• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.237-246
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• 2015

Purpose: The present study was conducted to reveal the correlation of structural denaturation and decrease of enzyme activity when the antioxidative enzymes, superoxide dismutase (SOD) and catalase (CAT) were repeatedly exposed to UV-B, and further investigate whether the denaturation and inactivation of those enzymes can be effectively blocked by using UV-inhibitory RGP lens. Methods: Each enzyme solution was prepared from the standardized SOD and CAT, and repeatedly exposed to UV-B of 312 nm for 30 minutes, 1 hour and 2 hours a day over 1, 2, 3, 4 and 5 days. Structural denaturation of SOD and CAT induced by repeat UV-B irradiation was confirmed by the electrophoretic analysis, and their enzyme activity was determined by the colorimetric assay using the proper assay kit. At that time, the change in structure and activity of the antioxidant enzymes directly exposed to UV-B was compared to the case that UV-B was blocked by UV-inhibitory RGP lens. Results: SOD exposed repeatedly to UV-B showed the polymerization pattern in the electrophoretic analysis when it repeatedly exposed for 30 min a day, however, the change of its activity was less than 10%. On the other hand, CAT repeatedly exposed to UV-B reduced size and density of the electrophoretic band which indicated a structure denaturation, and its activity was significantly decreased. In the case that the repeat exposure time was longer, CAT activity was completely lost even though some enzyme band occurred in the electrphoretic analysis. In addition, the degeneration of CAT due to UV-B irradiation was inhibited to some extent by using RGP lens with a UV-B blocking of 63.7%, however, it was not completely inhibited. Conclusions: From these results, it was revealed that the structural denaturation of antioxidative enzymes was not perfectly correlated with the reduction in enzyme activity according to the type of enzyme. It is recommended to minimize the exposure time to UV when wearing contact lens, or wear the contact lenses having UV blocking rate of the FDA Class I blocker or the sunglasses having equivalent UV-blocking rate for reducing the damage of antioxidative enzymes induced by UV.

• Journal of Life Science
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• v.22 no.7
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• pp.920-927
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• 2012

The objective of this research was to develop the functional material of water and 60% ethanol extracts from nine kinds of mulberry fruits (Morus alba L.) that influence the inhibitory activity on angiotensin-converting enzyme, xanthine oxidase, ${\alpha}$-amylase, and ${\alpha}$-glucosidase. The total phenolic contents in the water extracts were over 2 mg/g in two species (Cheongilppong and Kangwon III) and five species (Daeyoupchosaeng, Cheongilppong, Kangwon III, Hihak, and Cataneo) of 60% ethanol extracts. The inhibitory activity against the angiotensin-converting enzyme was determined with them. Baekwoon III was $90.9{\pm}4.5%$ in the water extracts, and Hihak was $81.8{\pm}4.5%$ in the 60% ethanol extracts. The inhibitory activity of Kuksang 20 against xanthin oxidase was about 10% in the water extracts, and Cataneo was $21.4{\pm}2.3%$ in the 60% ethanol extracts. Six of the species (Daeyoupchosaeng, Suwonppong, Cheongilppong, Kangwon III, Hihak, and Kuksang 20) in the water extracts showed inhibitory activities against ${\alpha}$-amylase, as 100%, respectively. The inhibitory activity of ${\alpha}$-glucosidase was determined for these nine species. Four species (Baekwoon III, Daeyoupchosaeng, Cheongilppong, Kangwon III, Hihak, and Kuksang 20) in the water extracts and three species (Daechoukmyeun, Kangwon III, and Kuksang 20) in the 60% ethanol extracts showed inhibition of over 20%. The results revealed strong biological activity in spite of little total phenolic contents. These water and 60% ethanol extracts with high-quality biological activity from various mulberry fruits (Morus alba L.) are expected to represent good candidates for the development of antihypertentive and antidiabetes sources.

• Biomedical Science Letters
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• v.19 no.2
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• pp.147-152
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• 2013

17-${\beta}$-hydroxysteroid dehydrogenase type 1 ($17{\beta}$-HSD type 1) mediates the reaction of $17{\beta}$-estradiol (E2) production from estrone (E1). Inhibitory effects of curcuminoids on $17{\beta}$-HSD type 1 activity were investigated to find a lead compound for treating estrogen-dependent diseases including breast cancer. Among curcuminoids, demethoxycurcumin showed potent inhibitory effect ($IC_{50}=2.7{\mu}M$) on mouse $17{\beta}$-HSD type 1. Curcuminoids also displayed their inhibitory effects on the production of $17{\alpha}$-estradiol which is a carcinogenic metabolite produced by the enzyme. Bisdemethoxycurcumin ($IC_{50}=1.3{\mu}M$) showed potent inhibitory effect on the $17{\alpha}$-estradiol production by chicken $17{\beta}$-HSD type 1. Curcuminoids did not inhibit ERE transcriptional activity with and without E2. Taken together, curcuminoids can be used for treating and preventing E2-dependent diseases via inhibition on $17{\beta}$-HSD type 1 activity.

