• Title/Summary/Keyword: inhibitory mechanism

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20(S)-ginsenoside Rg3 inhibits glycoprotein IIb/IIIa activation in human platelets

  • Kwon, Hyuk-Woo
    • Journal of Applied Biological Chemistry
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    • v.61 no.3
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    • pp.257-265
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    • 2018
  • The Panax ginseng Mayer is used in conventional medicine in Asia owing to its preventing effects on thrombosis, hypertension, atherosclerosis, vasorelaxation and myocardial infarction. Because platelets are crucial mediators of cardiovascular diseases, many studies have investigated its functions. The previous study showed the antiplatelet effects of crude ginseng fraction and two of its components, ginsenoside Rg3 (20S and 20R). In addition, ginsenoside Rg3-enriched fraction shows an inhibitory effect on collagen-activated rat platelets. However, the mechanism underlying this effect remains unclear. Thus, I investigated the inhibitory action of ginsenoside Rg3 (20S, G-Rg3) on the regulation of signaling molecules involved in ${\alpha}IIb/{\beta}_3$ activation. I found that G-Rg3, in a cyclic AMP dependent manner, inhibited thrombin-induced activation of human platelets and affinity of fibrinogen and fibronectin with ${\alpha}IIb/{\beta}_3$. Thus, in the present study, G-Rg3 showed an inhibitory effect on glycoprotein IIb/IIIa (${\alpha}IIb/{\beta}_3$) activation, suggesting its potential use for preventing platelet-mediated thrombotic disease.

A Mechanism of Gastric Antiulceration by the Extract of Artemisiae asiatica (애엽 추출물의 항위궤양에 대한 기전)

  • Hwang Gwi-Seo;Lee Jung-Suk;Yun Yeo-Pyo
    • Journal of Society of Preventive Korean Medicine
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    • v.1 no.1
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    • pp.118-125
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    • 1997
  • In oriental medicine, Artemisiae asiatica (AA) has been used as analgesic, antiinflammatory agent, and coagulatory agent. Furthermore, eupatilin, a kind of flavonoids, is known as the active principle component of AA. This study was undertaken to determine the gastric antiulceration of AA and to elucidate its mechanism. AA showed the inhibitory effect on gastric ulceration induced by EtOH/HCl and aspirin. To elucidate its mechanism, the effect of AA on lipidperoxide level in gastric mucosa, microsome lipidperoxidation, iron -dependent lipidperoxidation, and neutrophil activation were examined. It is suggested that the antiperoxidative and antineutrophil activity of AA play important roles as a possible mechanism. These results suggest that AA might have gastric antiulceration activity due to antilipidperoxdative and antineutrophil activity.

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The Inhibitory Effects of Nelumbo nucifera Gaertner Extract on Melanogenesis (연자육 추출물의 멜라닌 합성 저해효과)

  • Lee, Jun Young;Im, Kyung Ran;Jung, Taek Kyu;Yoon, Kyung-Sup
    • KSBB Journal
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    • v.28 no.2
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    • pp.137-145
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    • 2013
  • In order to develop new skin whitening agents, we prepared the $CH_2Cl_2$ layer (NGC) and BuOH layer (NGB) of 75% EtOH extract of the Nelumbinis nucifera Gaertner. We measured their tyrosinase inhibitory activity in vitro and melanin synthesis inhibitory activity in B16-F1 melanoma cells. They did not show inhibitory activity against mushroom tyrosinase but showed melanin synthesis inhibitory activity in a dose-dependent manner. In a melanin synthesis inhibition assay, NGC and NGB suppressed melanin production up to 52% and 46% at a concentration of $100{\mu}g/mL$, respectively. To elucidate the mechanism of the inhibitory effects of NGC and NGB on melanogenesis, we measured the expression of melanogenesis-related proteins by western blot assay. As a result, NGC suppressed the expression of tyrosinase, tyrosinase related protein 1 (TRP-1), tyrosinase related protein 2 (TRP-2), phosphorylated cAMP responsive element binding (p-CREB) protein, and microphthalmia associated transcription factor (MITF). And NGB inhibited the protein expression of tyrosinase and MITF, but had no significant effect on TRP-1, TRP-2, and p-CREB expression. Moreover, NGB increased the expression of phosphorylated extracellular signal-regulated kinase (p-ERK). In addition, we examined the inhibitory effect on the glycosylation of tyrosinase. As a result, NGC and NGB inhibited the activity of ${\alpha}$-glucosidase in vitro and the glycosylation of tyrosinase in B16-F1 melanoma cells. From these results, we concluded that NGC and NGB could be used as active ingredients for skin whitening.

