• 생명과학회지
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• 제16권3호
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• pp.396-399
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• 2006

고구마(품종: 생미)추출액에 tyrosinase의 활성을 저해하는 저해 물질이 존재함을 확인하였으며, 고구마 추출물의 첨가농도를 증가시킬수록 tyrosinase 활성의 저해도가 증가하였다. 그리고 고구마 추출물에 존재하는 tyrosinase 저해제는 $95^{\circ}C$에서 20분간 열처리에 의하여 37.3%의 활성이 잔존하여 열에 비교적 안정하였으며, pH 5.0-7.0에서 가장 안정하였다. 그리고 고구마 추출물은 투석에 의하여 tyrosinase에 대한 저해활성이 유의적으로 감소하였으며, 따라서 고구마 추출물에 존재하는 tyrosinase의 저해활성은 저분자 물질로 추정된다.

• 생약학회지
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• 제35권4호통권139호
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• pp.271-275
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• 2004

Distylium racemosum Sieb. Et Zucc contains some compounds inhibit -amylase activity in experimental conditions. The inhibitory test showed that 50% acetone extracts from the bark and leaves of the plant strongly inhibited salivary -amylase activity. Proanthocyanidin(PA) which has strong inhibitory activity was extracted from the leaves by chromatography on Sephadex LH-20. The inhibitory activities and the inhibition kinetics of the PA were studied against three kinds of enzymes: human salivary ${\alpha}-Amylase$ (SAA), pork pancreatin ${\alpha}-Amylase$ (PAA) and yeast ${\alpha}-Glucosidase$ (AG). Then the activities of PA against SAA, PAA and AG were compared with those of acarbose, a commercial agent. The inhibitory activities of PA were stronger than those of acarbose. Inhibition kinetics of the PA showed competitive inhibition for SAA and PAA, and non competitive inhibition for GA.

• Journal of Applied Biological Chemistry
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• 제53권2호
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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.

• Asian Pacific Journal of Cancer Prevention
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• 제16권15호
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• pp.6317-6325
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• 2015

Ginkgo biloba extract (GBE) is a popular phytomedicine and has been used for disorders of the central nervous system, cardiovascular, renal, respiratory, and circulatory diseases. Although GBE is a complex mixture of over 300 compounds, its major components are 24% flavonoids and 6% terpene lactones. In this study, we tested the inhibitory effects of the three major flavonoids (kaempferol, quercetin, and isorhamnetin) from GBE, independently and as mixtures, on aromatase activity using JEG-3 cells (human placental cells) and recombinant proteins (human placental microsome). In both systems, kaempferol showed the strongest inhibitory effects among the three flavonoids; the flavanoid mixtures exerted increased inhibitory effects. The results of exon I.1-driven luciferase reporter gene assays supported the increased inhibitory effects of flavonoid mixtures, accompanied by suppression of estrogen biosynthesis. In the RT-PCR analysis, decreased patterns of aromatase promoter I.1 mRNA expressions were observed, which were similar to the aromatase inhibition patterns of flavonoids and their mixtures. The present study demonstrated that three flavonoids synergistically inhibit estrogen biosynthesis through aromatase inhibition, decrease CYP19 mRNA, and induce transcriptional suppression. Our results support the usefulness of flavonoids in adjuvant therapy for breast cancer by reducing estrogen levels with reduced adverse effects due to estrogen depletion.

• Preventive Nutrition and Food Science
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• 제11권4호
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• pp.261-267
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• 2006

This study investigated the physiological activities of different molecular weight (MW) fractions of crude polysaccharide from $D\check{o}d\check{o}k$ (Codonopsis lanceolata). The crude polysaccharide cut off for each fraction was: <1,000 MW (Fr I), 1,000 MW

• Horticulture, Environment, and Biotechnology : HEB
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• 제59권6호
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• pp.899-907
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• 2018

The methanol extracts of flowers obtained from 67 plant species were screened for their inhibitory activity on aldose reductase (AR). Alnus japonica, Aster spathulifolius, Chionanthus retusus, Morus bombycis, Crysanthemum boreale, Persicaria tinctoria, Platycarya strobilacea, and Serratula coronata var. insularis exhibited potent aldose reductase inhibitory (ARI) activity. HPLC-UV analysis of quercetin, an AR inhibitory flavonoid, was performed on extracts showing strong ARI activity. Quercetin was detected in C. retusus, C. boreale, P. tinctoria, and S. coronata var. insularis at concentrations of 1.33, 1.56, 0.82, and $3.37mg\;g^{-1}$ extract, respectively, indicating that quercetin contributed to the ARI activity of these extracts. In the samples in which quercetin was absent, other compounds may be responsible for their potent ARI activity. These results serve as a basis for further studies regarding the bioactive components responsible for the inhibitory effects of various flower extracts on AR activity.

