• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.2
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• pp.101-106
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• 2002

This study was conducted to obtain the transformed tobacco (Nicotiana tubacum) plants with cytosolic ascorbate peroxidase gene(ApxSC7) using Agrobacterium tumefaciens LBA4404. A cDNA encoding the cytosolic ascorbate peroxidase of strawberry, ApxSC7, was introduced into tobacco plants via Agrobacterium-mediated gene transfer system. The expression vector, pIG-AP8, harboring ApxSC7 gene was used for production of transgenic tobacco plants. A large number of transgenic plants were regenerated on a medium containing hygromycin. Integration of ApxSC7 gene was confirmed by PCR and Southern blot analyses with genomic DNA. Northern blot analyses revealed that the pIGap8 gene was constitutively expressed.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.881-888
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• 2000

Lactic acid bacteria(LAB) fermented food was prepared with milk or egg white powder(EWP) and added with freeze drying protectant(FDP). 0.2% of Tween 80 or 1% of ascorbate was added to milk sample and 3% of raffinose or 1% of ascorbate was added to EWP sample. Effects of FDP on sensory property, volatile aroma compounds and physical property of LAB fermented food were investigated. In case of non-freeze dried samples, sensory properties of milk sample with ascorbate were slightly better than those of reference sample(milk), while sensory properties of EWP sample or EWP sample with FDP were slightly inferior to reference sample. Sensory properties of all of the freeze dried/reconstituted samples were not different. Sensory properties of milk sample with ascorbate were reduced by freeze drying/reconstitution, while those of sample with ascorbate were not changed. Although all of the volatile aroma compounds were reduced by freeze drying, the residual ratio was slightly different between milk samples and EWP samples. Difference in volatile aroma compounds between milk samples and EWP samples before freeze drying was relatively large, while difference between two sample groups after freeze drying/reconstitution was relatively small. Rheological properties of milk samples were markedly changed by freeze drying/reconstitution, while those of EWP samples were changed slightly.

• Korean Journal of Plant Tissue Culture
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• v.25 no.5
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• pp.289-293
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• 1998

We investigated the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity in methanol extracts of 64 cultured cell lines, which were derived from various plant species, and the ascorbate content in cell lines, which showed a high radical scavenging activity. Thirteen cell lines revealed the antioxidative activity ($IC_{50}$) by methanol extracts of less than 50 mg in cell fresh wt. Of them, six cell lines showed the same Rf value as ascorbate on the DPPH sprayed silica gel TLC. The ascorbate content in cell lines of Rosa multiflora, Scutellaria baicalensis, and Achyranthes japonica showed 48.5, 30.3, and $16.8\;\mu\textrm{g}$ per g cell fresh wt by HPLC analysis, respectively. In callus cultures of S. baicalensis, the concentration of ascorbate reached a maximun ($39{\pm}3.4\;\mu\textrm{g}/g$ cell fresh wt) on 30 days after subculture, which corresponded to the stationary growth phase, and subsequently decreased by successive culturing.

• Horticultural Science & Technology
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• v.29 no.1
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• pp.61-67
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• 2011

Barley (Hordeum vulgare L.) sprouts are a vegetable commonly used as a functional food material due to its high vitamin C concentration and antioxidant activity. In this experiment, we measured the changes in the antioxidant activity of several barley cultivars as well as in the concentrations of related compounds such as ascorbate and glutathione upon treatment with UV-B or salicylic acid (SA). The six barely cultivars were grown in a plant growth chamber (25/$18^{\circ}C$, 14/10 h, 200 ${\mu}mol{\cdot}m^{-1}{\cdot}s^{-1}$, 70% relative humidity) for 10 days. All barely cultivars showed different 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) scavenging activities, which were increased by UV-B treatment and not by SA treatment. The changes in ascorbate concentrations were correlated with DPPH scavenging activity in both the treatments, suggesting that the antioxidant activity in barley sprouts was mainly dependent on ascorbate concentration. Furthermore, changes in ascorbate concentration showed similar tendencies to changes in free sugar concentration, especially glucose and sucrose, in both treatments. On the other hand, the concentrations of glutathione and cysteine highly increased by SA treatment, representing different tendencies compared to the DPPH scavenging activity and ascorbate concentration. 'Donghanchal' cultivar showed comparatively higher antioxidant activity, both constitutively and inducingly by UV-B treatment, with its higher concentrations of ascorbate and glutathione. These results suggest that barley sprouts could be used as a health-functional vegetable, contributing to the overall supply of antioxidant and sulfur-containing organic compounds.

