• Applied Biological Chemistry
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• v.18 no.1
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• pp.52-55
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• 1975

A microdetermination of Ascorbic acid (AsA) in blood by Gas-Liquid Chromatography (GLC) was studied. AsA was applied on GLC after the conversion into trimethylsilyl derivative (TMS) and the GLC was available for the only reduced form of AsA. A calibration curve is made by GLC of TMS-AsA as the internal standard of n-docosane. The minimum amount of AsA required for the determination was 0.5ml of 1 mg% pyridine solution. Prior to the conversion of AsA in serum into TMS derivative, serum was lyophilized and then it was allowed to stand at room temperature with TMS reagents for 48 hr. On injection of the supernates of TMS derivative to GLC the peak corresponding to AsA was not detected. Its reason why the concentration of AsA in serum is $0.5mg{\sim}0.8mg%$ in general, and it is less than minimum concentration of GLC. In case of L-AsA 1 mg was added to 1ml of serum, which was followed by lyophilization, silylation and GLC. The recorvery of AsA added was 98 percentage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.5
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• pp.797-802
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• 2004

L-Ascorbic acid (AsA), commonly known as vitamin C, which is one of the antioxidant vitamins, plays a role in cellular oxidant quenching. Some of the biochemical reactions in which it takes part have been traced through organ culture technique. But in cell cultured system, views on stimulatory and inhibitory action of AsA on cell growth are conflicting. Therefore, this study aimed to clarify the inhibitory action of high concentration AsA on the cell growth in Primary chondrocyte isolated from rat ribs. Cells were exposed to ascorbate at various concentrations. Supplement of AsA induced stimulation of cell growth in primary cultured cells of chondrocytes. Most remarkable stimulation of cell growth by AsA was found in primary cultured chondrocytes. However, it showed that they were dead in the medium which contained AsA at the concentration higher than 1.0 mM. This lethal effect of AsA causing the cell death was inhibited by the addition of catalase in the medium. This supposed that hydroxyl radical (ㆍOH) induced from $H_2O$$_2$ was actively cytotoxic agent. Based on the results, when AsA was added in medium at normal concentrations, the cell growth was stimulated by inducing the formation of extracellular matrix. On the contrary, if added in medium at excess concentrations, the cell growth was inhibited because $H_2O$$_2$ were generated from AsA in medium. Therefore, addition of AsA at the normal concentrations stimulates cell growth, but excess concentrations of AsA induces cell death.

• Korean Journal of Microbiology
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• v.26 no.1
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• pp.52-59
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• 1988

A partially purified preparation of L-galactonolactone oxidase which catalyzes the last step of L-ascorbic acid biosynthesis was obtained from Saccharomyces cerevisiae ATCc 26787. The purification procedures included Triton X-100 treatment, protamine sulfate precipitation, ammonium sulfate precipitation, DEAE-Sepharose CL-6B ion exchange chromatography, Sephadex G-150 gel filtration chromatography, and Phenyl-Sepharose CL-4B hydrophobic interaction chromatography. The optimum temperature for the enzyme activity was about $34^{\circ}C$ and the optimum pH was 6.8-7.0. The substrate specificity was confined to L-aldonolactones, L-galactono-1,4-lactone and L-gulono-1,4-lactone. An apparent Km value of 0.294mM with L-galactono-1,4-lactone as a substrate was found. By comparing the substrate specificities of this enzyme with those of isofunctional enzymes of higher plants and animals, it becomes evident that the enzyme of S. cerevisiae ATCC 26787 is rather similar to the L-gulonolactone oxidase of animals than the galactonolactone dehydrogenase of higher plants.

• Journal of Plant Biotechnology
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• v.7 no.3
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• pp.155-160
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• 2005

Haloxylon recurvum (Locally known as Khar) is drought and salt tolerant plant of Thar Desert. This plant is a major biomass producer and has economic and ecological importance for the region. There is need for study on biology, propagation and genetic improvement for utilization of this plant for reclamation of saline soils. We report here on in vitro propagation of Haloxylon recurvum (Moq.) using nodal explant. Secretion of phenolic compound from explants was a major constraint for establishment of culture. This was checked by thorough washing and quick transfer of explant on fresh culture medium. Juvenile nodal explant with leaves was found suitable for culture establishment. Benzy-ladenine($4.0\;{\mu}M$) incorporated in Murashige and Skoog (MS) medium with additives (50 mg/L ascorbic acid and 25 mg/L each of adenine sulphate, arginine and citric acid) induced multiple shoots from nodal explant. Addition of $1.0\;{\mu}M$ naphthalene acetic acid (NAA) in combination with $4.0\;{\mu}M$ BAP improved the growth of axillary shoots. Further shoot amplification was achieved by repeated subculture of mother explants on fresh medium. Forty percent of the micropropagated shoots rooted on half-strength MS medium with $4.0\;{\mu}M$ indolebutyric acid (IBA) and 100 mg/L activated charcoal, at $28{\pm}2^{\circ}C$ and $60\%$ RH. Sixty percent of these plantlets were hardened in green house.

