A New Cytotoxic Phenylbutenoid Dimer from the Rhizomes of Zingiber cassumunar

Han, Ah-Reum et al 이화여자대학교 2004 藥學硏究論文集 Vol.- No.14

A new phenylbutenoid dimer, (±)-trans-3-(4-hydroxy-3-meth-oxyphenyl)4-[(E)-3,4-dimethoxystyryl]cyclohex-1-ene, was isolated from the rhizomes of Zingiber cassumunar along with the three known compounds, (±)-trans-3-)3,4-dimethoxyphenyl)-4-[(E)-3,4-dimethoxystyryl]cyclohex-1-ene, 4-(3,4-dimethoxyphenyl)but-1,3-diene, and 4-(2,4,5-trimethoxyphenyl)but-1,3-diene by bioassay-directed fractionation using the A549 human cancer cell line cytotoxicity assay. Structure of the new compound was elucidated by spectral analysis, including 1D and 2D NMR experiments.

Cytotoxic Constituents of the Octocoral Dendronephthya gigantea

Han Ah Reum,Song Jun Im,Jang Dae Sik,Min Hye Young,Lee Sang Kook,Seo Eun Kyoung The Pharmaceutical Society of Korea 2005 Archives of Pharmacal Research Vol.28 No.3

A known monoalkyl glycerol ether, ($\pm$)-1-nonadecyloxy-2,3-propanediol (1) was isolated from the ethyl acetate extract of a soft coral Dendronephthya gigantea as a weakly cytotoxic constituent against four human cancer cell lines, A549, HT-29, HT-1080, and SNU-638. In addition, a known ceramide, (28,3R,4E,8E)-N-hexadecanoyl-2-amino-4,8-octadecadiene-1 ,3-diol (2), was also isolated as an inactive constituent. This is the first report on the isolation of the compounds 1 and 2 from the octocoral, Dendronephthya species.

A New Flavanone Glycoside from the Dried Immature Fruits of Poncirus trifoliate

( Ah Reum Han ),( Jong Bin Kim ),( Jun Lee ),( Joo Won Mam ),( Ik Soo Lee ),( Chang Koo Shim ),( Kyung Tae Lee ),( Eun Kyoung Seo ) 전남대학교 약품개발연구소 2007 약품개발연구지 Vol.16 No.-

Glycogen Metabolism in Vibrio vulnificus Affected by malP and malQ

Han, Ah-Reum,Lee, Yeon-Ju,Wang, Tianshi,Kim, Jung-Wan The Korean Society for Microbiology and Biotechnol 2018 한국미생물·생명공학회지 Vol.46 No.1

Vibrio vulnificus needs various responsive mechanisms to survive and transmit successfully in alternative niches of human and marine environments, and to ensure the acquisition of steady energy supply to facilitate such unique life style. The bacterium had genetic constitution very different from that of Escherichia coli regarding metabolism of glycogen, a major energy reserve. V. vulnificus accumulated more glycogen than other bacteria and at various levels according to culture medium and carbon source supplied in excess. Glycogen was accumulated to the highest level in Luria-Bertani (3.08 mg/mg protein) and heart infusion (4.30 mg/mg protein) complex media supplemented with 1% (w/v) maltodextrin at 3 h into the stationary phase. Regarding effect of carbon source, more glycogen was accumulated when maltodextrin (2.34 mg/mg protein) was added than when glucose or maltose (0.78.1-14 mg/mg protein) was added as an excessive carbon source to M9 minimal medium, suggesting that maltodextrin metabolism might affect glycogen metabolism very closely. These results were supported by the analysis using the malP (encoding a maltodextrin phosphorylase) and malQ (encoding a 4-${\alpha}$-glucanotransferase) mutants, which accumulated much less glycogen than wild type when either glucose or maltodextrin was supplied as an excessive carbon source, but at different levels (3.1-80.3% of wild type glycogen). Therefore, multiple pathways for glycogen metabolism were likely to function in V. vulnificus and that responding to maltodextrin might be more efficient in synthesizing glycogen. All of the glycogen samples from 3 V. vulnificus strains under various conditions showed a narrow side chain length distribution with short chains (G4-G6) as major ones. Not only the comparatively large accumulation volume but also the structure of glycogen in V. vulnificus, compared to other bacteria, may explain durability of the bacterium in external environment.

