• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.4
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• pp.381-391
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• 1993

To evaluate the antioxidizing effect of flavonoid on fish oil and peroxidized fish oil, rats were fed with diets containing 5% corn oil (CO), 5% corn oil and 15% fresh fish oil (FO) or peroxidixed fish oil (PFO) for 4weeks. An half of FO and PFO group rats were injected with 10mg flavonoid (+)-catechin (a day per kg body weight) (FO-C and PFO-C). FO and FO-C group rats showed higher increase in body weight as compared to PFO, PFO-C group rats. Whereas, the opposite result was obtained in case of liver weight increase. In addition, catechin apparently reduced liver weight by 12~17%. Phospholipid, cholesterol, triglyceride and lipid peroxide content in serum and cholesterol, lipid peroxide content in liver and adipose tissue of PFO, PFO-C group rats were significantly higher than those of FO, FO-C one. These results suggested that catechin reduced the synthesis of lipid and protected effectively against lipid peroxidation. In fatty acids profile of neutral lipid and phospholipid, the ratio of polyunsaturated fatty acids (PUFA) versus saturated fatty acids (SFA) in PFO, PFO-C were lower than that of FO or FO-C because of ruduced PUFA. Contrary to our expectation, the enzyme activities of superoxide dismutase(SOD), catalase and glutathione peroxidase (GSH-Px) in rat liver of FO and FO-C group were lower than those of PFO and PFO-C group. These results were quite interesting and might be explained in terms of homeostasis. In case of total lipid in liver, $C_{20:5}$, $C_{22:6}$ fatty acids were decreased in rat fed peroxidized fish oil. In conclusion, catechin was considered to be an antioxidative and hepatoprotective drug and hypolipidemic agent.

• YAKHAK HOEJI
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• v.43 no.3
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• pp.334-341
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• 1999

Thyroid peroxidase is a biochemical target protein for the antithyroid drugs. Ethanol extracts from one hundred and thirty seven natural products were screened for the inhibition of thyroid peroxidase activity. Thyroid peroxidase was purified from porcine thyroids, and the inhibition of peroxidase activity was evaluated using guaiacol oxidation (C-C coupling) assay. Twenty one natural products expressed a remarkable inhibition (>50%) of peroxidase activity at $330{\mu\textrm{g}}$ solid weight/m. The 50% inhibitory concentration ($IC_{50}$) of 70% ethanol extract from six potent natural products ranged from 3.1 to $31.2{\;}{\mu\textrm{g}}$ solid weight/m, in contrast to the range ($0.33~0.54{\;}{\mu\textrm{g}}/ml$) of $IC_{50}$ values fro catechin and epigallocatechin gallate as positive controls. Noteworthy, the extract of Camellia taliensis showed irreversible inhibition of the enzyme. It is suggested that extract from some natural products such as Camellia taliensis, Rheum undulatum or Euphorbia perinensis, exhibiting a potent inhibition of peroxidase activity, may be developed as sources of potent antithyroid agents.

• Journal of Microbiology and Biotechnology
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• v.28 no.5
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• pp.679-687
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• 2018

Korean red pine (Pinus densiflora) is one of the major Pinus species in Korea. Red pine bark is removed prior to the chipping process in the wood industry and discarded as waste. However, red pine bark contains a considerable amount of naturally occurring phenolics, including flavonoids, and therefore may have a variety of biological effects. In this study, we investigated if Korean red pine bark extract (KRPBE) could protect neuronal PC-12 cells from oxidative stress and inhibit cholinesterase activity. Analysis of reversed-phase high-performance liquid chromatography results revealed four phenolics in KRPBE: vanillin, protocatechuic acid, catechin, and taxifolin. The total phenolic and flavonoid contents of KRPBE were 397.9 mg gallic acid equivalents/g dry weight (DW) and 248.7 mg catechin equivalents/g DW, respectively. The antioxidant capacities of KRPBE measured using ABTS, DPPH, and ORAC assays were 697.3, 521.8, and 2,627.7 mg vitamin C equivalents/g DW, respectively. KRPBE and its identified phenolics protected against $H_2O_2$-induced oxidative cell death in a dose-dependent manner. Acetylcholinesterase and butyrylcholinesterase, which degrade the neurotransmitter acetylcholine to terminate neurotransmission in synaptic clefts, were inhibited by treatment with KRPBE and its identified phenolics. Taken together, these results suggest that KRPBE and its constituent antioxidative phenolics are potent neuroprotective agents that can maintain cell viability under oxidative stress and inhibit cholinesterase activity.

