• The Korean Journal of Physiology and Pharmacology
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• v.7 no.1
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• pp.39-45
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• 2003

Reactive oxygen species (ROS) have been suggested to be contributory factors in complications of diabetes mellitus. In the present study, we investigated the generation of superoxide, the lipid peroxide level measured as thiobarbituric acid reactive substances, the vasorelaxation of isolated thoracic aorta and the iNOS expression in kidney of streptozotocin induced diabetic rats. Sprague Dawley rats were divided into four groups: control, ascorbate (400 mg/kg rat weight daily in drinking water), diabetic (single dose of 50 mg of STZ/kg i.p.) and diabetic simultaneously fed with ascorbate for 12 wk. Rats in groups were studied at tri-weekly intervals (0 to 12 wk). Diabetic rats were evaluated periodically with changes of plasma glucose levels and body weight. The ascorbate supplimentation attenuated the development of hyperglycemia and weight loss induced by STZ injection in rats. In the present experimental condition, the ascorbate supplimentation had no significant effect on plasma glucose levels and changes in body weight of normal rate. The superoxide generation, formation of thiobarbituric acid reactive substance and iNOS expression in kidney were significantly increased in STZ-treated rats that were decreased by ascorbate supplimentation. The ascorbate supplimentation had no effect on vasorelaxation of isolated thoracic aorta. These results indicate that ascorbate supplimentation may exert an inhibitory effect on STZ-induced oxidative tissue damage through protection of pancreatic islet cells by scavanging reactive oxygen species. The ascorbate supplimentation may possibly attenuate the renal complication of diabetes mellitus.

• Journal of Ginseng Research
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• v.15 no.2
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• pp.139-143
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• 1991

This study investigated the relations between the photosynthetic rate and the activities of antioxidatile enzymes, glutathione reductase, ascorbate free radical reductase, ascorbate peroxidase, glutathione peroxidase, and ascorbate oxidase, in the leaves of Panax ginseng. Under the normal cultivation condition, Panax in showed lower g1utathione reductase and ascorbate free radical reductase activities the Glycine max. But P ginseng showed higher 91utathione Peroxidase, ascorbate Peroxidase, and ascorbate oxidase activities than C. Panax. Therefore, P. ginseng showed weak activities of reductases for the reduction of the oxidized antioxidants. Under the light intensity of 25 KLux, the reductases showed a decrease of over 75% after 24 hours. But the peroyoxidases decreased about 40%. These results showed that the decrease of reductases acitivities was consistent with the decrease of photosynthetic rate. Therefore, we consider that the regulation of antioxidative enzymes or the application of exogenous antioxidants will be effective means for the protection of photodamage in p. ginseng.

• Korean Journal of Microbiology
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• v.26 no.1
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• pp.44-51
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• 1988

The intracellular free radicals produced at different stages of cell cycle of Saccharomyces cerevisiae ATCC 24858 were investigated by means of electron spin resonance(ESR) spectroscopy. The synchronized cells by repeated starvation and refeeding revealed different ESR spectral pattern compared to that of asynchronized cells. Each spectrum centered at g=2.005, which indicates free radicals. The relative spin concentration was maximat at the end of DNA increase. The variation of the relative spin concentration at each distinct stage of the cell cycle was evaluated in relation to ascorbate concentration, L-galactonolactone oxidase activity, and ascorbate oxidase activity. The highest activities of L-galactonolactone oxidase and ascorbate oxidase were detected just before and at the maximum of relative spin concentration, respectively. And ascorbate concentration fluctuated through each stage of cell cycle with the changes of relative spin concentration, L-galactonolactone oxidase activity, and ascorbate oxidase activity. Thus it is suggested that intracellular free radicals should be related to cell cycle, interacted with ascorbate, and may play an important role in the cell cycle of Saccharomyces cerevisiae.

