• Preventive Nutrition and Food Science
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• v.9 no.2
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• pp.156-160
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• 2004

This study aims to investigate the changes in the lipid composition and angiotensin-converting enzyme activity in serum of rats exposed to microwave radiation, and to examine improving effects of green tea catechin to the lipid composition. The microwave-exposed rats received the normal and one of 3 diets: catechin free (MW-0C), 0.25% catechin (MW-0.25C) or 0.5% catechin (MW-0.5C). Rats were sacrificed 6th day after microwave radiation (2.45 ㎓, 15 min). The concentration of serum triglyceridein MW-0C group was increased by 85%, compared with the normal group, but that of MW-0.25C group with 0.25% catechin supplementation was to 17% lower, compared with the MW-0C group. There was no significant difference between normal group and MW-0.5C group. Total-cholesterol and LDL-cholesterol concentrations were increased by 21.4% and 38.6%, respectively, by microwave irradiation. The concentration of HDL-cholesterol in MW-0C group was lower to 29.3%, but it was maintained at the normal level by catechin supplementation. There was no significant difference among four groups in HLD-cholesterol/LDL-cholesterol. Atherogenic index in MW-0C group was increased by 56%, compared with the normal group. Angiotensin-converting enzyme (ACE) activity in lung tissue of MW-0C group was increased by 59 %, while that of MW -0.25C and MW -0.5C group were maintained at the normal level. ACE activity of MW-0C group in serum was increased by 122.8%, compared with the normal group. Catechin supplementation group was significantly reduced, compared with the MW-0C group ACE activity. In conclusion, microwave irradiation increased the serum triglyceride and cholesterol concentrations and ACE activity which are considered as the blood pressure increasing agents. However, catechin supplementation decreased the level of triglyceride, total cholesterol, LDL cholesterol, and ACE activity, which maybe consider catechin as being agent of lowering effect for blood lipid profile for athero-genesis.

• Natural Product Sciences
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• v.17 no.3
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• pp.212-215
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• 2011

In the course of screening anti-adipogenic activity of natural products employing the preadipocyte cell line, 3T3-L1 as an in vitro assay system, the EtOAc fraction of the stem barks of Acer tegmentosum Maxim (Aceraceae) showed significant inhibitory activity on adipocyte differentiation as assessed by measuring fat accumulation using Oil Red O staining. Activity-guided fractionation led to the isolation of active constituent, (+)-catechin. (+)-Catechin showed inhibitory activity on adipocyte differentiation in dose-dependent manner. Further studies with interval treatment demonstrated that (+)-catechin exerted inhibitory activity on adipocyte differentiation via acting on early stage of adipogenesis. Our present study also showed that (+)-catechin significantly inhibited the preadipocyte proliferation. Taken together, these results suggest that (+)-catechin, a constituent of A. tegmentosum might contribute the anti-adipogenic activity of A. tegmentosum.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1203-1206
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• 2008

Silk fibroin (SF) film containing catechin was prepared and the antimicrobial activity as well as physical property of the film was examined. Tensile strength of the SF film decreased with increasing concentration of catechin, and water vapor permeability of the film decreased. The film's antimicrobial activity against Escherichia coli O157:H7 increased with increasing catechin concentration. Sausage samples were inoculated with E. coli 0157:H7 and Listeria monocytogenes, and the sausage packaged with the SF film containing catechin had a decrease in the populations of E. coli O157:H7 and L. monocytogenes by 0.83 and 0.85 log CFU/g after 12 days of storage, respectively, compared to the control. In addition, the sausage had a better quality than the control regarding lipid oxidation. Our results indicate that sausages can be packed with the SF film containing catechin to extend shelf life.

