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High Throughput Screening for Natural Products to Find Biologically Active Compounds : Natural Products versus Combinatorial Chemistry

  • Sankawa, Ushio
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1997.11a
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    • pp.47-50
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    • 1997
  • Drug development began with the finding of biologically active compounds which are obtained by chemical synthesis or from natural sources. The advent of Combinatorial Chemistry is recognized as a strategy which has a potential to change the methodology of research and development(R&D) of new drugs. Drug development has been carried out with diverse strategies. In the past several decades a variety of new methodology have been introduced in R&D. Random screening of accumulated synthetic samples which had been synthesized for development of other drugs led to the discovery of new drugs. The typical examples are anti-asthma drug trimethoquinol and calcium antagonist diltiazem. (herbesser). In particular the latter drug has been used as a calcium antagonist worldwide, however it was first synthesized to find new tranquilizer and this is the reason why diltiazem has benzodiazepam skeleton. The random screening contributed in the finding of new drugs were carried out with whole animal test and it is a standard methodology in R&D of new drugs. Aspirin is the first synthetic non-steroidal antiinflammatory drug(NSAID) and has been used for more than one hundred years. It is the first example of drug developed from natural product. Salicin is the main constituent of willow bark which had been used in Europe for a long time to treat arthritis and aspirin was developed from salicin. Most of NSAID used clinically were developed from the structure of aspirin, however it took 70 years to clarify why aspirin exhibits its antiinflammatory, analgesic and antipyretic activities. The target of aspirin is cyclooxygenase(COX)which is the first enzyme involved in arachidonate cascade leading to the production of prostaglandins(PG) and thromboxan(TX). Side effect of aspirin causing ulcer in stomach is rather serious problem, since aspirin is so popular drug easily obtained in drug store(OTP). This problem is now going to be solved by a new finding on COX, which have two different types, one is constitutionally expressed COX 1 in almost all organs and the other is inducible COX 2. COX 2 is the responsible enzyme in inflammation etc and now the search of COX 2 specific inhibitors is the target of R&D of next generation NSAID.

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G0/G1 Cell Cycle Arrest and Activation of Caspases in Honokiol-mediated Growth Inhibition of Human Gastric Cancer Cells

  • Kang, You-Jin;Chung, Hwa-Jin;Min, Hye-Young;Song, Ja-Young;Park, Hyen-Joo;Youn, Ui-Joung;Bae, Ki-Hwan;Kim, Yeong-Shik;Lee, Sang-Kook
    • Natural Product Sciences
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    • v.18 no.1
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    • pp.16-21
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    • 2012
  • Honokiol, a naturally occurring neolignan mainly found in Magnolia species, has been shown to have the anti-angiogenic, anti-invasive and cancer chemopreventive activities, but the molecular mechanism of actions has not been fully elucidated yet. In the present study, we investigated the effect of honokiol on the growth inhibitory activity in cultured SNU-638 human gastric cancer cells. We found that honokiol exerted potent antiproliferative activity against SNU-638 cells. Honokiol also arrested the cell cycle progression at the G0/G1 phase and induced the apoptotic cell death in a concentration-dependent manner. The cell cycle arrest was well correlated with the downregulation of Rb, cyclin D1, cyclin A, cyclin E, and CDK4 expression, and the induction of cyclin-dependent kinase inhibitor p27. The increase of sub-G1 peak by honokiol was closely related to the induction of apoptosis, which was evidenced by the induction of DNA fragmentation, the cleavage of poly(ADPribose) polymerase, and the sequential activation of caspase cascade. These findings suggest the cell cycle arrest and induction of apoptosis might be one possible mechanism of actions for the anti-proliferative activity of honokiol in human gastric cancer cell.

Enantioconvergent Hydrolysis of Racemic Epoxides for Production of Enantiopure Epoxides and Vicinal Diols using Epoxide Hydrolases (에폭사이드 가수분해효소에 의한 광학수렴반응을 이용한 광학활성 에폭사이드 및 Vicinal Diol 제조)

  • Lee, Eun-Yeol
    • KSBB Journal
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    • v.22 no.3
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    • pp.123-128
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    • 2007
  • One drawback of conventional kinetic resolution of racemic epoxides by epoxide hydrolase (EH) is that the theoretical yield can never exceed 50%. This 50% limitation can be overcome by using enantioconvergent process, in which both enantiomers of the racemic epoxide are transformed via stereochemically matching pathways into a single enantiopure diol as the sole product in 100% theoretical yield. In order to make a single enantiopure vicinal diol, the two enantiomers of the racemic epoxide must be hydrolyzed with retention and inversion of configuration each other. The EHs should be enantio- and regiospecific at the same time. The enantioconvergent hydrolysis with EHs and relevant biotransformation for preparing enantiopure epoxides and vicinal diols with a high yield are reviewed.