Effects of Sochungyong-tang on Cytokine Gene Expression in Mouse Alveolar Macrophage (소청용장(小靑龍湯)이 생쥐의 폐(肺) 대식세포(大食細胞) Cytokine 귀전자(遣傳子) 발현에 미치는 영향)

  • Park, In-Gi;Sim, Sung-Young;Byun, Hak-Sung;Kim, Kyung-Jun
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.18 no.3
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    • pp.1-17
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    • 2005
  • In many recent studies, molecular biological methods have been used to investigate the role of cytokines in pathogenesis of lung disease. This Experiment was conducted to investigate the effects of Sochungyong-tang on gene expressions in Mouse Alveolar Macrophage. Fer this purpose, we observed the cytokines ($IL-1{\beta}$, IL-6, IL-10, iNOS, $MIP-1{\alpha},\;MIP-1{\beta},\;MIP-1{\gamma},\;TGF-{\beta},\;TNF-{\alpha}$). We picked the alveolar macrophage out of mice and cultured it. We analyzed the cytokine gene expression by reverse transcription-PCR. The results obtained were as follows : 1 . Sochungyong-tang showed inhibitory effects on $IL-1{\beta}$ in time and concentration. 2. Sochungyong-tang showed inhibitory effects on IL-6 in time and concentration. 3. Sochungyong-tang showed inhibitory effects on IL-10 in concentration. 4. Sochungyong-tang showed inhibitory effects on iNOS. 5. Sochungyong-tang showed inhibitory effects on $TGF-{\beta}$ in time and concentration. 6. Sochungyong-tang showed on inhibitory effects on $MIP-1{\alpha},\;MIP-1{\beta},\;MIP-1{\gamma}$, $TCF-{\beta}$, $TNF-{\alpha}$. According to above results, it is supposed that Sochungyong-tang has the inhibitory effects on cytokine gene expression in mouse alveolar macrophage and can be usefully applied for curing inflammatory process of lung disease. Advanced studies are required to investigate the cure mechanism of Sochungyong-tang in the future.

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Chemical Composition and Antimicrobial Activity of Essential Oil Extracted from Eucalyptus citriodora Leaf

  • Insuan, Wimonrut;Chahomchuen, Thippayarat
    • Microbiology and Biotechnology Letters
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    • v.48 no.2
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    • pp.148-157
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    • 2020
  • Eucalyptus oil is a rich source of bioactive compounds with a variety of biological activities and is widely used in traditional medicine. Eucalyptus citriodora is cultivated for the production of essential oils. However, the mode of antibacterial action of essential oils from E. citriodora is not well-known. This study aimed to determine the chemical components, microbial inhibitory effect, and mechanism of action of the essential oil from E. citriodora. The oil was extracted from E. citriodora leaves by hydro-distillation and the chemical components were analyzed using gas chromatography-mass spectrometry. The antibacterial activities of eucalyptus oil against gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus, and Staphylococcus intermedius) and gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) were screened by disc diffusion method and quantitative analysis was conducted by the microdilution method. The mechanism of action of the extracted essential oil was observed using SEM and analyzed by SDS-PAGE. The major components of E. citriodora oil were citronellal (60.55 ± 0.07%), followed by dl-isopulegol (10.57 ± 0.02%) and citronellol (9.04 ± 0.03%). The antibacterial screening indicated that E. citriodora oil exhibited prominent activity against all tested strains. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against B. subtilis were 0.5% and 1.0%, respectively. The MIC and MBC concentrations against S. aureus, S. intermedius, E. coli, and P. aeruginosa were 1% and 2%, respectively. As observed by SEM, the antibacterial mechanism of E. citriodora oil involved cell wall damage; SDS-PAGE revealed decrease in protein bands compared to untreated bacteria. Thus, E. citriodora oil showed significant antimicrobial properties and caused cellular damage.