• Bulletin of the Korean Chemical Society
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• v.29 no.9
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• pp.1717-1722
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• 2008

The 70 kDa heat-shock protein (Hsp70) involved in various cellular functions, such as protein folding, translocation and degradation, regulates apoptosis in cancer cells. Recently, it has been reported that the green tea flavonoid (−)-epigallocatechin 3-gallate (EGCG) induces apoptosis in numerous cancer cell lines and could inhibit the anti-apoptotic effect of human Hsp70 ATPase domain (hATPase). In the present study, docking model between EGCG and hATPase was determined using automated docking study. Epi-gallo moiety in EGCG participated in hydrogen bonds with side chain of K71 and T204, and has metal chelating interaction with hATPase. Hydroxyl group of catechin moiety also participated in metal chelating hydrogen bond. Gallate moiety had two hydrogen bondings with side chains of E268 and K271, and hydrophobic interaction with Y15. Based on this docking model, we determined two pharmacophore maps consisted of six or seven features, including three or four hydrogen bonding acceptors, two hydrogen bonding donors, and one lipophilic. We searched a flavonoid database including 23 naturally occurring flavonoids and 10 polyphenolic flavonoids with two maps, and myricetin and GC were hit by map I. Three hydroxyl groups of B-ring in myricetin and gallo moiety of GC formed important hydrogen bonds with hATPase. 7-OH of A-ring in myricetin and OH group of catechin moiety in GC are hydrogen bond donors similar to gallate moiety in EGCG. From these results, it can be proposed that myricetin and GC can be potent inhibitors of hATPase. This study will be helpful to understand the mechanism of inhibition of hATPase by EGCG and give insights to develop potent inhibitors of hATPase.

• Preventive Nutrition and Food Science
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• v.19 no.1
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• pp.40-48
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• 2014

Laver is one of the most consumed edible red algae seaweeds in the genus Porphyra. Laver is primarily prepared in the form of dried, roasted, and seasoned products. We investigated the total polyphenol and flavonoid contents of laver products, and evaluated the in vitro antioxidant properties of solvent extracts from commercially processed laver products. Significant differences in the concentration of phenolic compounds were found among differently processed laver. The total phenolic content for laver extracts ranged from 10.81 mg gallic acid equivalent (GAE)/g extract to 32.14 mg GAE/g extract, depending on extraction solvent and temperature. Laver extracts contained very few flavonoids (0.55 mg catechin equivalent/g extracts to 1.75 mg catechin equivalent/g extracts). 2,2-Diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS), hydroxyl radical, and superoxide anion scavenging assays were used to determine the radical scavenging capacities of laver extracts. These assays revealed that the processing method and extraction condition affected the antioxidant potentials of laver. Antioxidant activity of dried laver, roasted laver, and seasoned laver increased in a concentration-dependent manner ($100{\sim}1,000{\mu}g/mL$). The radical scavenging activities of $37^{\circ}C$ and $100^{\circ}C$ water extracts were lower than that of a $37^{\circ}C$ 70% ethanol extract. The highest radical scavenging capacity was observed in the $37^{\circ}C$ 70% ethanol extracts of dried laver, roasted laver, and seasoned laver. Overall, these results support that notion that laver contains bioactive compounds, such as polyphenols and flavonoids, which may have a positive effect on health.

• Korean Journal of Pharmacognosy
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• v.46 no.1
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• pp.1-5
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• 2015

In the course of screening tyrosinase inhibitory activity, EtOAc-soluble fraction of Nelumbinis Semen (Seeds of Nelumbo nucifera) showed significant inhibition. Further fractionation of the EtOAc-soluble fraction resulted in 12 compounds, which were identified as 4-(hydroxymethyl)phenol (1), tyrosol (2), 4-(hydroxymethyl)benzaldehyde (3), 4-hydroxybenzoic acid (4), 4-(2-methoxyvinyl)benzene-1,2-diol (5), 2,6-dihydroxybenzoic acid (6), (2R-trans)-2,3-dihydro-3,5,7,8-tetrahydroxy-2-(4-hydroxyphenyl)-4H-1-benzopyran-4-one (7), (+)-catechin (8), elephantorrhizol (9), (+)-dehydrovomifoliol (10), (-)-boscialin (11) and uridine (12). Compounds 5 and 7 were first reported from this plant. Among the isolated compounds, compound 7 showed strong inhibition on tyrosinase activity with mixed mechanism of competitive and noncompetitive inhibition.

