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Lee Soo-Bok - - 2004
Glycosylated ascorbic acids were synthesized by using the transglycosylation activity of Bacillus stearothermophilus maltogenic amylase with maltotriose to show effective antioxidative activity with enhanced oxidative stability. The modified ascorbic acids comprised mono- and di-glycosyl transfer products with an alpha-(1,6)-glycosidic linkage. The antioxidative effects of the glycosyl derivatives of ascorbic acid ...
Abid N - - 2004
AIMS: To characterize hypochlorous acid (HOCl) stress resistance of Staphylococcus aureus and to assess physiological state and changes in cell morphology. METHODS AND RESULTS: Clinical wild-type strain of S. aureus was used in the stress with HOCl at concentrations ranging from 0 to 4 mg l(-1). Concentrations below 1.5 mg ...
Deaton Christopher M - - 2004
OBJECTIVE: To determine the pulmonary epithelial lining fluid (ELF) concentrations and degree of oxidation of ascorbic acid in horses affected by recurrent airway obstruction (RAO) in the presence and absence of neutrophilic airway inflammation. ANIMALS: 6 RAO-affected horses and 8 healthy control horses. PROCEDURE: Nonenzymatic antioxidant concentrations were determined in ...
Ely John T - - 2004
The approximately 4000 'normal' mammals that synthesize ascorbic acid produce on average circa 50 mg/kg per day routinely. Although humans have the same needs as normal mammals, they do not produce ascorbic acid at all and, on average, ingest only circa 1 mg/kg per day. The normal mammals' much larger ...
Mahan D C - - 2004
Ascorbic acid synthesis in the pig occurs at mid-pregnancy, but activity of the enzyme l-gulono-gamma-lactone oxidase (GLO) declines thereafter during gestation and remains low when the pig nurses the sow. During late gestation the ascorbic acid concentration in the fetus increases, but serum and liver ascorbic acid concentration in the ...
Satyanarayana S - - 2004
The antioxidant activity of the aqueous extracts of five umbelliferous fruits--caraway (Carum carvi), coriander (Coriandrum sativum), cumin (Cuminum cyminum), dill (Anethum graveolens) and fennel (Foeniculum vulgare)--were investigated in comparison with the known antioxidant ascorbic acid in in vitro studies. The amount of aqueous extract of these five umbelliferous fruits and ...
Erb Carl - - 2004
AIM: To study the antioxidant activity, UV absorption, concentration and stability of ascorbic acid (AA) in porcine and bovine aqueous humour (AH). METHODS: Porcine and bovine AH was taken within 5 min after death and frozen at -70 degrees C. The characteristic UV absorption band of AA and the concentration ...
De Sanctis Roberta - - 2004
Rhodiola rosea L. (Crassulaceae) is a plant living at high altitudes in Europe and Asia. Its roots have long been used in the traditional medical system of these geographical areas to increase the organism resistance to physical stress; today, it has become an important component of many dietary supplements. In ...
Pal R K - - 2004
Guava (Psidium guajava) fruits of cv. L-49 with individual shrink wrapping using 9 micro LLDPE film could be successfully stored up to 12 days at ambient and 18 days in evaporative cool chamber with negligible loss in vitamin C content. The untreated fruits lose 25-30% of ascorbic acid within 1 ...
Lavoie Jean-Claude - - 2004
BACKGROUND: When solutions of multivitamin preparations (MVPs) are exposed to light, H(2)O(2) as well as organic peroxides are generated and the concentration of vitamin C decreases. The aim of this study was to determine, using mass spectrometry, whether the generation of oxidative byproducts of vitamin C, such as dehydroascorbate (DHA) ...
Takaya Yoshiaki - - 2003
Methanol extracts of 11 kinds of commonly available vegetables were examined for hydroxyl radical scavenging potency using the bleomycin-Fe method. In this method, the iron ion and bleomycin in water form hydroxyl radicals, and the scavenging activity is monitored by the modified thiobarbituric acid method. All extracts showed scavenging capacity, ...
Alwazeer Duried - - 2003
The aim of this paper was to study the effect of both redox potential (Eh) and pasteurization of orange juice on stability of color and ascorbic acid, and growth recovery of microorganisms during storage at 15 degrees C for 7 weeks. Three conditions of Eh, +360 mV (ungassed), +240 mV ...
Agrawal Ganesh Kumar - - 2003
We have identified and characterized two rice ascorbate peroxidase (OsAPX1 and OsAPX2) genes against diverse signals known to involve in defense/stress responses, using "2-week-old rice seedling in vitro model system". Oryza sativa ascorbate peroxidase 1 and 2 (OsAPX1/2) share 83% similarity to each other at amino acid level and belong ...