• Journal of Microbiology and Biotechnology
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• 제30권4호
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• pp.552-560
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• 2020

Human carbonic anhydrase (CA) isozyme II has been used as protein target for disorder treatment including glaucoma. Current clinically used sulfonamide-based CA inhibitors can induce side effects, and so alternatives are required. This study aimed to investigate a natural CA inhibitor from Murraya paniculata. The previously developed yeast-based assay was used to screen 14 compounds isolated from M. paniculata and identified by NMR analysis for anti-human CA isozyme II (hCAII) activity. Cytotoxicity of the compounds was also tested using the same yeast-based assay but in a different cultivation condition. Two flavonoid candidate compounds, 5, 6, 7, 8, 3', 4', 5'-heptamethoxyflavone (4) and 3, 5, 7, 8, 3', 4', 5'-heptamethoxyflavone (9), showed potent inhibitory activity against hCAII with a minimal effective concentration of 10.8 and 21.5 μM, respectively, while they both exhibited no cytotoxic effect, even at the highest concentration tested (170 μM). The results from an in vitro esterase assay of the two candidates confirmed their hCAII inhibitory activity with IC₅₀ values of 24.0 and 34.3 μM, respectively. To investigate the potential inhibition mechanism of compound 4, in silico molecular docking was performed using the FlexX and SwissDock software. This revealed that compound 4 coordinated with the Zn²⁺ ion in the hCAII active site through its methoxy oxygen at a distance of 1.60 Å (FlexX) or 2.29 Å (SwissDock). The interaction energy of compound 4 with hCAII was -13.36 kcal/mol. Thus, compound 4 is a potent novel flavonoid-based hCAII inhibitor and may be useful for further anti-CAII design and development.

• International Journal of Oral Biology
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• 제44권4호
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• pp.152-159
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• 2019

The oral care probiotic strain Weissella cibaria CMU (oraCMU) inhibits volatile sulphur compounds associated with halitosis, presumably by inhibiting the growth of associated oral pathogens. In the present study, we investigated whether oraCMU inhibits the production of these compounds by suppressing the expression of mgl. This gene encodes L-methionine-α-deamino-γ-mercaptomethane-lyase (METase) and is involved in the production of methyl mercaptan (CH₃SH) by Porphyromonas gingivalis. Therefore, we specifically investigated the effects of oraCMU on the growth, CH₃SH production, METase activity, and mgl expression of P. gingivalis. The minimum inhibitory concentrations of cell-free supernatant and secreted proteins from oraCMU were 125 mg/mL and 800 ㎍/mL, respectively. At sub-minimum inhibitory concentration levels, these metabolites inhibited CH₃SH production, but they also reduced P. gingivalis viability. Only heat-killed oraCMU decreased CH₃SH production without affecting P. gingivalis viability. Heat-killed oraCMU also inhibited METase activity toward L-methionine and mgl mRNA expression (p < 0.05). In summary, we demonstrated the inhibition of volatile sulphur compounds via the antimicrobial action of oraCMU and, for the first time, the inhibition of such compounds by heat-killed oraCMU, which occurred at the molecular level.

• Archives of Pharmacal Research
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• 제27권10호
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• pp.1043-1047
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• 2004

Thirteen compounds were isolated from the $CH_2Cl_2$ fraction of Machilus thunbergii as phospholipase $C{\Upsilon}1\;(PLC{\Upsilon}1)$ inhibitors. These compounds were identified as nine lignans, two neolignans, and two flavans by spectroscopic analysis. Of these, 5,7-di-O-methyl-3',4'-methylenated (-)-epicatechin (12) and 5,7,3'-tri-O-methyl (-)-epicatechin (13) have not been reported previously in this plant. In addition, seven compounds, machilin A (1), (-)-sesamin (3), machilin G (5), (+)-galbacin (9), licarin A (10), (-)-acuminatin (11) and compound 12 showed dose-dependent potent inhibitory activities against $PLC{\Upsilon}1$ in vitro with $IC_{50}$ values ranging from 8.8 to 26.0 ${\mu}M$. These lignans, neolignans, and flavans are presented as a new class of $PLC{\Upsilon}1$ inhibitors. The brief study of the structure activity relationship of these compounds suggested that the benzene ring with the methylene dioxy group is responsible for the expression of inhibitory activities against $PLC{\Upsilon}1$. Moreover, it is suggested that inhibition of $PLC{\Upsilon}1$ may be an important mechanism for an antiproliferative effect on the human cancer cells. Therefore, these inhibitors may be utilized as cancer chemotherapeutic and chemopreventive agents.

• 한국약용작물학회지
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• 제27권3호
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• pp.208-217
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• 2019

Background: In the present study, we identified two cytotoxic compounds from the root of Rumex crispus L. using a bioassay-based method. Methods and Results: Compared with the other fractions, the diethyl ether ($Et_2O$) fraction of R. crispus root extract exhibited the strongest of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging effect [scavenging concentration 50% $(SC_{50})=63.8{\pm}1.47{\mu}g/m{\ell}$], nitric oxide (NO) production inhibitory effect on the mouse macrophage cell line RAW264.7 [inhibitory concentration 50% $(IC_{50})=60.9{\pm}7.52{\mu}g/m{\ell}$] and cytotoxicity effect on the human hepatoma cell line, HepG2 [lethal concentration 50% $(LC_{50})=115.4{\pm}1.86{\mu}g/m{\ell}$]. According to the bioassay-based method, two cytotoxic compounds were purified from the $Et_2O$ fraction by using column chromatography and preparative high performance liquid chromatography (prep-HPLC). These two compounds were identified as parietin and chrysophanol by using nuclear magnetic resonance (NMR) and liquid chromatography quadruple time of flight mass spectrometry (LC-QTOF-MS). In addition, both parietin and chrysophanol exhibited a cytotoxicity effect on HepG2 cells, their $LC_{50}$ values were $169.1{\pm}17.67{\mu}M$ and $111.5{\pm}6.62{\mu}M$, respectively. Conclusions: Parietin and chrysophanol isolated from the $Et_2O$ fraction of the R. crispus root extract showed cytotoxicity in HepG2 cell.