• Journal of the Korean Wood Science and Technology
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• v.38 no.4
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• pp.359-374
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• 2010

This study was carried out to investigate the chemotaxonomical correlation and chemical constituents of domestic Quercus spp. barks. The barks of Q. mongolica, Q. aliena, Q. serrata, Q. acutissima, Q. dentata, and Q. variabilis were collected in the experimental forest of Kangwon National University. The combined extracts were successively fractionated with n-hexane, methylene chloride and ethyl acetate using a separation funnel. A portion of the ethyl acetate and H2O soluble materials of each species were chromatographed on a Sephadex LH-20 column using various aqueous MeOH and EtOH-hexane as washing solvents. Spectrometric analysis such as NMR and MS, including TLC, were performed to characterize the structures of the isolated compounds. Ellagic acid (0.03 g), (+)-catechin (4.59 g), taxifolin (3.35 g), and glucodistylin (20.52 g) were isolated from Q. mongolica bark. Gallic acid (0.18 g), (+)-catechin (8.52 g), (+)-gallocatechin (0.09 g), taxifolin (0.54 g), and glucodistylin (3.28 g) were characterized from Q. acutissima bark. Gallic acid (0.38 g), ellagic acid (0.11 g), (+)-catechin (2.01 g), (+)-gallocatechin (0.12 g), and glucodistylin (0.39 g) were identified from Q. dentata bark. Ellagic acid (1.51 g), (+)-catechin (21.91 g), and glucodistylin (3.91 g) were purified from Q. aliena bark. Ellagic acid (0.84 g), (+)-catechin (0.82 g), taxifolin (4.02 g), and glucodistylin (21.50) were isolated from Q. serrata bark. Gallic acid (0.24 g), caffeic acid (0.05 g), (+)-catechin (0.32 g), and glucodistylin (0.65 g) were purified from Q. variabilis bark. (+)-Catechin and glucodistylin were isolated from all the barks. Glucodistylin can be a taxonomic index on Quercus spp.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.9
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• pp.1095-1100
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• 2008

Antioxidative and macrophage phagocytic activities and contents of functional component in selected Korean chestnuts (Dantaek, Daebo, Okkwang, Seokchu, Byunggo) were evaluated. Coumarin, gallic acid and catechin in inner skin and whole kernel of selected Korean chestnuts were detected by HPLC. The predominant functional components in inner skin of chestnut were catechin, followed by gallic acid and coumarin. However, the whole kernel had only gallic acid. Thus, the antioxidant properties of gallic acid and catechin were evaluated through DPPH radical-scavenging activity and SOD like activity. Gallic acid and catechin at 6.0 mg/100 g exhibited 69.4% and 38.3% of scavenging activities on DPPH radical, respectively. DPPH radical-scavenging activity of gallic acid increased in a concentration-dependent manner. Gallic acid was found to possess higher DPPH radical-scavenging activity than equivalent amount of catechin at all concentrations, whereas catechin was found to have higher SOD like activity than gallic acid. In addition, pre-incubation of macrophage with white kernel extract from Byunggo resulted in a significant increase of phagocytic activity and yellow kernel extracts from Byunggo, Dantaek, Daebo and Okkwang, leading to an increase in phagocytic activity compared with untreated cells. Yellow kernel extracts was found to have higher phagocytic activity than white kernel extracts. Byunggo had the highest phagocytic activity. The results suggest that the Korean chestnut may provide a natural source of antioxidants and active immunity.

• Korean Journal of Food Science and Technology
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• v.35 no.2
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• pp.266-271
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• 2003

Insoluble polyphenol antioxidants, quercetin and catechin, were stabilized through the complexation with cyclodextrin to increase heat and pH stabilities. Comparison of inclusion complex formabilities of quercetin and catechin with ${\alpha}-,\;{\beta}-$, and ${\gamma}-CDs$ revealed ${\beta}-CD$ to be the most suitable result. Optimal molar mixing ratio of ${\beta}-CD$ and quercetin or catechin for inclusion complex formation was found to be 1 : 1. Inclusion complexation was confirmed using differential scanning calorimetry. Solubility of ${\beta}-CD-antioxidant$ inclusion complexes increased compared with native antioxidants, Stability against temperature and pH of ${\beta}-CD-antioxidant$ inclusion complex analyzed revealed antioxidant activities of ${\beta}-CD-quercetin$ and catechin inclusion complexes have higher stabilization compare to raw quercetin and catechin. Peroxide value of linoleic acid dissolved in water decreased substantionally after using ${\beta}-CD-quercetin$ inclusion complex. ${\beta}-CD-antioxidant$ inclusion complex can be used effectively as a fresh-food preservative.

