• 제목/요약/키워드: Natural inhibitors

검색결과 537건 처리시간 0.029초

Aldose Reductase Inhibitory Activity of Methanol Extracts from the Korean Plants

  • Jung, Sang-Hoon;Lim, Soon-Sung;Lee, Sang-Hyun;Lee, Yeon-Sil;Shin, Kuk-Hyun;Kim, Yeong-Shik
    • Natural Product Sciences
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    • 제9권1호
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    • pp.34-37
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    • 2003
  • We examined methanol extracts prepared from the Korean plants for their inhibitory effects on rat lens aldose reductase (RLAR) activity in vitro. Among 41 plant extracts, the extracts of Lagerstroemia indica, Punica granatum, Eurya japonica, Liquidambar styraciflua, and Vitis coignetiae exhibited highest inhibitory potency, even more potent than tetramethylene glutaric acid (TMG), known as one of typical aldose reductase inhibitors $(IC_{50}\;value,\;0.51\;{\mu}g/ml)$. Especially, the extract of Lagerstroemia indica (Lythraceae), exhibited the most inhibitory potency $(IC_{50}\;value,\;0.069\;{\mu}/ml)$ on RLAR.

Suppressive effects on the expression of cyclooxygenase-2 and inducible nitric oxide synthase by a natural sesquiterpenoid in lipopolysaccharide-stimulated mouse macrophage cells

  • Min, Hye-Young;Park, Hyen-Joo;Park, Eun-Jung;Lee, Sang-Kook
    • 한국응용약물학회:학술대회논문집
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    • 한국응용약물학회 2003년도 Annual Meeting of KSAP : International Symposium on Pharmaceutical and Biomedical Sciences on Obesity
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    • pp.101-101
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    • 2003
  • Prostaglandins (PGs) and nitric oxide (NO) produced by inducible cyclooygenase (COX-2) and nitric oxide synthase (iNOS), respectively, have been implicated as important mediators in the process of inflammation and carcinogenesis. On this line, the potential COX-2 or iNOS inhibitors have been considered as anti-inflammatory and cancer chemopreventive agents. In our continuing efforts of searching for novel cancer chemopreventive agents from natural products, we isolated natural sesquiterpenoids as potential COX-2 and iNOS inhibitors in cultured lipopolysaccharide (LPS)-activated mouse macrophage RAW 264.7 cells. Alantolactone, a natural eudesmane-type sesquiterpenoid, exhibited a potent inhibition of COX-2 (IC50 = 0.4 $\mu\textrm{g}$/$m\ell$) and iNOS activity (IC50 = 0.08 $\mu\textrm{g}$/$m\ell$) in the assay system determined by PGE2 and NO accumulation, respectively. The inhibitory potential of alantolactone on the PGE2 and NO production was well coincided with the suppression of COX-2 and iNOS protein and mRNA expression in LPS-induced macrophages. Furthermore, alantolactone inhibited NF-kB but not AP-l binding activity on nuclear extracts evoked by LPS-stimulated macrophage cells, suggesting the possible involvement of NF-kB in the regulation of COX-2 and iNOS expression. In further study with COX-2-expressing human colon HT-29 cells, alantolactone inhibited the cell proliferation, down-regulated COX-2, and inhibited the ERK phosphorylation in the early time. These results suggest that a natural sesquiterpenoid alantolactone might be a potential lead candidate for further developing COX-2 or iNOS inhibitor possessing cancer chemopreventive or anti-inflammatory activity

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In vitro 실험법에 의한 천연물 중의 UVB 광독성 억제제 검색 (In vitro Screening of Natural Product Inhibitors on the UVB Phototoxicity)