• Journal of Ginseng Research
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• v.24 no.3
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• pp.113-117
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• 2000

To analyze the correlation between the rusty root and the antiokidative activity in ginseng (Panax ginseng C.A.Meyer) roots, the levels of antioxidative activity in various tissues of healthy and rusty roots. The superoxide dismutase activity in rusty roots (126.9 units/mg protein) was approximately 3.5 times higher than that in healthy roots. The catalase activity in rusty roots was approximately 1.6 times higher than that in healthy roots, whereas the peroxidase activity showed a slight low level in msty roots. The 1.1 diphenyl-2-picryl-hydrazyl(DPPH) free radical scavenging activity in rusty roots was approximately 2.0 times higher than that in healthy roots. The total ascorbate content in healthy roots was 166~240 $\mu\textrm{g}$/g fr. wt. depending on the tissues. Interestingly, the oxidized dehydroascorbate (DHA) content occupied more than 80% in total ascorbate content. The total ascorbate content in rusty roots was a similar level with healthy roots, but the reduced ascorbate content was 3.5~7.5 times higher than that of the healthy roots. The total glutathione content of the epidermis, cortex and stele tissues in 겨sty roots was 7.3, 4.8, 1.2 times higher than the healthy tissues, respectively. The ratio of reduced glutathione (GSH) and oxidized glutathione (GSSG) showed a similar fluctuation of total glutathione content in 겨sty roots. These results indicate that the high antioxidative activity in rusty roots may involve in overcoming the oxidative stress derived from environmental stresses.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.2
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• pp.167-172
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• 2004

In the human skin, vitamin C (L -ascorbic acid) that is well known as the activated materials has effects that is skin anti-aging and wrinkle repair by giving impetus to collagen biosynthesis and anti-oxidation, and that is the sun screen, a wound recovering, inhibition melanogenesis and so on. In spite of its effects, vitamin C has the defects of the skin stimulation and easily oxidized instability by water, air, heat and light. For solving their matters, many investigation is advanced and its results are synthesized the various vitamin C derivatives. And yet they have not solved the unstable property of vitamin C and were still insufficient for the comparing with the effect of the pure vitamin C itself. In this study, in order to prepare vitamin C derivative of being improved the stability and to apply vitamin C effect in the skin, we prepared new vitamin C derivative, phytosphingosine ascorbate, by using phytosphingosine, one of sphingolipids, which have a distinguished skin affinity. Phytosphingosine ascorbate can be prepared as the ionic bond between amine group (-NH$_2$) of phytosphingosine and hydroxy group (-OH) of vitamin C by way of the relatively simple reaction. So the structure and properties of the synthesized phytosphingosine ascorbate was confirmed the use of elemental analysis (C 58.3 : H 9.3 : N 2.8 : O 29.5), MALDI TOF-MS (Mw=492.58), Ultraviolet spectra (268.5nm), lH NMR, FT-IR spectra, thermal analysis (m.p=l54$^{\circ}C$), HPLC and so on. And we could confirm the anti-bacterial and anti-oxidation effects. Based on these results, we could confirm to prepare a new material that was expected of both effects of vitamin C and phytosphingosine and that is improved properties of vitamin C.

• Journal of Food Hygiene and Safety
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• v.12 no.4
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• pp.304-309
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• 1997

A study was undertaken to determine the thermal inactivation of Escherichia coli O157:H7 as influenced by the effects of temperature, time, suspension medium and ascorbate. Tryptic soy broth was more heat resistant than pfosphate buffer (pH 7.1), with D values of 1.52~1.68 min at 6$0^{\circ}C$ and 1.51~1.63 min at 7$0^{\circ}C$ compared with 1.52~1.65 min at 6$0^{\circ}C$ and 1.26~1.61 min at 7$0^{\circ}C$ for phosphate buffer as suspension medium. E. coli O157:H7 was completely inhibited within 30 min when small inoculum (106 CFU/$m\ell$) was heated at 7$0^{\circ}C$. When E. coli O157:H7 was preheated at 48$^{\circ}C$ for 60 min in phosphate buffer before heating, D values were 1.28~1.60 min at 6$0^{\circ}C$, and 1.13~1.56 min at 7$0^{\circ}C$, showing that preheating increases the heat resistance of the strain. Phosphate buffer containing ascorbate (0.001 M) was enhanced the thermal inactivation of the strain when inoculated as large inoculum (109 CFU/$m\ell$), while ascorbic acid was no effect at low cell concentrations (109 CFU/$m\ell$).