• Journal of Nutrition and Health
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• v.32 no.7
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• pp.838-843
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• 1999

Antitumor effects of various teas have been studied for a long time. Among them, green tea is one of the most popular test and very close to our lives in Korea. However, precise effect and mechanism about antitumor effects of green tea were not estabilished. The present study investigated the antitumor effect of catechin, which is main component of green tea, which was produced in Korea, was used. In each group, morphological changes were observed induced severe cell damage and growth inhibition gradually until 24hours. Then catechin effect was found to be concentration-and time-dependent. EATC was injured abruptly at 100ug/ml catechin treatment for 6 hours and the effect lasted constantly until 24 hours. But in both of cell lines, cell damage and inhibition of proliferation did not show up apparently at concentration of 10 and 1ug/ml. In contrast, catechin led to little or no effect against HepG2 in all of concentrations and periods. These results suggest that catechin extracted from green tea had different effect on cancer cells as cell type, concentration and period. Therefore green tea would be helpful to cancer treatment as well as cancer prevention and this study would be the basic source for further research of green tea.

• Journal of the Korean Wood Science and Technology
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• v.28 no.3
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• pp.62-69
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• 2000

The bark of ash(Fraxinus rhynchophylla) and elm(Ulmus davidiana var. japonica) trees were collected, extracted with acetone-$H_2O$(7:3, v/v), fractionated with hexane, chloroform and ethylacetate, and freeze dried to give some dark brown powder. Each fraction of the powder was chromatographed on a Sephadex LH-20 column using a series of aqueous methanol and ethanol-hexane mixture as eluents. The ash bark contained a large amount of coumarin derivatives such as aesculetin and aesculin in addition to trace amount of ligstroside and oleuropein. Most of the elm bark extractive were (+)-catechin and its glycosides such as (+)-catechin-7-O-xylopyranose and (+)-catechin-7-O-apiofuranose in addition to a small amount of procyanidin B-3, a dimeric (+)-catechin. NMR and FAB-MS spectrometric analyses were performed to characterize the structures of isolated phenolic compounds.

• The Korean Journal of Food And Nutrition
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• v.10 no.1
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• pp.74-81
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• 1997

In this study, we tried to figure out how phenol effects on cancer prevention, and for this purpose we focused on phenol effects on TBARS and the relationship between TBARS(thiobarbituric acid-reactive substances) and cancer. A protocol using a nutritionally adequate amino acid-based diet and a transgenic mouse model of neurofibromatosis was used to evaluate the effect of dietary phenols on body tissue oxidation and tumor onset. The mice carry the human T-lymphotropic virus type-1 transactivator(texl) gene and spontaneously develop externally visible tumors. Twenty-five male transgenic mice were systematically assigned into five groups, control group, 2 mmol, 4 mmol, 8 mmol catechin/kg diet groups and wine solid group. Mice in control group were without catechin, Mice in wine solid group received red wine 750 mL/kg diet, Mice were examined daily, and the age at which a first tumor appeared was recorded. Transgenic mice consuming catechin and wine solid were older when a first tumor appeared. No tumor was found in one mouse of 4 mmol catechin/kg diet and one mouse of 8 mmol catechin diet group. Levels of TBARS in brain and spleen of 8 mmol catechin group and wine solid group were significantly decreased as compared to the same tissue in control group. TBARS levels in tissues were significantly correlated with tumor onset. Results from this study suggest that dietary phenol effects on cancer prevention through tissue antioxidation in spite of different kinds of phenols.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.3
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• pp.409-416
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• 2007

This study investigated changes in the catechin and alkaloid contents of Bosung green tea during different manufacturing processes and storage periods, using HPLC and UV-VIS spectrophotometer analysis. For changes in the catechin and alkaloid contents by roasting technique, we found that EGCG, CG and GCG decreased just slightly by processes performed before roasting, rather than after roasting. In addition, theobromine, caffeine, and ECG changed minimally throughout all the processes. For changes in the catechin and purine alkaloid contents of the green tea leaves during storage, EGCG, ECG, and CAF decreased considerably in the green tea stored at temperatures of $5^{\circ}C$ and $25^{\circ}C$, and they decreased by $20{\sim}30%$ after storage for 1 year. However, a quantitative difference was hardly observed in the catechin and alkaloid contents regardless of storage temperature.