and investigated for antioxidant properties. Methanolic extracts from dried mycelia (MEM) and mycelia-free broth (MEB) and hot water extracts from dried mycelia (HWEM) by A. mellea submerged cultures show good antioxidant properties as evidenced by low EC50 values (< 10 mg/mL). Total flavonoid is mainly found in hot water extracts; however, total phenol is rich in methanol and hot water extracts from mycelia. Ascorbic acid and total phenol contents are well correlated with the reducing power and the scavenging effect on superoxide anions. Total flavonoid content is dependent on the antioxidant activity and the chelating effect on ferrous ions. Total antioxidant component contents are closely related to the antioxidant activity and the scavenging superoxide anion ability. Results confirm that extracts with good antioxidant properties from fermenting products by A. mellea are potential good substitutes for synthetic antioxidants and can be applied to antioxidant-related functional food and pharmaceutical industries. Full article
(This article belongs to the Special Issue Antioxidants)
Open AccessArticle Different Impacts of Cardiovascular Risk Factors on Oxidative Stress
Int. J. Mol. Sci. 2011, 12(9), 6146-6163; doi:10.3390/ijms12096146
Received: 10 June 2011 / Revised: 1 September 2011 / Accepted: 7 September 2011 / Published: 20 September 2011
Cited by 12 | PDF Full-text (729 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The objective of the study was to evaluate oxidative stress (OS) status in subjects with different cardiovascular risk factors. With this in mind, we have studied three models of high cardiovascular risk: hypertension (HT) with and without metabolic syndrome, familial hypercholesterolemia (FH) and
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The objective of the study was to evaluate oxidative stress (OS) status in subjects with different cardiovascular risk factors. With this in mind, we have studied three models of high cardiovascular risk: hypertension (HT) with and without metabolic syndrome, familial hypercholesterolemia (FH) and familial combined hyperlipidemia (FCH) with and without insulin resistance. Oxidative stress markers (oxidized/reduced glutathione ratio, 8-oxo-deoxyguanosine and malondialdehide) together with the activity of antioxidant enzyme triad (superoxide dismutase, catalase, glutathione peroxidase) and activation of both pro-oxidant enzyme (NAPDH oxidase components) and AGTR1 genes, as well as antioxidant enzyme genes (CuZn-SOD, CAT, GPX1, GSR, GSS and TXN) were measured in mononuclear cells of controls (n = 20) and patients (n = 90) by assessing mRNA levels. Activity of some of these antioxidant enzymes was also tested. An increase in OS and pro-oxidant gene mRNA values was observed in patients compared to controls. The hypertensive group showed not only the highest OS values, but also the highest pro-oxidant activation compared to those observed in the other groups. In addition, in HT a significantly reduced antioxidant activity and mRNA induction of antioxidant genes were found when compared to controls and the other groups. In FH and FCH, the activation of pro-oxidant enzymes was also higher and antioxidant ones lower than in the control group, although it did not reach the values obtained in hypertensives. The thioredoxin system was more activated in patients as compared to controls, and the highest levels were in hypertensives. The increased oxidative status in the presence of cardiovascular risk factors is a consequence of both the activation of pro-oxidant mechanisms and the reduction of the antioxidant ones. The altered response of the main cytoplasmic antioxidant systems largely contributes to OS despite the apparent attempt of the thioredoxin system to control it. Full article
(This article belongs to the Special Issue Antioxidants)
Open AccessArticle Identification of a Protein with Antioxidant Activity that is Important for the Protection against Beer Ageing
Int. J. Mol. Sci. 2011, 12(9), 6089-6103; doi:10.3390/ijms12096089
Received: 16 August 2011 / Revised: 1 September 2011 / Accepted: 9 September 2011 / Published: 19 September 2011
Cited by 16 | PDF Full-text (477 KB) | HTML Full-text | XML Full-text
Abstract
This study was carried out with fresh Australian lager beer which was sampled directly off the production line, the same samples aged for 12 weeks at 30 °C, and the vintage beer which was kept at 20 °C for 5 years. Characteristic Australian