Lykkesfeldt Jens - - 2003
Tobacco smoke contains large numbers of radicals that burden the antioxidant defense and, thus, lower plasma antioxidants, in particular vitamin C or ascorbic acid, is commonly observed among smokers. Ascorbic acid recycling describes the process in which ascorbic acid is oxidized to dehydroascorbic acid by various pathways and subsequently reduced ...
Datta Madhuban - - 2003
Static bioassays were made to evaluate efficiency of supplementation of ascorbic acid to remove stress of pyrethroid pesticide deltamethrin from freshwater catfish Clarias gariepinus. Clarias gariepinus exhibited several symptoms of stress when treated with deltamethrin (0.005 mg/l) for 24 h. Hepatosomatic index, liver glycogen, ascorbic acid of blood, liver, and ...
Wei D Z - - 2003
A mixture of (-)-epigallocatechin-3-gallate (EGCG) and ascorbic acid exhibited 73.2% inhibition of SMMC-7721 cell proliferation in a soft agar colony formation assay, which was much higher than EGCG (40.4%) or ascorbic acid (12.4%) alone. In the cell migration assay, the mixture also significantly suppressed the migration of SMMC-7721 cells by ...
Shukla Ram S - - 2003
The reduction of ferrofluid (FF) by L-ascorbic acid (H(2)A) and the reoxidation of the reduced FF to its original form by hydrogen peroxide have been investigated in aqueous acidic medium. The rate of reduction of FF was found to be first order with respect to [H(2)A] and [FF] and independent ...
Klein Ifat - - 2003
Peroxidase activity in human saliva is composed of salivary peroxidase (80%), of salivary glandular origin, and myeloperoxidase (20%), of leukocyte origin. The term oral peroxidase (OPO) is used here to denote the total activity of both peroxidase species. Using the 2-nitrobenzoic acid-thiocyanate assay, OPO activity was measured in the saliva ...
Hains Peter G - - 2003
UV light has often been investigated as a risk factor for the most common cause of blindness, human age-related cataract. One mechanism whereby UV light could induce cataract is via the action of photosensitisers. In this regard, xanthurenic acid has recently been highlighted since it has been reported to be ...
Balamurugan R - - 2003
BACKGROUND: Malondialdehyde (MDA), ascorbic acid and reduced glutathione (GSH) have been reported to play a possible role in glycation of proteins. This study was performed to evaluate this correlation in nephrotic syndrome patients by comparing the levels of fructosamine with MDA, ascorbic acid and GSH. METHODS: Fifteen children with nephrotic ...
Stamatelopoulos Kimon S - - 2003
Short-term cigarette smoking is associated with persistent endothelial dysfunction. Data on the reversibility of this effect with per os antioxidants after short-term smoking are lacking. This study examines the effect of orally administered ascorbic acid on cigarette smoking-induced endothelial dysfunction. In the present double-blind, randomized, crossover study, 19 healthy subjects ...
Sakihama Yasuko - - 2003
Peroxynitrite (ONOO(-)), a reactive nitrogen species, is capable of nitrating tyrosine residue of proteins. Here we show in vitro evidence that plant phenolic compounds can also be nitrated by an ONOO(-)-independent mechanism. In the presence of NaNO(2), H(2)O(2), and horseradish peroxidase (HRP), monophenolic p-coumaric acid (p-CA, 4-hydroxycinnamic acid) was nitrated ...
Dansby M Y - - 2003
Extruded ready-to-eat breakfast cereals (RTEBCs) were made from varying levels of sweetpotato flour (SPF), whole-wheat bran (WWB), and extrusion cooking. Moisture, protein, and ash contents were lower in the 100% SPF than the 100% WWB. Carbohydrate, beta-carotene, and ascorbic acid contents were higher in the 100% SPF. Fat, thiamin, riboflavin ...
Kimura Yukitaka - - 2003
The anti-oxidant activity of acyl ascorbates, with acyl chain lengths of 10 to 18, was measured in an intestinal epithelial cell line. All the acyl ascorbates exhibited the activity for the oxidization induced by three different types of oxidants, at levels higher than ascorbic acid. Myristoyl ascorbate was the most ...
Wee Liang Meng - - 2003
Ascorbate and several polyphenolic compounds have been reported to undergo oxidation in cell culture media to generate hydrogen peroxide (H2O2), but the mechanism underlying this has not been established. We therefore investigated the parameters affecting H2O2 production. H2O2 generation from ascorbate, gallic acid and other phenolic compounds in Dulbecco's Modified ...