  • 김현진;이경아;김봉희
    • 한국식품위생안전성학회지
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    • 제17권4호
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    • pp.188-192
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    • 2002
  • 소염효과를 나타내는 생약 15종을 선별하여 이들 생약 추출물이 Chloropromazine에 의한 UVB 광독성에 미치는 영향을 in vitro 실험법 중 Candida albicans test, RBC photohemolysis, MTT assay에 의한 cytotoxicity 측정법의 방법을 이용하여 조사하였다. Candidal albicans teat에 의해 광독성의 광량 및 화학물질 의존성을 관찰할 수 있었으며, 광독성 억제 효과를 검색하기에 적당한 UVB조사량 및 CPZ농도는 2.1 J/$\textrm{cm}^2$, 0.6mg인 것으로 생각되었다. Candida albicans test에 의해 CPZ에 의한 UVB 광독성에는 P. persica, E. officinalis가 억제효과를 보임을 알 수 있었으며, RBC photohemolysis 결과 모든 생약시료들에 대해 hemolysis가 감소되었으며, 특히, Yeast, P. suffruticosa에 의한 % hemolysis는 34.42$\pm$1.01, 35.30$\pm$4.7로 유의성 있는 억제효과를 나타냄을 관찰할 수 있었다. MTT assay에 의한 cytotoxicity 측정 결과, UVB 조사에 이하여 세포생존율은 감소되었고, 시료처리시 세포생존율은 증가됨을 관찰할 수 있었다.

Inhibitory effects of resveratrol analogs on lipopolysaccharide-induced cyclooxygenase-2 activity in RAW264.7 cells

  • Park, Eun-Jung;Min, Hye-Young;Park, Jae-Eun;Kim, Sang-Hee;Lee, Sang-Kook
    • 대한약학회:학술대회논문집
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    • 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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    • pp.245.1-245.1
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    • 2002
  • It has been known that resveratrol, a phytoalexin present in grapes mainly, has antioxidant. anti-inflammatory, and cancer chemopreventive activity. One mechanism of its anti-inflammation and cancer prevention is considered to modulate cyclooxygense-2 (COX-2) activity. Since COX-2 plays an important role in inflammation and carcinogenesis, the potential COX-2 inhibitors have been considered as anti-inflammatory or cancer chemopreventive agents. (omitted)

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Natural Products Targeting Wnt/β-catenin Signaling Pathway

  • Kim, Donghwa;Lee, Sang Kook
    • Natural Product Sciences
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    • 제26권2호
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    • pp.109-117
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    • 2020
  • The canonical Wnt/β-catenin signaling pathways play an important role in the embryonic development, cell proliferation, differentiation, and adhesion. Therefore, the abnormal activation and repression have been associated with uncontrolled homeostasis in human tissues. In particular, the activation of Wnt signaling is highly correlated with a diverse of diseases including cancer. On this regard, a strategy for targeting Wnt/β-catenin signaling has been employed in the discovery and development of antitumor agents. Herein, the evolution of Wnt signaling and the Wnt inhibitors derived from natural products were briefly summarized in the drug discovery of anticancer agents.

섬유소분해균인 Trichoderma의 群體生長의 유도에 관하여 (Induction of Colonial Growth of the Cellulolytic Fungus, Genus Trichoderma)

  • 박희문;홍순우;하영칠
    • 미생물학회지
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    • 제22권3호
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    • pp.143-150
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    • 1984
  • The effect of growth inhibitors on colonial growth of cellulolytic fungus, genus Trichoderma, was investigated to develop a method for the effective screening of various auxotrophs and hypercellulolytic strains. As the results, it was revealed that non-ionic detergents such as Sodium deoxycholate and Triton X-100 were the better ones as a growth inhibitor than Oxgall which has been used to restrict the colony size in genus Trichoderma. Each individual colony remained distinct on minimal plate supplemented with 0.05% Triton X-100 for as long as two or more weeks. The screening of 150 to 200 colonies simultaneous on a single plate was possible in the presence of Triton X-100. The effect of Triton X-100 on simultaneous screening was higher than that of Oxgall by a factor of two.

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3D QSAR Study on Pyrrolopyrimidines-Based Derivatives as LIM2 Kinase Inhibitors

  • Balasubramanian, Pavithra K.;Balupuri, Anand;Cho, Seung Joo
    • 통합자연과학논문집
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    • 제8권4호
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    • pp.285-292
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    • 2015
  • LIM kinases belong to the serine/Threonine kinase family. The members of the LIM kinase (LIMK) family include LIMK 1 and 2 which are involved in the regulation of actin polymerisation and microtubule disassembly. LIMK1 was shown to be involved in cancer metastasis, while LIMK2 activation promotes cells cycle progression. Since LIMK2 plays a vital role in many disease conditions such as pulmonary hypertension, cancer and viral diseases, and till date there are not much selective inhibitors been reported, LIMK2 becomes an interesting therapeutic target among the kinases. 3D QSAR study was carried out on a series of pyrrolopyrimidines based derivatives as LIMK2 inhibitors. A reasonable CoMFA ($q^2$=0.888; ONC=3; $r^2$=0.974) with good statistical values was developed. The developed model was validated using 1000 runs of boostrapping and was found to be predictable. The results of CoMFA contour map analysis suggested that the bulky substitution at $R_4$ and $R_5$ position are highly desirable to increase the activity. Similarly, positive substitution at $R_3$ position is also required to increase the activity. It is also noted that bulky substitution at $R_1$ position must be avoided. Our results could provide valuable information to enhance the activity of the LIMK2 inhibitors and to design potent pyrrolopyrimidines derivatives.