(E)-3-(3-methoxyphenyl)-1-(2-pyrrolyl)-2-propenone displays suppression of inflammatory responses via inhibition of Src, Syk, and NF-κB

  • Kim, Yong;Jeong, Eun Jeong;Han Lee, In-Sook;Kim, Mi-Yeon;Cho, Jae Youl
    • The Korean Journal of Physiology and Pharmacology
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    • v.20 no.1
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    • pp.91-99
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    • 2016
  • (E)-3-(3-methoxyphenyl)-1-(2-pyrrolyl)-2-propenone (MPP) is an aldol condensation product resulting from pyrrole-2-carbaldehyde and m- and p- substituted acetophenones. However, its biological activity has not yet been evaluated. Since it has been reported that some propenone-type compounds display anti-inflammatory activity, we investigated whether MPP could negatively modulate inflammatory responses. To do this, we employed lipopolysaccharide (LPS)-stimulated macrophage-like RAW264.7 cells and examined the inhibitory levels of nitric oxide (NO) production and transcriptional activation, as well as the target proteins involved in the inflammatory signaling cascade. Interestingly, MPP was found to reduce the production of NO in LPS-treated RAW264.7 cells, without causing cytotoxicity. Moreover, this compound suppressed the mRNA levels of inflammatory genes, such as inducible NO synthase (iNOS) and tumor necrosis factor (TNF)-${\alpha}$. Using luciferase reporter gene assays performed in HEK293 cells and immunoblotting analysis with nuclear protein fractions, we determined that MPP reduced the transcriptional activation of nuclear factor (NF)-${\kappa}B$. Furthermore, the activation of a series of upstream signals for NF-${\kappa}B$ activation, composed of Src, Syk, Akt, and $I{\kappa}B{\alpha}$, were also blocked by this compound. It was confirmed that MPP was able to suppress autophosphorylation of overexpressed Src and Syk in HEK293 cells. Therefore, these results suggest that MPP can function as an anti-inflammatory drug with NF-${\kappa}B$ inhibitory properties via the suppression of Src and Syk.

Inhibitory Activity of Cordyceps bassiana Extract on LPS-induced Inflammation in RAW 264.7 Cells by Suppressing NF-κB Activation

  • Yoon, Deok Hyo;Han, Changwoo;Fang, Yuanying;Gundeti, Shankariah;Han Lee, In-Sook;Song, Won O;Hwang, Ki-Chul;Kim, Tae Woong;Sung, Gi-Ho;Park, Haeil
    • Natural Product Sciences
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    • v.23 no.3
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    • pp.162-168
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    • 2017
  • Cordyceps bassiana has long been used as an oriental medicine and reported to possess diverse biological activities. The fruiting bodies of Cordyceps bassiana was extracted with ethanol and then further fractionated with n-hexane, ethyl acetate, n-butanol and water. The butanol fraction from Cordyceps bassiana (CBBF) exhibited the most effective in anti-inflammatory activity in RAW 264.7 macrophages and the roles of CBBF on the anti-inflammation cascade in LPS-stimulated RAW 264.7 cells were studied. To investigate the mechanism by which CBBF inhibits NO, iNOS and COX-2, the activation of $I{\kappa}B$ and MAPKs in LPS-activated macrophage were examined. Our present results demonstrated that CBBF inhibits NO production and iNOS expression in LPS-stimulated RAW 264.7 macrophage cells, and these effects were mediated through the inhibition of $I{\kappa}B-{\alpha}$, JNK and p38 phosphorylation. Also, CBBF suppressed activation of MAPKs including p38 and SAPK/JNK. Furthermore, CBBF significantly suppressed LPS-induced intracellular ROS generation. Its inhibition on iNOS expression, together with its antioxidant activity, may support its anti-inflammatory activity. Thus Cordyceps bassiana can be used as a useful medicinal food or drug for further studies.

