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- 저자 : Shehzad, A. (검색결과 94 건)
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Shehzad, Omer,Kim, Hyun Pyo,Kim, Yeong Shik Springer-Verlag 2013 Analytical and bioanalytical chemistry Vol.405 No.13
<P>Ginseng (Panax ginseng C. A. Meyer) has been one of the most popular herbs used for nutritional and medicinal purposes by the people of eastern Asia for thousands of years. Ginsenosides, the mostly widely studied chemical components of ginseng, are quite different depending on the processing method used. A number of studies demonstrate the countercurrent chromatography (CCC) separation of ginsenosides from several sources; however, there is no single report demonstrating a one-step separation of all of these ginsenosides from different sources. In the present study, we have successfully developed an efficient CCC separation methodology in which the flow-rate gradient technique was coupled with a new solvent gradient dilution strategy for the isolation of ginsenosides from Korean white (peeled off dried P. ginseng) and red ginseng (steam-treated P. ginseng). The crude samples were initially prepared by extraction with butanol and were further purified with CCC using solvent gradients composed of methylene chloride-methanol-isopropanol-water (different ratios, v/v). Gas chromatography coupled with flame ionization detector was used to analyze the components of the two-phase solvent mixture. Each phase solvent mixture was prepared without presaturation, which saves time and reduces the solvent consumption. Finally, 13 ginsenosides have been purified from red ginseng with the new technique, including Rg1, Re, Rf, Rg2, Rb1, Rb2, Rc, Rd, Rg3, Rk1, Rg5, Rg6, and F4. Meanwhile, eight ginsenosides have been purified from white ginseng, including Rg1, Re, Rf, Rh1, Rb1, Rb2, Rc, and Rd by using a single-solvent system. Thus, the present technique could be used for the purification of ginsenosides from all types' ginseng sources. To our knowledge, this is the first report involving the separation of ginsenoside Rg2 and Rg6 and the one-step separation of thirteen ginsenosides from red ginseng by CCC.</P>
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Shehzad, O.,Khan, S.,Ha, I.J.,Park, Y.,Tosun, A.,Kim, Y.S. Elsevier 2013 Journal of chromatography A Vol.1310 No.-
The targeted purification of compounds with a broad polarity range from traditional medicinal plants is a big challenge for counter-current chromatography (CCC). Gradient elution was introduced in CCC to address this problem. However, once a suitable solvent system is selected, the separation process requires optimization of operational parameters. The present study was conducted to optimize various operational parameters to integrate the flow rate and solvent gradients for the rapid isolation of eight coumarins from Seseli resinosum in a single run. An increase in the system temperature from 15<SUP>o</SUP>C to 35<SUP>o</SUP>C increased the stationary phase retention and solubility of the sample, whereas the operation time and viscosity of the system were decreased. The high purity of each compound was ensured by collecting the fractions from the main peaks while all the shoulder peaks were mixed and separated under the same conditions with semi-preparative CCC. GC-FID was used to analyze the components of each phase, which was prepared without presaturation to save the time and solvent consumption. Finally, eight coumarins were purified, including (1) d-laserpitin, (2) (3'S,4'S)-3'-angeloyloxy-4'-hydroxy-3',4'-dihydroseselin, (3) (+)-samidin, (4) (3'S,4'S)-3'-acetoxy-4'-angeloyloxy-3',4'-dihydroseselin, (5) deltoin (6), calipteryxin, (7) (3'S,4'S)-3',4'-disenecioyloxy-3',4'-dihydroseselin, and (8) (-)-anomalin. The present technique has successfully accomplished the goal of one-step separation of these compounds with high purity and recovery in an economic and time efficient manner.
