• KSBB Journal
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• v.23 no.1
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• pp.96-100
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• 2008

In this work, we describes analysis of the antioxidant potential of Korean green tea phenolics using an high-performance liquid chromatography (HPLC) on-line $ABTS^{+}$ antioxidant screening method. In conjunction with the analysis of their 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS+) radical scavenging ability, the extraction of catechine compounds from Korean green tea were performed by various temperature and time. The optimum operating conditions were experimentally determined to analyze the catechine compounds in the pretreatment extracts. From the results, the extraction temperature $60^{\circ}C$, time 3 min was selected as an optimal antioxidant activity condition. The analysis by $C_{18}$ column was performed, the flow rate of mobile phase and UV wavelength was fixed at 1.0 ml/min and 254 nm, respectively. the mobile phase was composed from acetonitrile and water, and the gradient elution mode were applied.

• Natural Product Sciences
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• v.22 no.2
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• pp.87-92
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• 2016

Endothelial dysfunction in atherosclerosis is associated with increasing oxidative stress that could be reversed by antioxidant. Therefore epigallocatechin gallate (EGCG), epicatechin gallate (ECG), epigallocatechin (EGC) and catechin (C) of tea flavonoids were investigated for their roles in regenerating endothelial cell. Peripheral blood mononuclear cells (PB-MNCs) were isolated, plated and cultured in medium with/without treatment of EGCG, ECG, EGC and C. Results showed that among all EGCG, ECG, EGC and C concentrations tested, $12.5{\mu}mol/L$ was not cytotoxic for peripheral blood-derived endothelial progenitor cells (PB-EPCs). Treatment of EGCG, ECG, EGC or C increased the percentages of CD34, CD133, VEGFR-2 expressions and suppressed hydrogen peroxide-induced percentages of reactive oxygen species (ROS) level in PB-EPCs. Taken together, our current results showed that EGCG, ECG, EGC or C of tea flavonoids could induce differentiation of PB-MNCs into PB-EPCs as well as protect PB-EPCs from oxidative damage by suppresing the intracellular ROS levels.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.11
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• pp.1501-1506
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• 2011

In this study, we optimized the reaction conditions for the bioconversion of green tea using tannase, and to evaluate its radical scavenging activities. Tea catechins such as (-)-epigallocatechin gallate (EGCG) or (-)-epicatechin gallate (ECG) were hydrolyzed by tannase to produce (-)-epigallocatechin (EGC) or (-)-epicatechin (EC), respectively, and a common product, gallic acid. The bioconversion of tea catechins by tannase was increased as enzyme concentration, substrate concentration and incubation time for enzyme dose. The results indicated the optimum reaction conditions for tannase were tannase 30 U/mL (enzyme concentration) on 1% green tea (substrate concentration) for 1 hr (incubation time for enzyme). Tannase enhanced the radical-scavenging properties of green tea; the 2,2-azinobis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals scavenging abilities were significantly (p<0.001) greater for the tannase-treated green tea extract compared to the untreated green tea extract. It is reported that ECG has the greatest antioxidant activity among the catechins in green tea, and the release of gallic acid is considered to be beneficial because of its significant antioxidant potency. The results of this study suggest that the tannase-treated green tea increases antioxidant activities under optimum reaction conditions.

• Natural Product Sciences
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• v.23 no.2
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• pp.146-150
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• 2017

Alnus sibirica (AS) geographically distributes in Korea, Japan, Northeast China and Russia. The bark of this plant had been used for antipyretic, expectorant, anti-phlogistic, antitussive, anti-asthmatic and as a health tea for alcoholism. Recently, we studied various biological activities of AS and the isolated diarylheptanoid. In present study, we conducted fermentation of AS (FAS) and isolated two diarylheptanoid (hirsutenone and muricarpone B). Moreover, we established the validation and contents determinations of the two compounds by HPLC on FAS.

• Journal of the Korean Society of Food Science and Nutrition
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• v.16 no.2
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• pp.105-109
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• 1987

The mineral content of Dolowe, which were prepared in the laboratory and marketed Korean products of Dolwoe, Japanese product of Dolwoe and Korean-roasted products of Dolwoe were analysed and compared. Dolwoe-leaf tea had high mineral content of Ca, Mg, Mn and Cu, while Dolwone-stem tea had high mineral content of K, Na and Fe. Especially in the ash of Dolwoe-stem tea showed the highest mineral content of K (33.4%) Dolwoe teas were extracted for 5 minutes as ratio of $1,000m{\ell}$ boiling water to 4g Dolwoe tea (250: 1, v/w). Comparing the ratio of extraction of minerals in Dolwoe tea made by us and marketed Dolwoe products, K was the most abundant element of all extractions with the rate of $83.2%{\sim}96.3%$ followed by Mg with $44.8%{\sim}62.2%$, Ca with $23.1%{\sim}64.4%$ and Na with $6.3%{\sim}55.6%$. On the other hand Mn, Fe and Cu were extracted in extremely small quantities.