Tyrosinase Inhibitors Isolated from the Edible Brown Alga Ecklonia stolonifera

  • Kang, Hye-Sook;Kim, Hyung-Rak;Byun, Dae-Seok;Son, Byeng-Wha;Nam, Taek-Jeong;Choi , Jae-Sue
    • Archives of Pharmacal Research
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    • 제27권12호
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    • pp.1226-1232
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    • 2004
  • Extracts from seventeen seaweeds were determined for tyrosinase inhibitory activity using mushroom tyrosinase with L-tyrosine as a substrate. Only one of them, Ecklonia stolonifera OKAMURA (Laminariaceae) belonging to brown algae, showed high tyrosinase inhibitory activity. Bioassay-guided fractionation of the active ethyl acetate (EtOAc) soluble fraction from the methanolic extract of E. stolonifera, led us to the isolation of phloroglucinol derivatives [phloroglucinol (1), eckstolonol (2), eckol (3), phlorofucofuroeckol A (4), and dieckol (5)]. Compounds 1~5 were found to inhibit the oxidation of L-tyrosine catalyzed by mushroom tyrosinase with $IC_{50}$ values of 92.8, 126, 33.2, 177, and 2.16 ${\mu}g$ /mL, respectively. It was compared with those of kojic acid and arbutin, well-known tyrosinase inhibitors, with $IC_{50}$ values of 6.32 and 112 ${\mu}g$ / mL, respectively. The inhibitory kinetics analyzed from Lineweaver-Burk plots, showed compounds 1 and 2 to be competitive inhibitors with $K_i$ of $2.3{\times}10^{-4}\;and\;3.1{times}10^{-4}$ M, and compounds 3~5 to be noncompetitive inhibitors with $K_i$ of $1.9{\times}10^{-5},\;1.4{\times}10^{-3}\;and\;1.5{\times}10^{-5}$ M, respectively. This work showed that phloroglucinol derivatives, natural compounds found in brown algae, could be involved in the control of pigmentation in plants and other organisms through inhibition of tyrosinase activity using L-tyrosine as a substrate.

Inhibition of matrix metalloproteinases: a troubleshooting for dentin adhesion

  • de Moraes, Izadora Quintela Souza;do Nascimento, Ticiano Gomes;da Silva, Antonio Thomas;de Lira, Lilian Maria Santos Silva;Parolia, Abhishek;de Moraes Porto, Isabel Cristina Celerino
    • Restorative Dentistry and Endodontics
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    • 제45권3호
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    • pp.31.1-31.20
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    • 2020
  • Matrix metalloproteinases (MMPs) are enzymes that can degrade collagen in hybrid layer and reduce the longevity of adhesive restorations. As scientific understanding of the MMPs has advanced, useful strategies focusing on preventing these enzymes' actions by MMP inhibitors have quickly developed in many medical fields. However, in restorative dentistry, it is still not well established. This paper is an overview of the strategies to inhibit MMPs that can achieve a long-lasting material-tooth adhesion. Literature search was performed comprehensively using the electronic databases: PubMed, ScienceDirect and Scopus including articles from May 2007 to December 2019 and the main search terms were "matrix metalloproteinases", "collagen", and "dentin" and "hybrid layer". MMPs typical structure consists of several distinct domains. MMP inhibitors can be divided into 2 main groups: synthetic (synthetic-peptides, non-peptide molecules and compounds, tetracyclines, metallic ions, and others) and natural bioactive inhibitors mainly flavonoids. Selective inhibitors of MMPs promise to be the future for specific targeting of preventing dentin proteolysis. The knowledge about MMPs functionality should be considered to synthesize drugs capable to efficiently and selectively block MMPs chemical routes targeting their inactivation in order to overcome the current limitations of the therapeutic use of MMPs inhibitors, i.e., easy clinical application and long-lasting effect.