Transcriptome sequencing revealed the inhibitory mechanism of ketoconazole on clinical Microsporum canis

  • Wang, Mingyang;Zhao, Yan;Cao, Lingfang;Luo, Silong;Ni, Binyan;Zhang, Yi;Chen, Zeliang
    • Journal of Veterinary Science
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    • v.22 no.1
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    • pp.4.1-4.13
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    • 2021
  • Background: Microsporum canis is a zoonotic disease that can cause dermatophytosis in animals and humans. Objectives: In clinical practice, ketoconazole (KTZ) and other imidazole drugs are commonly used to treat M. canis infection, but its molecular mechanism is not completely understood. The antifungal mechanism of KTZ needs to be studied in detail. Methods: In this study, one strain of fungi was isolated from a canine suffering with clinical dermatosis and confirmed as M. canis by morphological observation and sequencing analysis. The clinically isolated M. canis was treated with KTZ and transcriptome sequencing was performed to identify differentially expressed genes in M. canis exposed to KTZ compared with those unexposed thereto. Results: At half-inhibitory concentration (½MIC), compared with the control group, 453 genes were significantly up-regulated and 326 genes were significantly down-regulated (p < 0.05). Quantitative reverse transcription polymerase chain reaction analysis verified the transcriptome results of RNA sequencing. Gene ontology enrichment analysis and Kyoto Encyclopedia of Genes and Genomes enrichment analysis revealed that the 3 pathways of RNA polymerase, steroid biosynthesis, and ribosome biogenesis in eukaryotes are closely related to the antifungal mechanism of KTZ. Conclusions: The results indicated that KTZ may change cell membrane permeability, destroy the cell wall, and inhibit mitosis and transcriptional regulation through CYP51, SQL, ERG6, ATM, ABCB1, SC, KER33, RPA1, and RNP genes in the 3 pathways. This study provides a new theoretical basis for the effective control of M. canis infection and the effect of KTZ on fungi.

Effect of phlorotannins isolated from Ecklonia cava on angiotensin I-converting enzyme (ACE) inhibitory activity

  • Wijesinghe, W.A.J.P.;Ko, Seok-Chun;Jeon, You-Jin
    • Nutrition Research and Practice
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    • v.5 no.2
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    • pp.93-100
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    • 2011
  • Inhibition of angiotensin I-converting enzyme (ACE) activity is the most common mechanism underlying the lowering of blood pressure. In the present study, five organic extracts of a marine brown seaweed Ecklonia cava were prepared by using ethanol, ethyl acetate, chloroform, hexane, and diethyl ether as solvents, which were then tested for their potential ACE inhibitory activities. Ethanol extract showed the strongest ACE inhibitory activity with an $IC_{50}$ value of 0.96 mg/ml. Five kinds of phlorotannins, phloroglucinol, triphlorethol-A, eckol, dieckol, and eckstolonol, were isolated from ethanol extract of E. cava, which exhibited potential ACE inhibition. Dieckol was the most potent ACE inhibitor and was found to be a non-competitive inhibitor against ACE according to Lineweaver-Burk plots. Dieckol had an inducible effect on the production of NO in EAhy926 cells without having cytotoxic effect. The results of this study indicate that E. cava could be a potential source of phlorotalnnins with ACE inhibitory activity for utilization in production of functional foods.