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This study was carried out with fresh Australian lager beer which was sampled directly off the production line, the same samples aged for 12 weeks at 30 °C, and the vintage beer which was kept at 20 °C for 5 years. Characteristic Australian lager flavour was maintained in the fresh and vintage beers but was lost in the aged beer. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and free thiol group labelling analyses of beer proteins found that this flavour stability correlated with the presence of an unknown 10 kilodaltons (kDa) protein with a higher level of free thiols. The protein was purified by size-exclusion chromatography, then peptide sequencing and database matching identified it as the barley lipid transfer protein (LTP1). Further characterisation using diphenylpicrylhydrazyl (DPPH) free radical scavenging and a Saccharomyces cerevisiae-based antioxidant screening assay demonstrated that the LTP1 protein was active in DPPH reduction and antioxidant activity. The absence of free thiol in the aged beer indicates that the thiol functional groups within the LTP1 protein were saturated and suggests that it is important in the flavour stability of beer by maintaining reduction capacity during the ageing process. Full article
(This article belongs to the Special Issue Antioxidants)
Open AccessArticle The Antioxidant Activity of New Coumarin Derivatives
Int. J. Mol. Sci. 2011, 12(9), 5747-5761; doi:10.3390/ijms12095747
Received: 12 July 2011 / Revised: 18 August 2011 / Accepted: 22 August 2011 / Published: 7 September 2011
Cited by 49 | PDF Full-text (691 KB) | HTML Full-text | XML Full-text
Abstract
The antioxidant activity of two synthesized coumarins namely, N-(4,7-dioxo-2-phenyl-1,3-oxazepin-3(2H,4H,7H)-yl)-2-(2-oxo-2H-chromen-4-yloxy)acetamide 5 and N-(4-oxo-2-phenylthiazolidin-3-yl)-2-(2-oxo-2H-chromen-4-yloxy)acetamide 6 were studied with the DPPH, hydrogen peroxide and nitric oxide radical methods and compared with the known antioxidant
[...] Read more.
The antioxidant activity of two synthesized coumarins namely, N-(4,7-dioxo-2-phenyl-1,3-oxazepin-3(2H,4H,7H)-yl)-2-(2-oxo-2H-chromen-4-yloxy)acetamide 5 and N-(4-oxo-2-phenylthiazolidin-3-yl)-2-(2-oxo-2H-chromen-4-yloxy)acetamide 6 were studied with the DPPH, hydrogen peroxide and nitric oxide radical methods and compared with the known antioxidant ascorbic acid. Compounds 5 and 6 were synthesized in a good yield from the addition reaction of maleic anhydride or mercaptoacetic acid to compound 4, namely N'-benzylidene-2-(2-oxo-2H-chromen-4-yloxy)acetohydrazide. Compound 4 was synthesized by the condensation of compound 3, namely 2-(2-oxo-2H-chromen-4-yloxy) acetohydrazide, with benzaldehyde. Compound 3, however, was synthesized from the addition of hydrazine to compound 2, namely ethyl 2-(2-oxo-2H-chromen-4-yloxy)acetate, which was synthesized from the reaction of ethyl bromoacetate with 4-hydroxycoumarin 1. Structures for the synthesized coumarins 26 are proposed on the basis of spectroscopic evidence. Full article
(This article belongs to the Special Issue Antioxidants)
Open AccessArticle Synthesis of Xylooligosaccharides of Daidzein and Their Anti-Oxidant and Anti-Allergic Activities
Int. J. Mol. Sci. 2011, 12(9), 5616-5625; doi:10.3390/ijms12095616
Received: 7 June 2011 / Revised: 17 August 2011 / Accepted: 18 August 2011 / Published: 31 August 2011
Cited by 7 | PDF Full-text (236 KB) | HTML Full-text | XML Full-text
Abstract
The biocatalytic synthesis of xylooligosaccharides of daidzein was investigated using cultured cells of Catharanthus roseus and Aspergillus sp. β-xylosidase. The cultured cells of C. roseus converted daidzein into its 4'-O-β-glucoside, 7-O-β-glucoside, and 7-O-β-primeveroside, which was a new
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The biocatalytic synthesis of xylooligosaccharides of daidzein was investigated using cultured cells of Catharanthus roseus and Aspergillus sp. β-xylosidase. The cultured cells of C. roseus converted daidzein into its 4'-O-β-glucoside, 7-O-β-glucoside, and 7-O-β-primeveroside, which was a new compound. The 7-O-β-primeveroside of daidzein was further xylosylated by Aspergillus sp. β-xylosidase to daidzein trisaccharide, i.e., 7-O-[6-O-(4-O-(β-D-xylopyranosyl))-β-D-xylopyranosyl]-β-D-glucopyranoside, which was a new compound. The 4'-O-β-glucoside, 7-O-β-glucoside, and 7-O-β-primeveroside of daidzein exerted DPPH free-radical scavenging and superoxide radical scavenging activity. On the other hand, 7-O-β-glucoside and 7-O-β-primeveroside of daidzein showed inhibitory effects on IgE antibody production. Full article
(This article belongs to the Special Issue Antioxidants)
Open AccessArticle Chemical Structures of 4-Oxo-Flavonoids in Relation to Inhibition of Oxidized Low-Density Lipoprotein (LDL)-Induced Vascular Endothelial Dysfunction
Int. J. Mol. Sci. 2011, 12(9), 5471-5489; doi:10.3390/ijms12095471
Received: 27 June 2011 / Revised: 15 August 2011 / Accepted: 17 August 2011 / Published: 26 August 2011
Cited by 25 | PDF Full-text (1025 KB) | HTML Full-text | XML Full-text
Abstract
Vascular endothelial dysfunction induced by oxidative stress has been demonstrated to be the initiation step of atherosclerosis (AS), and flavonoids may play an important role in AS prevention and therapy. Twenty-three flavonoids categorized into flavones, flavonols, isoflavones, and flavanones, all with 4-oxo-pyronenucleus, were
[...] Read more.