• Korean journal of food and cookery science
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• v.4 no.1
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• pp.53-57
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• 1988

To obtain basic data for the development of domestic tea manufacture, the physico-chemical properties were analyzed. The content of crude fiber in domestic black tea was abundant of 50%, as compared with those in Sri-Lanka's black tea, while the contents of tanin and caffeine were lower than those of Sri-Lanka's Products. The quantities of mineral in Sri-Lanka's products were determined as 300ppm P, 15,000ppm K, 1,400ppm Mg, 4,000ppm Ca, 22ppm Cu, 21ppm Cr and 45ppm Zn. These contents were higher than those of domestic products. Al content was 4,100ppm in domestic products. Pb and Cd were not detected in two kinds of black tea products. In Sri-Lanka's black tea, 8 kinds of organic acids were identified and the major organic acids were shikimic, citric and quinic acid, while 6 kinds of organic acids were identified in domestic products and were quinic and gallic acid, as the major organic acids. The content of sucrose was higher than that of Sri-Lanka's product and theaflavin, thearubigin and theobromine were abundant, as compared with those in domestic products.

• Korean Journal of Food Science and Technology
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• v.22 no.3
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• pp.296-299
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• 1990

As an improved preparation method of Shikhae, a tea-bag system containing malt and amylolytic enzymes was developed in which extraction of malt enzymes and saccharification occured efficiently. The amylolytic activity of the malt was increased by adding the mixture of ${\alpha}-amylase$, glucoamylase and glucoisomerase. Malt and the mixture of enzymes were placed in tea-bag $(16{\times}20cm)$, extracted in water at $30-40^{\circ}C$ for 1-2 hours and followed by saccharification of the cooked rice at $60-70^{\circ}C$ for 3-4 hours. In the conventional Shikhae, content of maltose was about 50% and that of oligosaccharides larger than trisaccharides was about 40% of total sugar. The content of monosaccharides such as glucose and fructose was about 95% and this improved method would be effective for increasing the sweetness and the monosaccharide contents in the product.

• Journal of the Korean Society of Food Culture
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• v.36 no.3
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• pp.300-307
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• 2021

In this study, consumers' perception and consumption behavior of blended tea were investigated. Also, consumer perception of Siberian chrysanthemum, consumption behavior, and awareness of efficacy were investigated. As a result of the survey, it was confirmed that it was necessary to develop a blended tea with taste and flavor characteristics that consumers prefer, having the capability of relieving stress, and preventing cold or respiratory disease. In addition, the degree of recognition of Siberian chrysanthemum was very low, and the recognition of the efficacy appeared in the order of 'cold relief' and 'respiratory disease relief'. Factor analysis results, safety attributes, health attributes, product attributes, marketing attributes, and sensory attributes were factorized into five factors, and after analysis, it was concluded that the sensory attributes of taste and aftertaste were considered the most important. Consumers surveyed appeared to consume blended tea for 'relieving mood or stress relief', to enjoy the taste, and to prevent cold or respiratory diseases. Siberian chrysanthemum displays efficacy in cold relief and relief of respiratory diseases. Therefore, developing Siberian chrysanthemum as a blended tea could be a practical application that can expand the range of its use, making it more popular and increase its commercial applications.

• Natural Product Sciences
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• v.28 no.3
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• pp.121-129
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• 2022

Despite considerable efforts, cancer remains an aggressive killer worldwide. Chemotherapeutic drugs that are currently in use lead to destructive side effects and have not succeeded in fulfilling expectations. For centuries, medicinal plants are used for treating various diseases and are also known to have anticancer activity. The main aim of this research was to evaluate antiproliferative activity of saffron, clove, fenugreek, and green tea on Vero and MDA-MB-231 cell lines and to subsequently analyze the effect of these extracts on IRAK-4, TAK1, IKK-alpha, IKK-beta, NF-Kappa B, IRF3, IRF7 genes in Toll Like Receptors (TLRs) pathway. Antiproliferative assay was done by Neutral Red Dye uptake assay. Methanolic extract of green tea was found to be most effective against both cell lines as IC₅₀ was achieved at least concentration of the extract. For molecular studies, MDAMB-231 cells were sensitized with methanolic extract of green tea at same IC₅₀, and RT-PCR was performed to determine the relative expression of genes. Expression of IRAK-4, TAK1, IKK-beta, NF-Kappa B, IRF3 genes was down regulated and IRF7 and IKKalpha was upregulated. Green tea has a potential cytotoxic effect on both cell lines which was demonstrated by its effect on the expression of (TLRs) pathway genes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.7
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• pp.1108-1113
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• 2003

We performed this study to determine the effect of green tea on jejunal crypt survival, endogenous spleen colony formation, and apoptosis in jejunal crypt cells of mice irradiated with high and low dose of gammairradiation. The radioprotective effect of green tea was compared with the effect of diethyldithiocarbamate (DDC). Jejunal crypts were protected by pretreatment of green tea (p<0.01). Green tea administration before irradiation resulted in an increase of the formation of endogenous spleen colony (p<0.05). The frequency of radiation-induced apoptosis in intestinal crypt cells was also reduced by pretreatment of green tea (p<0.05). The radioprotective effect on jejunal crypts and apoptosis in the DDC treated group appeared similar to those in the green tea treated groups. Treatment with DDC showed no significant modifying effects on the formation of endogenous spleen colony. These results indicated that green tea might be a useful radioprotector, especially since it is a relatively nontoxic natural product. Further studies are needed to characterize better the promotion nature of green tea and its components.