Inhibitory Effects of Soamsan1 on Lung Metastasis of B16 Melanoma Cells (B16 흑색종 세포의 폐전이에 대한 소암산1의 억제효과)

  • Jeon Byung Hun;Kim Won Sin
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.16 no.6
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    • pp.1122-1126
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    • 2002
  • We have examined whether Soamsan 1 (SA 1) augment the inhibitory effect of oral administration of Soamsan (SA) on lung metastasis of mouse 816 melanoma cells. The inhibitory effect was slightly enhanced by increase in administration dosage of SA 1. SA 1 as well as SA inhibited effectively the lung metastasis regardless of the pretreatment with anti-mouseNK monoclonal antibody. However, in the case of 2-chloroadenosine-pretreated mice, the inhibitory effects of SA and SA 1 were decreased by 18 and 23%, respectively. In vitro stimulation of the mouse splenocytes with mitogens showed that SA or SA 1 significantly augmented the proliferation of mouse splenocytes. Especially, the activity was more prominent in the presence of a B cell mitogen. LPS than a T cell mitogen, Con A. These results suggest that oral administration of SA 1 or SA inhibited lung metastasis of B16 melanoma cells, possibly through a mechanism mediated by the activation of macrophages and B lymphocytes in the host immune system. However, SA 1 did not showed more significant augment of the activation of immune system than SA.

Conformational Switch and Functional Regulation of Proteins (단백질의 구조 전환과 기능 조절)

  • Yu, Myeong-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11b
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    • pp.3-6
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    • 2001
  • In common globular proteins, the native form is in its most stable state. However, the native form of inhibitory serpins (serine protease inhibitors) and some viral membrane fusion proteins is in a metastable state. Metastability in these proteins is critical to their biological functions. Our previous studies revealed that unusual interactions, such as side-chain overpacking, buried polar groups, surface hydrophobic pockets, and internal cavities are the structural basis of the native metastability. To understand the mechanism by which these structural defects regulate protein functions, cavity-filling mutations of a 1-antitrypsin, a prototype serpin, were characterized. Increasing conformational stability is correlated with decreasing inhibitory activity. Moreover, the activity loss appears to correlate with the decrease in the rate of the conformational switch during complex formation with a target protease. We also increased the stability of a 1-antitrypsin greatly via combining various stabilizing single amino acid substitutions that were distributed throughout the molecule. The results showed that a substantial increase of stability, over 13 kcal/mol, affected the inhibitory activity with a correlation of 11% activity loss per kcal/mol. The results strongly suggest that the native metastability of proteins is indeed a structural design that regulates protein functions and that the native strain of a 1-antitrypsin distributed throughout the molecule regulates the inhibitory function in a concerted manner.

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Inhibitory Actions of Steppogenin on Platelet Activity Through Regulation of Glycoprotein IIb/IIIa and Ca2+ Mobilization (Glycoportein IIb/IIIa와 칼슘동원의 조절을 통한 Steppogenin의 혈소판활성 억제효과)

  • Shin, Jung-Hae;Ha, Ju-Yeon;Kwon, Hyuk-Woo
    • Korean Journal of Pharmacognosy
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    • v.51 no.2
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    • pp.100-106
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    • 2020
  • The extract of Cudrania tricuspidata is used in ethnomedicine throughout Eastern Asia in China, Korea and Japan. In Korean traditional medicine, Cudrania tricuspidata has been used to treat eczema, mumps, tuberculosis, contusions, insomnia and acute arthritis. In addition, it has been reported that root extract of Cudrania tricuspidata has anti-platelet effects. Therefore, we investigated which compound in Cudrania tricuspidata has inhibitory effect on platelet aggregation. In this study, we tried to explain the inhibitory mechanism of steppogenin from Cudrania tricuspidata on human platelet aggregation. Collagen-induced human platelet aggregation and [Ca2+]i mobilization were dose-dependently inhibited by steppogenin and we determined the inhibition by steppogenin is due to the down regulation of extracellular-signal-regulated kinase(ERK) and inositol-1,4,5-triphosphate receptor type I(IP3RI) phosphorylation. In addition, steppogenin inhibited collagen-induced fibronectin adhesion to αIIb/β3 and thromboxane A2 generation. Thus, in the present study, steppogenin showed an inhibitory effect on human platelet aggregation, suggesting its potential use for preventing platelet-induced cardiovascular disease.