• Title, Summary, Keyword: biological activity

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Structure and Biological Activity of K(H2O)L (L = 5,7-Dihydroxy-6,4'-dimethoxyisoflavone-3'-sulfonate)

  • Guo, Ya-Ning;Zhang, Xue-Ling;Zhang, Zun-Ting
    • Bulletin of the Korean Chemical Society
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    • v.27 no.9
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    • pp.1289-1292
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    • 2006
  • Potassium(I) with 5,7-dihydroxy-6,4'-dimethoxyisoflavone-3'-sulfonate (L) assembles to K($H_2O$)L (L = 5,7-dihydroxy-6,4'-dimethoxyisoflavone-3'-sulfonate). It was characterized by single-crystal X-ray diffraction, element analysis, IR and $^1H$ NMR spectroscopy. It crystallizes in the monoclinic space group $P2_1$/n and reveals a seven-coordinate complex. Polyhedra potassium chains, C-H${\cdot}{\cdot}{\cdot}\pi$ and C-H${\cdot}{\cdot}{\cdot}$O and O-H${\cdot}{\cdot}{\cdot}$O hydrogen bonds lead K($H_2O$)L to a three-dimensional network structure. The biological activity of resistance to hypoxia was tested, and the results showed that the biological activity of resistance to hypoxia of K($H_2O$)L is as good as that of its precursor, irisolidone.

Molecular Orbital Consideration of the Conformation of Chloramphenicol (클로람페니콜의 Conformation에 관한 분자궤도론적 연구)

  • Chae, Yung Bog;Cho Ung In;Jhon Mu Shik
    • Journal of the Korean Chemical Society
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    • v.16 no.6
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    • pp.329-333
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    • 1972
  • Chloramphenicol molecule has an asymmetric carbon, so it has conformational isomer, namely, threo and erythro form. These two forms have great difference in biological activity, that is, only threo (-) form has biological activity. Semiempirical quantum mechanical treatments are applied to these molecules to explain the difference, using the extended Huckel theory. The theoretical predictions for the preferred conformation are in good agreement with the experimental results.

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Biological evaluation of Korean medicinal plants

  • Woo, Won-Sick;Shin, Kuk-Hyun;Kwon, Young-Myung
    • YAKHAK HOEJI
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    • v.16 no.3
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    • pp.121-128
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    • 1972
  • Alcohol extracts of 70 Korean medicinal plants have been tested for their biological activity. Most of the extracts had slight activity only. Some extracts had more pronounced activity. The results are tabulated.

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Water Activity Control in Lipase-catalyzed Reaction System

  • Rhee, Joon-Shick;Kwon, Seok-Joon
    • Journal of Microbiology and Biotechnology
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    • v.8 no.3
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    • pp.191-196
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    • 1998
  • This mini review describes the effects of water activity (${\alpha}_w$) on the kinetics, regio- and enantioselectivities of lipases, and various methods for measuring and controlling ${\alpha}_w$ in lipase catalyzed reaction in organic solvent.

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Elevated RalA activity in the hippocampus of PI3Kγ knock-out mice lacking NMDAR-dependent long-term depression

  • Sim, Su-Eon;Lee, Hye-Ryeon;Kim, Jae-Ick;Choi, Sun-Lim;Bakes, Joseph;Jang, Deok-Jin;Lee, Kyungmin;Han, Kihoon;Kim, Eunjoon;Kaang, Bong-Kiun
    • BMB Reports
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    • v.46 no.2
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    • pp.103-106
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    • 2013
  • Phosphoinositide 3-kinases (PI3Ks) play key roles in synaptic plasticity and cognitive functions in the brain. We recently found that genetic deletion of $PI3K{\gamma}$, the only known member of class IB PI3Ks, results in impaired N-methyl-D-aspartate receptor-dependent long-term depression (NMDAR-LTD) in the hippocampus. The activity of RalA, a small GTP-binding protein, increases following NMDAR-LTD inducing stimuli, and this increase in RalA activity is essential for inducing NMDAR-LTD. We found that RalA activity increased significantly in $PI3K{\gamma}$ knockout mice. Furthermore, NMDAR-LTD-inducing stimuli did not increase RalA activity in $PI3K{\gamma}$ knockout mice. These results suggest that constitutively increased RalA activity occludes further increases in RalA activity during induction of LTD, causing impaired NMDAR-LTD. We propose that $PI3K{\gamma}$ regulates the activity of RalA, which is one of the molecular mechanisms inducing NMDAR-dependent LTD.

Carotenogenesis in Haematococcus lacustris: Role of Protein Tyrosine Phosphatases

  • Park, Jae-Kweon;Tran, Phuong Ngoc;Kim, Jeong-Dong;Hong, Seong-Joo;Lee, Choul-Gyun
    • Journal of Microbiology and Biotechnology
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    • v.19 no.9
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    • pp.918-921
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    • 2009
  • In the present study, we examined the inhibitory effects of protein tyrosine phosphatase (PTPase) inhibitors, including sodium orthovanadate (SOV), ammonium molybdate (AM), and iodoacetamide (IA), on cell growth, accumulation of astaxanthin, and PTPase activity in the photosynthetic algae Haematococcus lacustris. PTPase activity was assayed spectrophotometrically and was found to be inhibited 60% to 90% after treatment with the inhibitors. SOY markedly abolished PTPase activity, significantly activating the accumulation of astaxanthin. These data suggest that the accumulation of astaxanthin in H. lacustris results from the concerted actions of several PTPases.