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Study of Grains and Boundaries of Molybdenum Diselenide and Tungsten Diselenide Using Liquid Crystal
Shehzad, Muhammad Arslan,Hussain, Sajjad,Lee, Junsu,Jung, Jongwan,Lee, Naesung,Kim, Gunn,Seo, Yongho American Chemical Society 2017 NANO LETTERS Vol.17 No.3
<P>Direct observation of grains and boundaries is a vital factor in altering the electrical and optoelectronic properties of transition metal dichalcogenides (TMDs), that is, MoSe2, and WSe2. Here, we report visualization of grains and boundaries of chemical vapor deposition grown MoSe2 and WSe2 on silicon, using optical birefringence of two-dimensional layer covered with nematic liquid crystal (LC). An in-depth study was performed to determine the alignment orientation of LC molecules and their correlation with other grains. Interestingly, we found that alignment of liquid crystal has discrete preferential orientations. From computational simulations, higher adsorption energy for the armchair direction was found to force LC molecules to align on it, compared to that of the zigzag direction. We believe that these TMDs with three-fold symmetric alignment could be utilized for display applications.</P>
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Ramlibacter terrae sp. nov. and Ramlibacter montanisoli sp. nov., Isolated from Soil
( Shehzad Abid Khan ),( Hyung Min Kim ),( Ju Hye Baek ),( Hye Su Jung ),( Che Ok Jeon ) 한국미생물 · 생명공학회 2021 Journal of microbiology and biotechnology Vol.31 No.9
Two gram-negative, catalase-positive, strictly aerobic, and white colony-forming bacteria, strains H242<sup>T</sup> and B156<sup>T</sup>, were isolated from soil in South Korea. Cells of strain H242<sup>T</sup> were oxidase-positive and non-motile short rods, while those of strain B156<sup>T</sup> were oxidase-negative and long non-motile rods. Ubiquinone-8 was identified as the sole isoprenoid quinone in both strains. C<sub>16:0</sub>, cyclo-C<sub>17:0</sub>, and summed feature 3 (C<sub>16:1</sub> ω7c and/or C<sub>16:1</sub> ω6c) and phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol were identified in both strains as the major cellular fatty acids and polar lipids, respectively. The DNA G+C contents of strains H242<sup>T</sup> and B156<sup>T</sup> were 69.4 mol% and 69.3 mol%, respectively. Phylogenetic analyses based on 16S rRNA and 92 concatenated core gene sequences revealed that strains H242<sup>T</sup> and B156<sup>T</sup> formed distinct phylogenic lineages from other Ramlibacter type strains. The DNA-DNA hybridization (DDH) value between strains H242<sup>T</sup> and B156<sup>T</sup> was 24.6%. Strains H242<sup>T</sup> and B156<sup>T</sup> were most closely related to Ramlibacter ginsenosidimutans BXN5-27<sup>T</sup> and Ramlibacter monticola G-3-2<sup>T</sup> with 98.4% and 98.6% 16S rRNA gene sequence similarities, respectively. Digital DDH values between strain H242<sup>T</sup> and R. ginsenosidimutans and between strain B156<sup>T</sup> and R. monticola were 23.5% and 26.1%, respectively. Phenotypic, chemotaxonomic, and molecular analyses indicated that strains H242<sup>T</sup> and B156<sup>T</sup> represent two novel species of the genus Ramlibacter, for which the names Ramlibacter terrae sp. nov. and Ramlibacter montanisoli sp. nov., respectively, are proposed. The type strains of R. terrae and R. montanisoli are H242<sup>T</sup> (=KACC 21667 <sup>T</sup> =JCM 33922<sup>T</sup>) and B156T (=KACC 21665 <sup>T</sup> =JCM 33920<sup>T</sup>), respectively.