• Land and Housing Review
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• v.10 no.2
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• pp.45-51
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• 2019

The purpose of this study was to examine the performance of formaldehyde removal from building materials using catechin contained in ginkgo leaf. A small chamber method was used to set up one control group and three experimental groups. As a result, it showed a reduction of formaldehyde from at least 73.5% to 77% when it was increased by 0.4g compared to the control (0g). In addition, it was confirmed by linear regression analysis that the amount of ginkgo leaf and the amount of formaldehyde emission were negatively correlated. Therefore, it was confirmed that the amount of formaldehyde emission was affected by ginkgo leaf.

• Journal of Applied Biological Chemistry
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• v.53 no.2
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• pp.87-90
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• 2010

This study consisted of a quantitative analysis of five phenolic ingredients in differently sized unripe apple extracts, and their tyrosinase inhibitory effects were examined. In the HPLC analysis of phenolic ingredients, small ($4{\pm}1\;g$ per one) unripe apple extracts were observed to have significantly higher quercetin content than larger ($8{\pm}1\;g$ per one) unripe apple and ripe apple extracts. The amount of catechin, epicatechin, p-coumaric acid and chlorogenic acid contents were similar in both the small and large unripe apple extracts. For the results of the tyrosinase assay, small unripe apple extracts provided a potent tyrosinase inhibitory effect, showing 89.2% at 1000 ppm. The tyrosinase inhibitory effects of large unripe apple and ripe apple extracts were weaker than those of the small unripe apple extract. These results suggest that the small unripe apple extract could be useful for de-pigmenting material, while quercetin could be responsible for the potent tyrosinase inhibitory properties of small unripe apple extracts.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.7
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• pp.1079-1084
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• 2004

The present study was conducted to compare antioxidant activity of green teas, fermented teas and other related common teas by examining radical scavenging activity using DPPH (2,2 diphenyl l-picryl hydrazyl). Scavenging activity ($SC_{50}$/) of epigallocatechin gallate (EGCG) for 0.1 mM DPPH radical was 5.5 $\mu$M or 4.2 mg/L by weight, then catechin, 14 $\mu$M or 2.5 mg/L and vitamin C, 22 $\mu$M or 3.9 mg/L, respectively. Kyokuro tea (okro) powder of 24.2 mg/L or green tea powder of 25.2 mg/L was used to reach $SC_{50}$/ for 0.1 mM DPPH. One serving of 2 g green tea provides antioxidant activity equivalent to 109∼147 mg EGCG, 145∼185 mg catechin or 131∼168 mg vitamin C. Teas from the first harvest had the highest radical scavenging activity when compared with later harvest green teas grown in the same region, but there is virtually no difference by the harvest time. A Chinese green tea, Dragon well had the highest antioxidant activity among other green teas tested providing antioxidant capacity equivalent to 168 mg EGCG or 188 mg vitamin C per 2 g serving, but partially fermented Chinese teas had much lower antioxidant activity than any green tea tested. Black tea which is fully fermented showed as strong antioxidant activity as green teas (76.3 mg vs 86.7∼67.6 mg per tea bag). One tea bag of green teas from market provided antioxidant capacity equivalent to 52∼86 mg EGCG, 70∼105 mg catechin or 63-96 mg vitamin C. Teas made of persimmon leaf, pine needle, mulberry leaf had comparatively low anti-oxidant activity equivalent to 2.5∼4.8 mg EGCG or 15∼21 mg vitamin C per teabag. The third brewed green tea still had enough antioxidant activity, while tea from tea bag brewed for 3 min or 5 min did not have any difference in their antioxidant activity. More systemic studies are needed to clarify the relationship between tea catechins and antioxidant capacity focusing on how growing, harvest time, fermentation and other processes can influence on this.

• Food Science of Animal Resources
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• v.38 no.5
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• pp.889-900
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• 2018

Characterization and utilization of the bioactive compounds from natural resources is one of the most concerns to maintain quality properties of foods, especially to prevent the oxidation of lipids in meat products. Phytochemical components and antioxidant activities of Cudrania tricuspidata (CT) leaves extracted using various solvents and their effects on physicochemical properties of pork patties during refrigerated storage were measured. The combined solvents of 80% ethanol, 80% methanol and pure double-distilled (dd)-water obtained the higher total phenolic compounds, flavonoids content, and antioxidant activities as compared to the pure solvent alone. Among the individual antioxidant components, catechin was the predominant polyphenol in CT leaves in all extracts. The addition of CT leaves extracts into pork patties showed high antioxidant activities since thiobarbituric acid-reactive substances (TBARS) values of added CT extracts were lower than those of the control (p<0.05). In conclusion, CT leaf phytochemical components displayed antioxidant activity that varied with the extract solvent used. CT extracts were superior to control in retarding lipid oxidation of pork patties, which was evident as reduced TBARS and peroxide values (POV).