• Journal of Environmental Science International
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• v.18 no.3
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• pp.299-308
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• 2009

We manufactured PVA-derived hydrogels using a foam generation technique that has been widely used to prepare colloidal gas aphrons(CGA). These gels were differentiated to the conventional gels such as for medical or pharmaceutical applications, which have tiny pores and some crystalline structure. Rather these should be used in de-pollution devices or adhesion of cells or biomolecules. The crosslinkers used in this work were amino acid, organic acid, sugars and lipids(vitamins). The structures of the gels were observed in a scanned electron microscope. Amino acids gels showed remarkably higher swelling ratios probably because their typical functional groups help constructing a highly crosslinked network along with hydrogen bonds. Boric acid and starch would catalyze dehydration while structuring to result in much lower water content and accordingly high gel content, leading to less elastic, hard gels. Bulky materials such as ascorbic acid or starch produced, in general, large pores in the matrices and also nicotinamide, having large hydrophobic patches was likely to enlarge pore size of its gels as well since the hydrophobicity would expel water molecules, thus leading to reduced swelling. Hydrophilicity(or hydrophobicity), functional groups which are involved in the reaction or physical linkage, and bulkiness of crosslinkers were found to be more critical to gel's cross linking structure and its density than molecular weights that seemed to be closely related to pore sizes. Microscopic observation revealed that pores were more or less homogeneous and their average sizes were $20{\mu}m$ for methionine, $10-15{\mu}m$ for citric acid, $50-70{\mu}m$ for L-ascorbic acid, $30-40{\mu}m$ for nicotinamide, and $70-80{\mu}m$ for starch. Also a sensory test showed that amino acid and glucose gels were more elastic meanwhile acid and nicotinamide gels turned out to be brittle or non-elastic at their high concentrations. The elasticity of a gel was reasonably correlated with its water content or swelling ratio. In addition, the PVA gel including 20% ascorbic acid showed fair ability of cell adherence as 0.257mg/g-hydrogel and completely degraded phenanthrene(10 mM) in 240 h.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.2
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• pp.161-167
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• 2013

The aim of this study was to investigate the protective effects of methanolic extract from perilla (Perilla frutescens Britt var. japonica) leaves (PLME) on oxidative injury from hydrogen peroxide ($H_2O_2$) in human HaCaT keratinoctyes. Cells were co-incubated with various concentrations (0~200 ${\mu}g/mL$) of PLME for 24 hr, and then exposed to $H_2O_2$ (500 ${\mu}M$) for 4 hr. $H_2O_2$ significantly decreased cell viability (p<0.05). However, PLME provided protection from $H_2O_2$-induced HaCaT cell oxidation in a dose-dependent manner. To further investigate the protective effects of PLME on $H_2O_2$-induced oxidative stress in HaCaT cells, the cellular levels of lipid peroxidation, and antioxidant enzymes (including superoxide dismutase (SOD), glutathione peroxidase (GSH-px) and catalase (CAT)) were measured. PLME decreased cellular levels of lipid peroxidation, and also increased the activities of antioxidant enzymes. In addition, the antioxidant activities of PLME were also determined by DPPH and hydroxyl (${\cdot}OH$) radical scavenging assay, and major antioxidant compounds of PLME were measured by colorimetric methods. DPPH and ${\cdot}OH$ radical scavenging activities of PLME increased in a dose dependent manner and was similar to the DPPH scavenging activity of ascorbic acid at 50 ${\mu}g/mL$; however PLME activities were stronger than ascorbic acid (50 ${\mu}g/mL$) in the ${\cdot}OH$ scavenging assay. The amounts of antioxidant compounds, including total polyphenolics, total flavonoids, and total ascorbic acid from PLME were $52.2{\pm}1.1$ mg gallic acid (GAE)/g, $33.7{\pm}4.7$ mg rutin (RUE)/g, and $17.0{\pm}0.5$ mg ascorbic acid (AA)/g, respectively. These results suggest that PLME has a strong free radical-scavenging activity and a protective effect against $H_2O_2$-induced oxidative stress in the keratinocytes.