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Shehzad, Adeeb,Lee, Jaetae,Lee, Young Sup Published for International Union of Biochemistry 2013 Biofactors Vol.39 No.1
<P>Curcumin (diferuloylmethane), an active constituent of turmeric, is a well-described phytochemical, which has been used since ancient times for the treatment of various diseases. The dysregulation of cell signaling pathways by the gradual alteration of regulatory proteins is the root cause of cancers. Curcumin modulates regulatory proteins through various molecular mechanisms. Several research studies have provided in-depth analysis of multiple targets through which curcumin induces protective effects against cancers including gastrointestinal, genitourinary, gynecological, hematological, pulmonary, thymic, brain, breast, and bone. The molecular mechanisms of action of curcumin in treating different types of cancers remain under investigation. The multifaceted role of this dietary agent is mediated through its inhibition of several cell signaling pathways at multiple levels. Curcumin has the ability to inhibit carcinogenicity through the modulation of the cell cycle by binding directly and indirectly to molecular targets including transcription factors (NF-kB, STAT3, β-catenin, and AP-1), growth factors (EGF, PDGF, and VEGF), enzymes (COX-2, iNOS, and MMPs), kinases (cyclin D1, CDKs, Akt, PKC, and AMPK), inflammatory cytokines (TNF, MCP, IL-1, and IL-6), upregulation of proapoptotic (Bax, Bad, and Bak) and downregulation of antiapoptotic proteins (Bcl(2) and Bcl-xL). A variety of animal models and human studies have proven that curcumin is safe and well tolerated even at very high doses. This study elaborates the current understanding of the chemopreventive effects of curcumin through its multiple molecular pathways and highlights its therapeutic value in the treatment and prevention of a wide range of cancers.</P>
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Shehzad, Adeeb,Islam, Salman Ul,Ahn, Eun-Mi,Lee, You Mie,Lee, Young Sup Informa UK (Taylor Francis) 2016 Cancer Biology & Therapy Vol.17 No.9
<P>Decursinol angelate (DA), an active pyranocoumarin compound from the roots of Angelica gigas, has been reported to possess anti-inflammatory and anti-cancer activities. In a previous study, we demonstrated that prostaglandin E-2 (PGE(2)) plays a survival role in HL-60 cells by protecting them from the induction of apoptosis via oxidative stress. Flow cytometry and Hoechst staining revealed that PGE(2) suppresses menadione-induced apoptosis, cell shrinkage, and chromatin condensation, by blocking the generation of reactive oxygen species. Treatment of DA was found to reverse the survival effect of PGE(2) as well as restoring the menadione-mediated cleavage of caspase-3, lamin B, and PARP. DA blocked PGE(2)-induced activation of the EP2 receptor signaling pathway, including the activation of PKA and the phosphorylation of CREB. DA also inhibited PGE(2)-induced expression of cyclooxygenase-2 and the activation of the Ras/Raf/ Erk pathway, which activates downstream targets for cell survival. Finally, DA greatly reduced the PGE(2)-induced activation of NF-B p50 and p65 subunits. These results elucidate a novel mechanism for the regulation of cell survival and apoptosis, and open a gateway for further development and combinatory treatments that can inhibit PGE(2) in cancer cells.</P>
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Shehzad, Adeeb,Islam, Salman Ul,Lee, Jaetae,Lee, Young Sup Korean Society for Molecular and Cellular Biology 2014 Molecules and cells Vol.37 No.12
Prostaglandin $E_2$ ($PGE_2$) promotes tumor-persistent inflammation, frequently resulting in cancer. Curcumin is a diphenolic turmeric that inhibits carcinogenesis and induces apoptosis. $PGE_2$ inhibits curcumin-induced apoptosis; however, the underlying inhibitory mechanisms in colon cancer cells remain unknown. The aim of the present study is to investigate the survival role of $PGE_2$ and whether addition of exogenous $PGE_2$ affects curcumininduced cell death. HCT-15 cells were treated with curcumin and $PGE_2$, and protein expression levels were investigated via Western blot. Reactive oxygen species (ROS) generation, lipid peroxidation, and intracellular glutathione (GSH) levels were confirmed using specific dyes. The nuclear factor-kappa B ($NF-{\kappa}B$) DNA-binding was measured by electrophoretic mobility shift assay (EMSA). $PGE_2$ inhibited curcumin-induced apoptosis by suppressing oxidative stress and degradation of PARP and lamin B. However, exposure of cells to the EP2 receptor antagonist, AH6809, and the PKA inhibitor, H89, before treatment with $PGE_2$ or curcumin abolished the protective effect of $PGE_2$ and enhanced curcumin-induced cell death. $PGE_2$ activates PKA, which is required for cAMP-mediated transcriptional activation of CREB. $PGE_2$ also activated the Ras/Raf/Erk pathway, and pretreatment with PD98059 abolished the protective effect of $PGE_2$. Furthermore, curcumin treatment greatly reduced phosphorylation of CREB, followed by a concomitant reduction of $NF-{\kappa}B$ (p50 and p65) subunit activation. $PGE_2$ markedly activated nuclear translocation of $NF-{\kappa}B$. EMSA confirmed the DNA-binding activities of $NF-{\kappa}B$ subunits. These results suggest that inhibition of curcumin-induced apoptosis by $PGE_2$ through activation of PKA, Ras, and $NF-{\kappa}B$ signaling pathways may provide a molecular basis for the reversal of curcumin-induced colon carcinoma cell death.
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