Vascular endothelial dysfunction induced by oxidative stress has been demonstrated to be the initiation step of atherosclerosis (AS), and flavonoids may play an important role in AS prevention and therapy. Twenty-three flavonoids categorized into flavones, flavonols, isoflavones, and flavanones, all with 4-oxo-pyronenucleus, were examined for what structural characteristics are required for the inhibitory effects on endothelial dysfunction induced by oxidized low-density lipoprotein (oxLDL). Human vascular endothelial cells EA.hy926 were pretreated with different 4-oxo-flavonoids for 2 hs, and then exposed to oxLDL for another 24 hs. Cell viability and the level of malondialdehyde (MDA), nitric oxide (NO) and soluble intercellular adhesion molecule-1 (sICAM-1) were measured, respectively. Then, correlation analysis and paired comparison were used to analyze the structure–activity relationships. Significant correlations were observed between the number of –OH moieties in total or in B-ring and the inhibitory effectson endothelial dysfunction. Furthermore, 3',4'-ortho-dihydroxyl on B-ring, 3-hydroxyl on C-ring and 2,3-double bondwere correlated closely to the inhibitory effects of flavonolson cell viability decrease and lipid peroxidation. 5,7-meta-dihydroxyl group on A-ring was crucial for the anti-inflammatory effects of flavones and isoflavones in endothelial cells. Moreover, the substituted position of B-ring on C3 rather than C2 was important for NO release. Additionally, hydroxylation at C6 position significantly attenuated the inhibitory effects of 4-oxo-flavonoids on endothelial dysfunction. Our findings indicated that the effective agents in inhibiting endothelial dysfunction include myricetin, quercetin, luteolin, apigenin, genistein and daidzein. Our work might provide some evidence for AS prevention and a strategy for the design of novel AS preventive agents. Full article
(This article belongs to the Special Issue Antioxidants)
Open AccessArticle Polyphenolic Contents and Antioxidant Potential of Stem Bark Extracts from Jatropha curcas (Linn)
Int. J. Mol. Sci. 2011, 12(5), 2958-2971; doi:10.3390/ijms12052958
Received: 7 March 2011 / Revised: 10 April 2011 / Accepted: 27 April 2011 / Published: 5 May 2011
Cited by 39 | PDF Full-text (331 KB) | HTML Full-text | XML Full-text
Abstract
We assessed the polyphenolic contents and antioxidant potential of the aqueous, ethanol and methanol stem bark extracts of Jatropha curcas. The total phenol, flavonoids, flavonols and proanthocyanidin contents of the extracts were evaluated to determine their effect on the antioxidant property of
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We assessed the polyphenolic contents and antioxidant potential of the aqueous, ethanol and methanol stem bark extracts of Jatropha curcas. The total phenol, flavonoids, flavonols and proanthocyanidin contents of the extracts were evaluated to determine their effect on the antioxidant property of this plant, using standard phytochemical methods. The antioxidant and free radical scavenging activity of ethanol, methanol and aqueous extracts of the plant were also assessed against 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), ferric reducing, nitric oxide (NO), superoxide anion, (O2) and hydrogen peroxide (H2O2) using spectroscopic methods and results were compared with that of butylated hydroxyl toluene (BHT) and ascorbic acid as standards. The concentrations of different classes of phenolic compounds were higher in methanol and ethanol extracts compared to aqueous extracts. There was correlation between total phenol, total flavonoids, total flavonol and total proanthocyanidins (r = 0.996, 0.978, 0.908, and 0.985) respectively. There was correlations between the amount of phenolic compounds and percentage inhibition of DPPH radicals scavenging activity of the extract (r = 0.98). Findings from the present study indicated that J. curcas is a potential source of natural antioxidants and may be a good candidate for pharmaceutical plant based products. Full article
(This article belongs to the Special Issue Antioxidants)

Review

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Open AccessReview Inflammation, Oxidative Stress, and Obesity