• Food Science and Biotechnology
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• v.16 no.3
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• pp.421-425
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• 2007

The inhibitory effect of onion extract on polyphenol oxidase (PPO) and browning of peach juice was investigated. Various reducing agents such as L-ascorbic acid, L-cysteine, dithiothreitol, glutathione, and sodium pyrosulfite strongly inhibited polyphenol oxidase extracted from peach. The enzyme was also inhibited by addition of water extract of onion. Regardless of substrates used, the addition of heated onion extract exhibited stronger inhibitory effect on peach polyphenol oxidase activity than that of the fresh one. The inhibitory effect of onion extract was dependent on heating temperature and time. The onion extract inhibited the peach polyphenol oxidase non-competitively. The heating of onion extract in the presence of glucose, glycine stimulated the inhibitory effect of the onion extract, which suggests non-enzymatic browning products produced during heating might be responsible for the stronger inhibitory action of the heated onion extract. The retardation of peach juice browning by onion extract seems to be caused by inhibition of peach PPO.

• The Korean Journal of Physiology and Pharmacology
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• v.12 no.2
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• pp.65-71
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• 2008

The present study examined the inhibitory effect of licorice compounds glycyrrhizin and a metabolite $18{\beta}$-glycyrrhetinic acid on the neurotoxicity of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in the mouse and on the 1-methyl-4-phenylpyridinium ($MPP^+$)-induced cell death in differentiated PC12 cells. MPTP treatment increased the activities of total superoxide dismutase, catalase and glutathione peroxidase and the levels of malondialdehyde and carbonyls in the brain compared to control mouse brain. Co-administration of glycyrrhizin (16.8 mg/kg) attenuated the MPTP effect on the enzyme activities and formation of tissue peroxidation products. In vitro assay, licorice compounds attenuated the $MPP^+$-induced cell death and caspase-3 activation in PC12 cells. Glycyrrhizin up to $100{\mu}M$ significantly attenuated the toxicity of $MPP^+$. Meanwhile, $18{\beta}$-glycyrrhetinic acid showed a maximum inhibitory effect at $10{\mu}M$; beyond this concentration the inhibitory effect declined. Glycyrrhizin and $18{\beta}$-glycyrrhetinic acid attenuated the hydrogen peroxide- or nitrogen species-induced cell death. Results from this study indicate that glycyrrhizin may attenuate brain tissue damage in mice treated with MPTP through inhibitory effect on oxidative tissue damage. Glycyrrhizin and $18{\beta}$-glycyrrhetinic acid may reduce the $MPP^+$ toxicity in PC12 cells by suppressing caspase-3 activation. The effect seems to be ascribed to the antioxidant effect.

• Current Research on Agriculture and Life Sciences
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• v.31 no.4
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• pp.227-232
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• 2013

We studied antioxidant activity and inhibitory effect of ${\alpha}$-glucosidase from aqueous, ethanolic and methanolic fractions of Galla rhois. In FRAP and ORAC assay for measuring antioxidant activity, we confirmed that Galla rhois extracts had strong antioxidant activity and ethanolic and methanolic extracts were relatively stronger than aqueous extract. We used trolox as a positive control. In order to measure the inhibitory effect of ${\alpha}$-glucosidase, we compared acarbose and Galla rhois extracts. As a result of ${\alpha}$-glucosidase inhibitory assay, aqueous, ethanolic and methanolic extracts of Galla rhois showed high inhibitory activitity and ethanolic and methanolic extracts were relatively stronger than aqueous extract. The 50% inhibitory concentrations (IC50s) of acarbose, aqueous, ethanolic and methanolic fractions were 0.45 mM, $0.53{\mu}g/ml$, $0.415{\mu}g/ml$ and $0.37{\mu}g/ml$, respectively. These results suggest that Galla rhois extracts can be a clinically useful anti-diabetic ingredient, indicating that it needs to be fractionated and isolated and should be further investigated.