Inhibition of Melanogenesis by Dioctyl Phthalate Isolated from Nigella glandulifera Freyn

  • Nguyen, Duc T. M.;Nguyen, Dung H.;Hwa-La, Lyun;Lee, Hyang-Bok;Shin, Jeong-Hyun;Kim, Eun-Ki
    • Journal of Microbiology and Biotechnology
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    • v.17 no.10
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    • pp.1585-1590
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    • 2007
  • Although a number of melanogenesis inhibitors have recently been reported and used as cosmetic additives, none is completely satisfactory, leaving a need for novel skin-depigmenting agents. Thus, to develop a novel skin depigmenting agent from natural sources, the inhibition of melanogenesis by Chinese plants was evaluated. A methanolic extract of Nigella glandulifera Freyn was found to inhibit the melanin synthesis of murine B16F10 melanoma cells by 43.7% and exhibited a low cytotoxicity (8.1%) at a concentration of $100\;{\mu}g/ml$. Thus, to identify the melanogenesis-inhibiting mechanism, the inhibitory activity towards tyrosinase, the key enzyme of melanogenesis, was further evaluated, and the results showed inhibitory effects on the activity of intracellular tyrosinase yet not on mushroom tyrosinase. Finally, to isolate the compounds with a hypopigmenting capability, activity-guided isolation was performed, and Dioctyl phthalate identified as inhibiting melanogenesis.

Regulation of m-Calpain Activity by α-Synuclein and Its C-terminal Fragment (α-syn61-140)

  • Lee, In-Hwan;Kim, Hyun-Jin;Lee, Choong-Hwan;Paik, Seung R.
    • Bulletin of the Korean Chemical Society
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    • v.27 no.7
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    • pp.1001-1004
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    • 2006
  • The m-calpain activity hydrolyzing a fluorogenic substrate of N-Succinyl-Leu-Leu-Val-Tyr-7-amino-4-methylcourmarin (LLVY-AMC) was significantly stimulated by more than two-fold in the presence of 5$\mu$M $\alpha$synuclein at $15{^{\circ}C}$. The stimulation was also confirmed with azocasein. The stimulation of the peptide hydrolyzing activity required structural intactness of $\alpha$-synuclein since the C-terminally or N-terminally modified proteins such as $\beta$-synuclein, $\alpha$-syn1-97, and $\alpha$-syn61-140 did not increase the proteolytic activity. Instead, however, the N-terminally truncated $\alpha$-syn61-140 was shown to drastically suppress the calpain activity. Since the N-terminal truncation was known to be the primary cleaving event of calpain-mediated proteolysis of $\alpha$-synuclein and the $\alpha$-syn61-140 has been demonstrated to be resistant against the calpain digestion, it has been proposed that the intracellular calpain activity could be regulated in a reciprocal manner by $\alpha$-synuclein and its proteolyzed C-terminal fragment. Based on the results, a possible physiological function of $\alpha$-synuclein has been suggested as a calpain regulator which contains both stimulatory and inhibitory activities.

Synthesis and Biological Activities of Aklyl Thiosulfi(o)nates (Alkyl thiosulfi(o)nate 화합물의 합성과 생리활성)

  • Jung, Hyun-Jin;Kyung, Kyu-Hang;Jung, Yi-Sook;Kyung, Suk-Hun
    • Applied Biological Chemistry
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    • v.51 no.3
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    • pp.183-187
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    • 2008
  • Alkyl thiosulfi(o)nates, analogs of allyl-2-propene-1-thiosulfinate isolated from Allium sativum and having antibacterial activity, were chemically synthesized and their biological activities were investigated. Alkyl thiosulfinates were prepared by oxidation of corresponding disulfides with organic peroxy acid, while alkyl thiosulfonates could be obtained by oxidation of the alkyl thiosulfinates using sodium periodate. All synthetic thiosulfi(o)nates showed antibacterial activity against Staphylococcus aureus B33 and antifungal activity against Candida utilis ATCC42416. Further more synthetic alkyl thiosulfonates displayed antioxidant activity and have also prevention effect of platelet aggregation induced by collagen in rat.

In Vivo Antifungal Activities of 57 Plant Extracts Against Six Plant Pathogenic Fungi

  • Choi, Gyung-Ja;Jang, Kyoung-Soo;Kim, Jin-Seok;Lee, Seon-Woo;Cho, Jun-Young;Cho, Kwang-Yun;Kim, Jin-Cheol
    • The Plant Pathology Journal
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    • v.20 no.3
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    • pp.184-191
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    • 2004
  • Methanol extracts of fresh materials of 57 plants were screened for in vivo antifungal activity against Magna-porthe grisea, Corticium sasaki, Botrytis cinerea, Phyto-phthora infestans, Puccinia recondita, and Blumeria graminis f. sp. hordei. Among them, seven plant extracts showed disease-control efficacy of more than 90% against at least one of six plant diseases. None of the plant extracts was highly active against tomato gray mold. The methanol extracts of Chloranthus japonicus (roots) (CjR) and Paulownia coreana (stems) (PcS) displayed the highest antifungal activity; the CjR extract controlled the development of rice blast, rice sheath blight, and wheat leaf rust more than 90%, and tomato gray mold and tomato late blight more than 80%. The PcS extract displayed control values of more than 90 % against rice blast, wheat leaf rust, and barley powdery mildew and more than 80% against tomato gray mold. The extract of PcS also had a curative activity against rice sheath blight and that of CjR had a little curative activity against rice blast. On the other hand, the extract of Rumex acetocella roots reduced specifically the development of barley powdery mildew. Further studies on the characterization of antifungal substances in antifungal plant extracts are underway and their disease-control efficacy should be examined under greenhouse and field conditions.