Int. J. Mol. Sci. 2011, 12(5), 3117-3132; doi:10.3390/ijms12053117
Received: 14 March 2011 / Revised: 5 April 2011 / Accepted: 10 May 2011 / Published: 13 May 2011
Cited by 211 | PDF Full-text (219 KB) | HTML Full-text | XML Full-text
Abstract
Obesity is a chronic disease of multifactorial origin and can be defined as an increase in the accumulation of body fat. Adipose tissue is not only a triglyceride storage organ, but studies have shown the role of white adipose tissue as a producer
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Obesity is a chronic disease of multifactorial origin and can be defined as an increase in the accumulation of body fat. Adipose tissue is not only a triglyceride storage organ, but studies have shown the role of white adipose tissue as a producer of certain bioactive substances called adipokines. Among adipokines, we find some inflammatory functions, such as Interleukin-6 (IL-6); other adipokines entail the functions of regulating food intake, therefore exerting a direct effect on weight control. This is the case of leptin, which acts on the limbic system by stimulating dopamine uptake, creating a feeling of fullness. However, these adipokines induce the production of reactive oxygen species (ROS), generating a process known as oxidative stress (OS). Because adipose tissue is the organ that secretes adipokines and these in turn generate ROS, adipose tissue is considered an independent factor for the generation of systemic OS. There are several mechanisms by which obesity produces OS. The first of these is the mitochondrial and peroxisomal oxidation of fatty acids, which can produce ROS in oxidation reactions, while another mechanism is over-consumption of oxygen, which generates free radicals in the mitochondrial respiratory chain that is found coupled with oxidative phosphorylation in mitochondria. Lipid-rich diets are also capable of generating ROS because they can alter oxygen metabolism. Upon the increase of adipose tissue, the activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), was found to be significantly diminished. Finally, high ROS production and the decrease in antioxidant capacity leads to various abnormalities, among which we find endothelial dysfunction, which is characterized by a reduction in the bioavailability of vasodilators, particularly nitric oxide (NO), and an increase in endothelium-derived contractile factors, favoring atherosclerotic disease. Full article
(This article belongs to the Special Issue Antioxidants)
Open AccessReview Antioxidant Properties of Aminoethylcysteine Ketimine Decarboxylated Dimer: A Review
Int. J. Mol. Sci. 2011, 12(5), 3072-3084; doi:10.3390/ijms12053072
Received: 1 March 2011 / Revised: 25 April 2011 / Accepted: 29 April 2011 / Published: 12 May 2011
Cited by 8 | PDF Full-text (222 KB) | HTML Full-text | XML Full-text
Abstract
Aminoethylcysteine ketimine decarboxylated dimer is a natural sulfur-containing compound detected in human plasma and urine, in mammalian brain and in many common edible vegetables. Over the past decade many studies have been undertaken to identify its metabolic role. Attention has been focused on
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Aminoethylcysteine ketimine decarboxylated dimer is a natural sulfur-containing compound detected in human plasma and urine, in mammalian brain and in many common edible vegetables. Over the past decade many studies have been undertaken to identify its metabolic role. Attention has been focused on its antioxidant properties and on its reactivity against oxygen and nitrogen reactive species. These properties have been studied in different model systems starting from plasma lipoproteins to specific cellular lines. All these studies report that aminoethylcysteine ketimine decarboxylated dimer is able to interact both with reactive oxygen and nitrogen species (hydrogen peroxide, superoxide anion, hydroxyl radical, peroxynitrite and its derivatives). Its antioxidant activity is similar to that of Vitamin E while higher than other hydrophilic antioxidants, such as trolox and N-acetylcysteine. Full article
(This article belongs to the Special Issue Antioxidants)

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