• The Korean Journal of Physiology and Pharmacology
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• v.22 no.1
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• pp.35-42
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• 2018

Ascorbic acid is one of the most well-known nutritional supplement and antioxidant found in fruits and vegetables. Calcium ascorbate has been developed to mitigate the gastric irritation caused by the acidity of ascorbic acid. The aim of this study was to compare calcium ascorbate and ascorbic acid, focusing on their antioxidant activity and effects on gastric juice pH, total acid output, and pepsin secretion in an in vivo rat model, as well as pharmacokinetic parameters. Calcium ascorbate and ascorbic acid had similar antioxidant activity. However, the gastric fluid pH was increased by calcium ascorbate, whereas total acid output was increased by ascorbic acid. In the rat pylorus ligation-induced ulcer model, calcium ascorbate increased the gastric fluid pH without changing the total acid output. Administration of calcium ascorbate to rats given a single oral dose of 100 mg/kg as ascorbic acid resulted in higher plasma concentrations than that from ascorbic acid alone. The area under the curve (AUC) values of calcium ascorbate were 1.5-fold higher than those of ascorbic acid, and the $C_{max}$ value of calcium ascorbate (91.0 ng/ml) was higher than that of ascorbic acid (74.8 ng/ml). However, their $T_{max}$ values were similar. Thus, although calcium ascorbate showed equivalent antioxidant activity to ascorbic acid, it could attenuate the gastric high acidity caused by ascorbic acid, making it suitable for consideration of use to improve the side effects of ascorbic acid. Furthermore, calcium ascorbate could be an appropriate antioxidant substrate, with increased oral bioavailability, for patients with gastrointestinal disorders.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.6
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• pp.631-640
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• 1999

The present study investigated the stimulatory effects of iron (or ascorbate) on cyclosporine-induced kidney mitochondrial damage. Damaging effect of $50\;{\mu}M$ cyclosporine plus $20\;{\mu}M\;Fe^{2+}$ on mitochondrial lipids and proteins of rat kidney and hyaluronic acid was greater than the summation of oxidizing action of each compound alone, except sulfhydryl oxidation. Cyclosporine and $100\;{\mu}M$ ascorbate showed an enhanced damaging effect on lipids but not on proteins. The peroxidative action of cyclosporine on lipids was enhanced with increasing concentrations of $Fe^{2+}.$ Ferric ion $(20\;{\mu}M)$ also interacted with cyclosporine to stimulate lipid peroxidation. Damaging action of cyclosporine on mitochondrial lipids was enhanced by ascorbate $(100\;{\mu}M\;and\;1\;mM)$. Iron chelators, DTPA and EDTA, attenuated carbonyl formation induced by cyclosporine plus ascorbate. Cyclosporine $(100\;{\mu}M)$ and $50\;{\mu}M\;Fe^{2+}$ $(or\;100\;{\mu}M\;ascorbate)$ synergistically stimulated degradation of $2-{\alpha}$ deoxyribose. Cyclosporine $(1\;to\;100\;{\mu}M)$ reduced ferric ion in a dose dependent manner, which is much less than ascorbate action. Addition of $Fe^{2+}$ caused a change in absorbance spectrum of cyclosporine in $230{\sim}350$ nm of wavelengths. The results show that cyclosporine plus iron (or ascorbate) exerts an enhanced damaging effect on kidney mitochondria. Iron and ascorbate appear to promote the nephrotoxicity induced by cyclosporine.

• Food Science of Animal Resources
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• v.28 no.5
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• pp.567-573
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• 2008

This study investigated the effects of sodium chloride, potassium chloride, potassium lactate and calcium ascorbate on the physico-chemical and sensory characteristics of sodium-reduced pork patties. Pork patties were prepared in 4 ways: T1 (control, 1.0% NaCl), T2 (0.6% NaCl, 0.4% KCl), T3 (0.7% NaCl, 0.3% potassium lactate) and T4 (0.7% NaCl, 0.3% calcium ascorbate). The pH, cooking loss, total plate counts, TBARS (2-thiobarbituric acid reactive substances), surface color (L, a, b) and sensory characteristics were evaluated. The partial substitution of NaCl with KCl and calcium ascorbate decreased the cooking loss and TBARS values, and enhanced microbial stability. The partial substitution of NaCl with potassium lactate significantly decreased TBARS values and enhanced microbial stability, but significantly increased cooking loss compared to the control after 1 and 4 days of storage. However, the surface color and sensory characteristics were not affected by any of the treatments.