Lee Jun-Beum - - 2003
The present study was carried out to examine the stability of microencapsulated ascorbic acid in simulated-gastric and intestinal situation in vitro and the effect of microencapsulated ascorbic acid on iron bioavailability. Coating materials used were polyglycerol monostearate (PGMS) and medium-chain triacylglycerol (MCT), and core materials were L-ascorbic acid and ferric ...
Takahama Umeo - - 2003
A salivary component, nitrate, is reduced to nitrite in the oral cavity. Polyphenols in foods are mixed with nitrite in the saliva to be swallowed into the stomach. An objective of the present study is to elucidate reactions between a polyphenol quercetin and a nitrite under acidic conditions. Nitric oxide, ...
Iijima Katsunori - - 2003
High luminal concentrations of nitric oxide are generated at the human gastro-oesophaegal junction and within Barrett's oesophagus due to the reduction of salivary nitrite to nitric oxide by acidic gastric juice. Salivary nitrite is derived from the entero-salivary recirculation of dietary nitrate. Our aim was to determine whether nitric oxide ...
George Joseph - - 2003
BACKGROUND: Ascorbic acid is a potent antioxidant and is involved in many metabolic activities including collagen biosynthesis. In the present investigation, ascorbic acid and lipid peroxides were monitored in the blood and liver samples during the progression of experimentally induced hepatic fibrosis. METHODS: Liver injury was induced by intraperitoneal injections ...
Takebayashi Jun - - 2003
The 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS (radical +)) decolorization assay was applied to evaluate the stoichiometric radical scavenging activity of ascorbic acid (AA) and two AA derivatives, 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G) and 2-O-alpha-D-glucopyranosyl-6-O-octanoyl-L-ascorbic acid (6-Octa-AA-2G). AA rapidly reacted with ABTS (radical +), and the reaction was completed within 10 min. In ...
Ebihara Mutsuhito - - 2003
BACKGROUND: Percutaneous absorption of ascorbic acid is limited by its impermeability and instability. OBJECTIVE: We attempted to improve the percutaneous absorption of ascorbic acid by use of iontophoresis after topical application of ascorbic acid. METHODS: Radioactivities extracted from epidermal, dermal and blood compartments after topical application of [14C]ascorbic acid was ...
Raoof Jahan-Bakhsh - - 2003
A carbon-paste electrode spiked with 1-[4-(ferrocenyl ethynyl)phenyl]-1-ethanone was constructed by the incorporation of 1-[4-(ferrocenyl ethynyl)phenyl]-1-ethanone in a graphite powder silicon oil matrix. It shown by cyclic voltammetry and double potential-step chronoamperometry, which this ferrocene derivative modified a carbon-paste electrode, can catalyze the ascorbic acid oxidation in an aqueous buffered solution. ...
Pokorski M - - 2003
The reducing properties of ascorbic acid in the carotid body make it a likely modifier of hypoxia-sensing mechanisms. This open-label study aimed to determine the effect of ascorbic acid on the hypoxic ventilatory response (HVR) in a population of elderly women, in whom both hypoxic reactivity and ascorbic acid levels ...
Müller-Moulé Patricia - - 2003
The ascorbate content of plants is usually increased in high light (HL), implying a function for ascorbate in the acclimation of plants to HL. Nevertheless, the importance of ascorbate in HL acclimation has not yet been tested directly. Here, we report on the acclimation process of an ascorbate-deficient Arabidopsis mutant ...
Naidu K Akhilender - - 2003
Ascorbic acid is one of the important water soluble vitamins. It is essential for collagen, carnitine and neurotransmitters biosynthesis. Most plants and animals synthesize ascorbic acid for their own requirement. However, apes and humans can not synthesize ascorbic acid due to lack of an enzyme gulonolactone oxidase. Hence, ascorbic acid ...
Ohsawa Koh-ichi - - 2003
The genotoxicity of endogenously formed N-nitrosamines from secondary amines and sodium nitrite (NaNO(2)) was evaluated in multiple organs of mice, using comet assay. Groups of four male mice were orally given dimethylamine, proline, and morpholine simultaneously with NaNO(2). The stomach, colon, liver, kidney, urinary bladder, lung, brain, and bone marrow ...
Suzuki H - - 2003
BACKGROUND: We have examined the suitability of microdialysis probes for examining nitrosative chemistry within localized regions of the lumen of the gastrointestinal tract. Chemical nitrosation occurs maximally at pH 2.5 in the presence of nitrite and thiocyanate and absence of ascorbic acid. Nitrite and thiocyanate are delivered into the stomach ...