Apoptotic Effects and Mechanism Study of Scopoletin in HepG2 Cells (Scopoletin의 간암세포에 대한 고사 유도 효과 및 기전 연구)

  • Kwon Kang-Beom;Kim Eun-Kyung;Park Sung-Joo;Song Ho-Joon;Lee Young-Rae;Park Byung-Hyun;Park Jin-Woo;Ryu Do-Gon
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.19 no.6
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    • pp.1594-1598
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    • 2005
  • Scopoletin (6-methoxy-7-hydrorycournarin) is a phenolic coumarin and a member of the phytoalexins. In this study we investigated whether scopoletin causes apoptosis in human hepatoma HepG2 cells and, if so, by what mechanisms. We report that scopoletin induced apoptosis as confirmed by a chromatin condensation. The signal cascade acivated by scopoletin included the activation of caspase-3 as evidenced by increased pretense activity. Activation of caspase-3 resulted in the cleavage of 116 kDa poly(ADP-ribose) polymerase (PARP) to 85 kDa cleavage product in a dose-dependent fashion. Also, scopoletin-induced apoptotic mechanism of HepG2 cells involved the generation of hydrogen peroxide. Taken together, these results suggest that scopgletin induces hydrogen peroxide generation, which, in turn, causes activation of caspase-3, degradation of PARP, and eventually leads to apoptotic cell death in HepG2 cells.

Korean Red Ginseng saponin fraction modulates radiation effects on lipopolysaccharide-stimulated nitric oxide production in RAW264.7 macrophage cells

  • Lee, Young Ji;Han, Jeong Yoon;Lee, Chang Geun;Heo, Kyu;Park, Se Il;Park, Yoo Soo;Kim, Joong Sun;Yang, Kwang Mo;Lee, Ki-Ja;Kim, Tae-Hwan;Rhee, Man Hee;Kim, Sung Dae
    • Journal of Ginseng Research
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    • v.38 no.3
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    • pp.208-214
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    • 2014
  • Background: In previous work, we reported that Korean Red Ginseng saponin fraction (RGSF) showed anti-inflammatory activities in vitro and in vivo. Methods: The present study investigated the radioprotective properties of RGSF by examining its effects on ionizing radiation (IR)-enhanced and lipopolysaccharide (LPS)-mediated inflammatory responses in murine macrophage cells. Results: RGSF induced strong downregulation of IR-enhanced and LPS-induced proinflammatory responses such as nitric oxide (NO) production (Inhibitory Concentration $50(IC_{50})=5.1{\pm}0.8{\mu}M$) and interleukin-$1{\beta}$ levels. RGSF was found to exert its radioprotective effects by inhibition of a signaling cascade that activated checkpoint kinase 2enuclear factor-${\kappa}B$. In addition, RGSF strongly inhibited IR-enhanced LPS-induced expression of hemoxyganase-1, implying that the latter may be a potential target of RGSF. Conclusion: Taken together, our data suggest that RGSF can be considered and developed for use as an effective radioprotective agent with minimal adverse effects.

Virechana karma (therapeutic purgation) in the restoration of gut microbiota concerning Amavata (RA): A scientific exposition

  • Godbole, Amrit;Sweta, Sweta;Abhinav, Abhinav;Singh, O.P.
    • CELLMED
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    • v.11 no.1
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    • pp.1.1-1.4
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    • 2021
  • Background: Amavata is a disease that occurs as a result of the error of metabolism. Poor dietary habits and faulty Dincharya (daily regimen) and ritucharya (seasonal regimen) leading to deranged metabolism and Agni (metabolic fire) which results in the formation of Ama(undigested product of metabolism). When Amaconceals with Vata(subtle energy associated with movement) and circulates in the body under the influence of Vyana Vayu (omnipresent air)it clogs the srotasas (microchannels) and initiates the inflammatory cascade. Amavata is commonly correlated with rheumatoid arthritis (RA) while other forms of auto-immune disorders can also be included in Amavata.Dysbiosis of the gut microbiota (GM) has been connected to the onset of diverse autoimmune diseases. In this study, it was hypothesized that Panchakarma (bio-purificatory methods) based intervention such as Virechana Karma (therapeutic purgation) may influence microbiota. Materials and Methods: Various Ayurvedic literature were reviewed for the etiopathogenesis of Amavata. Different databases were searched with research papers related to Gut Dysbiosis and autoimmunity and management of RA. A connecting link between Intestinal Dysbiosis with the autoimmune mechanisms was established and it was also found that the bowel cleansing introduced a change to the GM. Conclusion: It was concluded that Virechana karma is effective in gut flora Dysbiosis. This study aims to correlate the ancient Ayurvedic principles related to Agni Bala(metabolic energy) and biopurificatory treatment modalities like Virechana karma (therapeutic purgation)with the modern concept of gut microbiota and its role in the pathogenesis of various autoimmune disorders such as rheumatoid arthritis. The article creates an understanding about principles of Ayurveda and its rationality in today's scientific world and thereby opens newer vistas of research in therapeutics from Ayurveda, which may be helpful in the management of various immune-mediated Diseases through Ayurveda.