• Journal of Pharmaceutical Investigation
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• v.24 no.3
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• pp.11-18
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• 1994

We have studied the iron uptake by the purified brush-border membrane vesicles (BBMVs) to determine the effect of fructose on the absorption of iron. BBMVs were prepared by the modified calcium precipitation method, The degree of purification was routinely assessed by the marker enzyme, alkaline phosphatase, and the functional integrity was tested by $D-[1-^3H]glucose$ uptake. The appearance of membrane vesicles was shown by transmission electron microscopy (TEM). The uptakes of complexes of labeled iron $[^{59}Fe]$ with fructose and ascorbate were measured with a rapid filtration technique, The uptake rate and pattern of the two iron-complexes, Fe(III)-fructose and Fe(III)-ascorbate, were also observed. A typical overshooting uptake of D-glucose was observed with peak value of $2{\sim}3$ times higher concentration than that at equilibrium. This result was similar to other studies with BBMVs. TEM showed that the size of BBMVs was uniform and we can hardly find any contaminants, Fe(III)-fructose has the higher value of $V_{max}$ and the lower value of Km than those of Fe(III)-ascorbate, respectively. It may be concluded that D-fructose is more effective in promoting the iron absorption than ascorbate.

• Preventive Nutrition and Food Science
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• v.5 no.4
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• pp.205-212
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• 2000

The relation of food and supplemental intake of iron, vitamin E and ascorbic acid and other lifestyle variables to packed cell volume (PCV) and serum vitamin levels was studied in urban and rural (71% Amish) communities. Subjects were interviewed (24-h dietary recalls) on three occasions over 18-months, and blood samples were taken (maximum observations = 442). Mean PCV was lower in rural males (43.3) than in urban males (45.4) despite higher man food iron intake (18.7 and 14.4 mg/day, respectively). Mean meal iron availability was higher at lunch and lower at breakfast and dinner for rural than for urban subjects. Smoking was the number one variable in males and females explaining variance in PCV. Supplemental vitamin E and ascorbate intakes explained the most variance in serum vitamin E and ascorbate levels, respectively. Serum vitamin E was also associated with supplemental ascorbate intake (r=0.29). Serum ascorbate was also associated with food ascorbate intake (r=0.28) and body weight (r=-0.24).

• Journal of Plant Biology
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• v.38 no.1
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• pp.47-54
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• 1995

The present study performed the isolation of cytosolic ascorbate peroxidase (APX) isozymes and analyzed the pattern of their activity development and also investigated the change in some other enzyme activities related to the ascorbate-glutathione pathway from the senescing wheat leaves. The aim of this work is to examine the possibility that in the cytoplasm of wheat leaves the ascorbate-glutathione pathway p!ays a significant role in relation to leaf senescence involving an $H_2O_2$ accumulation and then to show the effect of benzyladenine (BA) on that pathway. During the leaf senescence characterized by increases in ChI breakdown and H202 accumulation under the 4-day dark incubation of matured leaf segments; i) no significant increase of total cytosolic APX was observed, ii) a dehydroascorbate reductase (DHAR) activity was decreased rapidly, iii) a slight increase of glutathione reductase (GR) activity occurred. In the BA-treated leaves; however, i) the total activity of APX increased conspicuously, ii) the decrease of DHAR activity was relatively inhibited, iii) the GR activity increase was more enhanced, and iv) the decrease of ascorbate content and the increase of H202 content were retarded as compared with those of control leaves. Three isozymes of cytosolic APX were found by using a native-electrophoretic gel in senescing wheat leaves and two of them occurred with major activity. In the developmental patterns of cytosolic APX isozymes, only two isozyme bands ("a" and "b") appeared with almost constant activity through 4 days of incubation in the control leaves, while one additional weak isozyme band ("c") and a little increase of "b" isozyme activity were detected in the BA-treated leaves. EspeciaUy, the development of "a" isozyme activity increased remarkably compared with that of control leaves. The increased capacity for peroxide scavenging due to the enhanced activity of all 3 enzymes (APX, DHAR, GR) participating in the ascorbate-glutathione pathway in BA-treated leaves suggested that this pathway might playa significant role in the processes related to the wheat leaf senescence.scence.