• Horticultural Science & Technology
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• v.34 no.4
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• pp.596-606
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• 2016

The growth and contents of anthocyanins and ascorbic acid in lettuce(Lactuca sativa L., 'Jeokchima') as affected by supplemental UV-A LED irradiation under different light quality and photoperiod conditions were analyzed in this study. Five light qualities, namely B (blue LED), R (red LED), BUV (blue LED+UV-A LED), RUV (red LED+UV-A LED) and Control (white fluorescent lamps) with photoperiods of 12/12 hours (day/night), 16/8 hours, or 20/4 hours were provided to investigate the effects of light quality and photoperiod on the growth and accumulation of anthocyanins and ascorbic acid in lettuce leaves. As measured 28 days after transplanting, the number of leaves, leaf length, leaf width, leaf area, shoot fresh weight and dry weight of lettuce were significantly affected by light quality and photoperiod. The number of leaves, leaf length, leaf width, leaf area, shoot fresh weight and dry weight of lettuce grown under R treatment increased with increasing light period. By contrast, leaf development was inhibited, but chlorophyll content increased, under B treatment. Supplemental UV-A irradiation significantly decreased leaf length, leaf width, leaf area and shoot fresh weight. Anthocyanins in lettuce increased significantly with decreasing dark period under B treatment. A synergistic effect of supplemental UV-A LED irradiation on anthocyanins accumulation was found for lettuce leaves grown under R treatment but not B treatment. Ascorbic acid in lettuce was greatly affected by photoperiod. Ascorbic acid content at BUV and RUV treatments increased by 20-30% compared to without UV-A LED irradiation. From these results, it was concluded that growth and contents of anthocyanins and ascorbic acid in lettuce are significantly affected by supplemental UV-A LED irradiation. The results obtained in this study will be informative for efforts to improve the nutritional value of leafy vegetables grown in plant factories.

• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.293-302
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• 1988

This study was performed to identify detailed informations on the nonvolatile flavor of Chinese quince fruits, Chaenomeles sinensis koehne. About 72% of the free amino acids were shown to be valine, asparagine, ${\gamma}-aminobutyric\;acid$, aspartic acid and serine. Arginine, tyrosine, methionine and tryptophan were not present. Glutamic acid and glutamine as a amino acid for peptides were the major components, whereas cysteic acid, methionine sulfone and tryptophan were not detected. The nucleotides attained were composed of cytosine, uridine-5'-monophosphate and cytidine-5'-monophosphate, and these were proved to be a very small quantity. Guanosine-5'-monophosphate, inosine-5'-monophosphate and adenosine-5'-monophosphate were not present. The major sugars were shown to be glucose, sorbose, sucrose and fructose. Fructose was the most abundant one among them. A total of 11 organic acids were identified by capillary gas chromatography and capillary gas chromatography-mass spectrometry. The major components identified were tartaric acid and α-ketoglutaric acid. The total content of vitamin C determined was 386.6mg%, and those of ascorbic, dehydroascorbic, and 2, 3-diketo-L-gulonic acid were 28.8mg%, 154.5mg% and 197.3mg%, respectively. Calcium and phosphorus were the major components, while heavy metals such as cadmium, copper and lead were determined to be a small amount. In the result of organoleptic test on the natural and synthetic extract of Chinese quince fruits, the principal taste components consisted of free amino acids, sugars, organic acids, vitamin C and minerals. Five groups mentioned would have a favorable influence upon the taste of fresh Chinese quince fruits.

• Journal of the Korean Society of Food Culture
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• v.20 no.5
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• pp.603-607
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• 2005

Fourteen phenolic compounds(benzoic acid, p-hydroxybenzoic acid, protocatechuic acid, vanillic acid, syringic acid, gallic acid, caffeic acid, ferulic acid, (+)-catechin, quercetin, rutin, catechol, chlorogenic acid and L-ascorbic acid) were examined for their effects on the anticarigenic activity. Among tested samples, catechol was significantly inhibited the S. mutans, exhibiting an clear zone 18.5-19.5mm by 10 mg/disc level. The minimal inhibition concentration(MIC) of the phenolic compounds for Streptococcus mutans, M1 and M2 strain were determined as 2,000 ppm, whereas catechol was 1,000 ppm. The activity of glucosyltransferase(GTase) was significantly inhibited by catechol, at 10 ppm(58.7%), 50 ppm(60.7%) and 100 ppm(88.4%) and 500 ppm(89.6%), respectively. Among them, catechol showed most significant anticariogenic activity as well as inhibition of GTase activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.11
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• pp.1685-1690
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• 2016

Xanthine oxidase (XO) inhibitors play an important role in the treatment of gout and many other diseases related to superoxide anion metabolism. In this study, four commercial fruit juices and three vinegars were evaluated for their inhibitory activity of XO (XOI), as well as contents of organic acids by HPLC with UV detection. Five different organic acids were detected in commercial samples: acetic acid and malic acid were the most prominent in vinegars and fruit juices, respectively. The vinegars showed high XOI activity (33.8~64.9%) related to the great concentration of acetic acid ($R^2=0.7192$). The presence of acetic acid in vinegar could be responsible for its XOI effect.