• Microbiology and Biotechnology Letters
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• v.49 no.2
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• pp.167-173
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• 2021

Reactive oxygen species (ROS) disrupt the cellular redox balance, exert cytotoxic effects, and consequently promote the development of various diseases in humans. Previous studies have reported that antioxidants counteract the adverse effects of ROS. Several studies examine the whitening effects of various agents based on their ability to inhibit tyrosinase activity. Tyrosinase is a critical enzyme involved in the synthesis of melanin, which protects the skin against radiation. Various agents exhibiting antioxidant and tyrosinase inhibitory activities have been synthesized. However, these synthetic drugs are associated with toxicity, decreased safety, and poor skin penetration in vivo, which has limited the clinical application of synthetic drugs. This study examined the antioxidant and tyrosinase inhibitory activities of some microalgae. The methanol, dichloromethane, and ethyl acetate extracts of four microalgal species (Tetraselmis tetrathele, Dunaliella tertiolecta, Platymonas sp., and Chaetoceros simplex) were prepared. The physiological and whitening effects of microalgal extracts were investigated by measuring the antioxidant and tyrosinase inhibitory activities. The ethyl acetate extract of D. tertiolecta exhibited the highest antioxidant and tyrosinase inhibitory activities. Future studies must focus on examining the whitening effects of microalgae on cell lines to facilitate the development of microalga-based therapeutics for skin diseases, functional health foods, and whitening agents. Thus, microalgae have potential applications in the pharmaceutical, food, and cosmetic industries.

• Food Science of Animal Resources
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• v.32 no.5
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• pp.652-658
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• 2012

This study was carried out to identify the ACE (Angiotensin converting enzyme) inhibitory activity of casein hydrolysates for development of anti-hypertensive hydrolysates. Sodium caseinate was treated with six kinds of commercial proteases such as Flavourzyme, Protamex, Neutrase 1.5, Alcalase, Protease M, and Protease S for 8 h individually, and was then treated with the enzyme combination for 4 h at $45^{\circ}C$. The hydrolysate which had the highest ACE inhibitory effect was then hydrolysed successively with three digestive enzymes: pepsin, trypsin, and ${\alpha}$-chymotrypsin, at $37^{\circ}C$ for 4 h under conditions mimicking those of the gastrointestinal tract. UF (ultra filtration) treatment was applied to one of the secondary hydrolysates to determine ACE inhibitory activity. When sodium caseinate was hydrolysed by commercial proteases, the degree of hydrolysis (DH) showed 2.54 to 4.25% and after secondary hydrolysis, DH showed 4.30 to 5.22%. ACE inhibitory activity and $IC_{50}$ values decreased, and inhibition rates increased during hydrolysis. Protamex treatment showed the lowest $IC_{50}$ value ($516{\mu}g/mL$) and Flavourzyme hydrolysate showed the highest $IC_{50}$value ($866{\mu}g/mL$). As the first hydrolysate was treated with Flavourzyme, the ACE inhibitory activity increased. Neutrase hydrolysate had the highest activity with an $IC_{50}$ value ($282{\mu}g/mL$). When Neutrase plus Flavourzyme treatment was hydrolyzed by digestive enzymes, the $IC_{50}$ value ($597{\mu}g/mL$) was decreased statistically (p<0.05). As Neutrase plus Flavourzyme hydrolysate is treated by UF with MW cut-off 10,000, permeate showed $273{\mu}g/mL$ of $IC_{50}$ value, showed no difference, but retentate which has over MW 10,000 showed statistically different $IC_{50}$ value, $635{\mu}g/mL$ (p<0.05).

• Journal of the Society of Cosmetic Scientists of Korea
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• v.23 no.3
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• pp.86-91
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• 1997

Some natural polyhydroxy aromatic compounds have inhibitory activity against tyrosinase, key enzyme for formation of melanin pigment. We examined the structure-activity relationship of the natural polyhydrowy aromatic compounds and synthesized a number of new derivetives through various methods. Skin lightening effects of these compounds were examined through inhibition of mushroom tyrosinase and inhibitory of melanogenesis on B-16 melanoma cells. These new compounds showed strong inhibitory activity against tyrosinase. Good lightening effects sue to inhibition of melanogenesis were observed from several resorcinol and pyrogallol derivatives. In toxicological tests such as skin primary irritation and sensitization, the above compounds were sufficiently safe for cosmetic use.

• Korean Journal of Pharmacognosy
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• v.33 no.2 s.129
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• pp.144-150
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• 2002

The methanol extracts of 132 herbal medicines were screened for the inhibitory activity against heparinase enzyme from Flavobacterium heparinum. Eleven medicinal plants, Amomum xanthiodides, Agrimonia pilosa, Paeonia lactiflora, Rubia cordifolia, Sanguisorba officinalis, Torrega grandis, Morus alba, Gleditsia sinensis, Crataegus pinnatifida, Cornus officinalis, Paeonia japonica showed potent inhibition on heparinase activity. The active substituents of those herbal medicine could be extracted into butanol fraction and the inhibitory compounds of Morus alba are now isolating.