Okorukwu Odilia N - - 2003
We have evaluated the inhibition of testicular hyaluronidase and hyaluronan lyase by L-ascorbic acid and chemical analogs. We observed that L-ascorbic acid, D-isoascorbic acid and dehydroascorbic acid inhibited both types of enzymes, but showed stronger effects towards hyaluronan lyase. But these compounds were observed to degrade the substrate, hyaluronan, by ...
Bornstein Stefan R - - 2003
Ascorbic acid (vitamin C) is a cofactor required in catecholamine synthesis for conversion of dopamine to norepinephrine by dopamine beta-hydroxylase. Mutant mice lacking the plasma membrane ascorbic acid transporter (SVCT2) have severely reduced tissue levels of ascorbic acid and die after birth. We therefore investigated whether these mice might have ...
Young J F - - 2003
In order to ameliorate a negative effect of stress on meat quality characteristics, chickens were fed a diet supplemented with a combination of ascorbic acid (1,000 ppm) and alpha-tocopherol (200 ppm) or oregano (3%), which has a high content of antioxidants. Chickens were slaughtered by cervical dislocation in the stable ...
Jansson Patric J - - 2003
We have previously shown that Vitamin C (ascorbic acid) can trigger hydroxyl radical formation in copper contaminated household drinking water. We report here that the capacity of ascorbic acid to catalyze hydroxyl radical generation in the drinking water samples is strongly dependent on the bicarbonate concentration (buffer capacity and pH) ...
Stabler Thomas V - - 2003
BACKGROUND: Ascorbic acid plays an important role in collagen synthesis. Though ascorbic acid concentrations in many tissues and in plasma have been characterized, little is known about in vivo levels in cartilage. MATERIALS AND METHODS: To discern the role of ascorbic acid in cartilage, we conducted a dose-response study measuring ...
Suzuki H - - 2003
Saliva has a high nitrite concentration, derived from the enterosalivary recirculation of dietary nitrate, and is the main source of nitrite entering the acidic stomach. Acidification of nitrite in the presence of secondary amines or amides generates potentially carcinogenic N-nitroso compounds. The reaction is inhibited by ascorbic acid and catalysed ...
Simon Joel A JA General Internal Medicine Section (111A1), Medical Service, San Francisco Veterans Affairs Medical Center, 4150 Clement Street, San Francisco, CA 94121, USA. - - 2003
To examine the relation between serum ascorbic acid and Helicobacter pylori serology from a probability sample of US adults. Data from 6,746 adults (ages 20 to 90 years) enrolled in the Third National Health and Nutrition Examination Survey (NHANES III), 1988-1994 were analyzed. Multiple logistic regression models were examined taking ...
Franck Christine - - 2003
L-ascorbic acid (L-AA) concentration changes during the development of cv. Conference pears and the influence of postharvest handlings (gas condition, cooling rate, cooling duration) on L-AA breakdown were studied. L-AA concentration fluctuates in young fruits, remains stable during fruit maturation, and starts to decline 1 week before commercial harvest. The ...
Strålsjö Lena - - 2003
Folate concentrations in rosehips and commercial rosehip products and factors affecting folate retention during drying were investigated. On the basis of the raw material studied during 3 years, rosehips were shown to be a rich folate source, 400-600 microg/100 g based on dry matter and 160-185 microg/100 g based on ...
Hasan M Y - - 2003
Lead is a common environmental toxin that affects neuromuscular junction and potentially might cause muscle weakness. Antioxidants like ascorbic acid may protect against lead induced myopathy. The present study measured isometric twitch tensions (evoked either directly by muscle stimulation or indirectly by nerve stimulation) to study effects of ascorbic acid ...
Takanaga Hitomi - - 2004
l-Ascorbic acid (vitamin C) is an effective antioxidant and an essential cofactor in numerous enzymatic reactions. Two Na(+)-dependent vitamin C transporters (SVCT1 and SVCT2) are members of the SLC23 human gene family, which also contains two orphan members. SVCT1 and SVCT2 display similar properties, including high affinity for l-ascorbic acid, ...
Bradshaw Mark P - - 2003
An examination of the ascorbic acid-induced oxidation of (+)-catechin was carried out. Using varying concentrations of ascorbic acid in a model white winebase, it was observed that there are at least two distinct steps in its oxidation process. The first step involves the formation of species that absorb in the ...
Ringvold Amund - - 2003
OBJECTIVE: To evaluate the absorbance of ultraviolet radiation (UVR) in the aqueous humor of various animal species in relation to the ambient radiation of their respective habitats, and to identify substances responsible for this absorbance. Representatives of all five classes (fish, amphibian, reptile, bird, and mammal) have been tested. METHODS: ...
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