• The Korean Journal of Pharmacology
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• v.21 no.1
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• pp.62-77
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• 1985

In tile Iron-catalyzed Haber-Weiss reaction to produce OH., the requirement for $O^{-}_{2}{\cdot}$ is only to reduce $Fe^{+++}$. Possibly, the role of $O^{-}_{2}{\cdot}$ can be replaced by other reducing agents. Ascorbate is one of them in biological system. In the present study, the ability of ascorbate to produce $OH{\cdot}$ in the presence of $Fe^{++}$ and $H_2O_2$ was investigated by observing the degradation of hyaluronic acid and ethylene production from methional. Ascorbate stimulated the degradation of hyaluronic by $Fe^{++}$ and $H_2O_2$. That was confirmed by both viscosity change and gel-permeation chromatographic analysis. The observed degradation was almost completely prevented by catalase and $OH{\cdot}$ scavengers. In support of the above results, ascorbate enhanced the prouction of ethylene from methional in the presence of $Fe^{++}$ and $H_2O_2$. Other reducing agents (cysteine, glutathione, NADH and NADPH) showed similar activities to ascorbate in the degradation of hyaluronic acid and ethylene production. But no stimulatory effects were observed with their oxidized forms such as NAD and NADP. Thus, it appears that reduction of the metal ion was needed for $OH{\cdot}$ production. Among the metal ions tested, $Fe^{++}$ showed most potent catalytic action in the production of $OH{\cdot}$ The results obtained support that ascorbate can substitute $O^{-}_{2}{\cdot}$ in the metal-catalyzed reactions, particularly with $Fe^{++}$ by which $OH{\cdot}$ is produced with $H_2O_2$. The significance of the ascorbate-dependent production of $OH{\cdot}$ was considered with respect to possible role of ascorbate in the damage of inflamed joints.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.346-349
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• 2002

Effect of EDTA, gallic acid, phosphoric acid, propyl gallate and sodium ascorbate on the photostability of anthocyanin extracted from purple-fleshed sweet potato were investigated by measuring the absorbance at 530 nm with a spectrophotometer. White light of 20,000 lux was used to illuminate the pigment and the temperature was $20^{\circ}C$. EDTA and sodium ascorbate were more effective in improving the photostability of the pigment when added at least 100 or 1,000 ppm, respectively.

• Journal of Ginseng Research
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• v.18 no.3
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• pp.175-181
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• 1994

We studied the folilar wiping effects of antioxidants (ascorbate, glutathione and sodium azide), which effectively inhibited the chlorophyll bleaching or completely recorved the early stage of photosynthesis of Panax ginseng C.A. Meyer, on photosynthesis, stomatal resistance, free sugar, starch, and total saponin contents of ginseng under the excess light intensity (45 kLux) during 6 days. Ascorbate and glutathione, endogenous antioxidant, recovered photosynehtsis and stomatal resistance, and reduced the photoinhibition by the excess light intensity (45 kLux) on free sugar, starch and total saponin contents. But sodium azide, exogenous $^{1}O_2$ quencher, showed negative effect. Therefore, we assumed that carbohydrates and saponin metabolisms of ginseng by antioxidants (ascorbate, glutathione) were normal. For the reduction of inhibition by excess light in ginseng a program for the higher activation of antioxidants and antioxidative enzymes in ginseng leaf will be desirable. Key words Antioxidants, ascorbate, glutathione, Photoinhibition, ginseng.

• Journal of Pharmaceutical Investigation
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• v.21 no.4
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• pp.253-262
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• 1991

Microencapsulation of sodium ascorbate with cellulose acetate phthalate(CAP) by coacervation/ phase separation method were carried out. Various factors affecting microencapsulation, i.e., surfactant concentration. CAP concentration, stirring speed and treatment of spermaceti as a sealing agent were studied. Dissolution rate. particle size distribution, surface feature and stability test were investigated. CAP microcapsules prepared using 0.5% span 80 as a surfactant showed smooth and round surfaces. The release of sodium ascorbate was retarded by microencapsulation with CAP and by sealant treatment with spermaceti. When triturated with sodium bicarbonate, CAP microcapsules were more stable than unencapsulated sodium ascorbate under various RH conditions at $37^{\circ}C$.