Bundled Discounting of Healthcare Services and Restraint of Competition (의료서비스의 결합판매와 경쟁제한성의 판단 - Cascade Health 사건을 중심으로 -)

  • Jeong, Jae Hun
    • The Korean Society of Law and Medicine
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    • v.20 no.3
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    • pp.175-209
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    • 2019
  • The bundled discounting which the dominant undertakings engage in is problematic in terms of competition restraint. Bundled discounts generally benefit not only buyers but also sellers. Specifically, bundled discounts usually costs a firm less to sell multiple products. In addition, Bundled discounts always provide some immediate consumer benefit in the form of lower prices. Therefore, competition authorities and courts should not be too quick to condemn bundled discounts and apply the neutral and objective standard in bundled discounting cases. Cascade Health v. Peacehealth decision starts ruling from this prerequisite. This decision pointed out that the dominant undertaking can exclude rivals through bundled discounting without pricing its products below its cost when rivals do not sell as great a number of product lines. So bundled discounting may have the anticompetitive impact by excluding less diversified but more efficient producers. This decision did not adopt Lepage case's standard which does not require the court to consider whether the competitor was at least as efficient of a producer as the bundled discounter. Instead of that, based on cost based approach, this decision said that the exclusionary element can not be satisfied unless the discounts result in prices that are below an appropriate measures of the defendant's costs. By adopting a discount attribution standard, this decision said that the full amount of the discounts should be allocated to the competitive products. As the seller can easily ascertain its own prices and costs of production and calculate whether its discounting practices exclude competitors, not the competitor's costs but the dominant undertaking's costs should be considered in applying discount attribution standard. This case deals with bundled discounting practice of multiple healthcare services by the dominant undertaking in healthcare market. Under the Korean healthcare system and public health insurance system, the price competition primarily exists in non-medical care benefits because public healthcare insurance in Korea is in combination with the compulsory medical care institution system. The cases that Monopoly Regulation and Fair Trade Law deals with, such as cartel and the abuse of monopoly power, also mainly exist in non-medical care benefits. The dominant undertaking's exclusionary bundled discounting in Korean healthcare markets may be practiced in the contracts between the dominant undertaking and private insurance companies with regards to non-medical care benefits.

Inhibitory Activity of Edible Mushrooms on the Tissue Thromboplastin (Tissue Factor) (조직 혈액응고인자에 대한 식용버섯류의 저해활성)

  • Hwang, Keum-Hee;Kim, Hyun-Ku;Han, Yong-Nam
    • Korean Journal of Food Science and Technology
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    • v.29 no.1
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    • pp.161-166
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    • 1997
  • Tissue thromboplastin (tissue factor), a membrane bound glycoprotein is an important initiating factor in blood coagulation cascade, which leads to the formation of thrombin by activating both factor X and IX. Activation of blood coagulation by TF is essential for blood injury, and stimulates the blood coagulation in myocardial infarction, cancer and blood coagulatory diseases. High density lipoprotein, apolipoprotein A-II were known to be biological TF inhibitors. Recently, studies on search for TF inhibitors from natural products have been active in Korea. Among the edible mushrooms screened for inhibitory activities on the TF, Lentinus edodes showed the most strong activity, followd by Agaricus bisporus and Ganoderma lucidium. And the fractionation of the above mushrooms with the chloroform ($CHCl_3$) and ethylacetate (EtOAc) was done and evaluated for the inhibitory activities on TF. In Ganoderma lucidium, $CHCl_3$ fraction and $H_2O$ layer were not active, but EtOAc fraction exhibited a strong inhibitory activity on TF and the $IC_{50}$ value was $1.07{\times}10^{-4}\;g$. In the case of Agaricus bisporus, there were no inhibitory activities on the TF in all of the fractions. $CHCl_3$ fraction and $H_2O$ layer of Lentinus edodes did not show inhibition on the TF but EtOAc fraction showed strong inhibition on the TF, and the $IC_{50}$ value was $7.70{\times}10^{-4}\;g$.

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