Quantification of Antioxidant Phenolic Compounds in a New Chrysanthemum Cultivar by High-Performance Liquid Chromatography with Diode Array Detection and Electrospray Ionization Mass Spectrometry

Han, Ah-Reum,Kim, Hyo Young,So, Yangkang,Nam, Bomi,Lee, Ik-Soo,Nam, Joo-Won,Jo, Yeong Deuk,Kim, Sang Hoon,Kim, Jin-Baek,Kang, Si-Yong,Jin, Chang Hyun Hindawi 2017 International journal of analytical chemistry Vol.2017 No.-

<P>The flowers of<I> Chrysanthemum morifolium</I> Ramat. have been used as an herbal tea and in traditional medicine, and the plant has been developed to produce horticultural cultivars of various colors and shapes. In this study, a new chrysanthemum cultivar with dark purple petals (<I>C. morifolium</I> cv. ARTI-Dark Chocolate; ADC) was developed by radiation-induced mutation breeding of its original cultivar with purple striped white petals (<I>C. morifolium</I> cv. Noble Wine, NW). The phenolic profile and antioxidant property of ADC were investigated and compared with NW and the commercially available medicinal herb,<I> C. morifolium</I> with yellow petals (CM), in order to find a scientific support to produce a new source of natural antioxidant. Flavonoid and phenolic acid profiles of the ethanol extracts of the three flowers were analyzed by high-performance liquid chromatography-diode array detector-electrospray ionization mass spectrometry (HPLC-DAD-ESIMS), while antioxidant properties were evaluated using the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging assay. Among the tested flowers, ADC possessed the strongest antioxidant capacity and the highest phenolic contents. Flavonoids (acacetin, apigenin, luteolin, acacetin-7-<I>O</I>-<I>β</I>-glucoside, apigenin-7-<I>O</I>-<I>β</I>-glucoside, luteolin-7-<I>O</I>-<I>β</I>-glucoside, and linarin) and phenolic acids (chlorogenic acid and mixture of 1,4-, 1,5-, and 3,5-dicaffeoylquinic acids) were identified and quantified.</P>

Characterization of a cold-adapted debranching enzyme and its role in glycogen metabolism and virulence of Vibrio vulnificus MO6-24/O

Han Ah-Reum,Kim Haeyoung,Park Jong-Tae,Kim Jung-Wan 한국미생물학회 2022 The journal of microbiology Vol.60 No.4

Vibrio vulnificus MO6-24/O has three genes annotated as debranching enzymes or pullulanase genes. Among them, the gene encoded by VVMO6_03032 (vvde1) shares a higher similarity at the amino acid sequence level to the glycogen debranching enzymes, AmyX of Bacillus subtilis (40.5%) and GlgX of Escherichia coli (55.5%), than those encoded by the other two genes. The vvde1 gene encoded a protein with a molecular mass of 75.56 kDa and purified Vvde1 efficiently hydrolyzed glycogen and pullulan to shorter chains of maltodextrin and maltotriose (G3), respectively. However, it hydrolyzed amylopectin and soluble starch far less efficiently, and β-cyclodextrin (β-CD) only rarely. The optimal pH and temperature of Vvde1 was 6.5 and 25°C, respectively. Vvde1 was a cold-adapted debranching enzyme with more than 60% residual activity at 5°C. It could maintain stability for 2 days at 25°C and 1 day at 35°C, but it destabilized drastically at 40°C. The Vvde1 activity was inhibited considerably by Cu2+, Hg2+, and Zn2+, while it was slightly enhanced by Co2+, Ca2+, Ni2+, and Fe2+. The vvde1 knock-out mutant accumulated more glycogen than the wild-type in media supplemented with 1.0% maltodextrin; however, the side chain length distribution of glycogen was similar to that of the wild-type except G3, which was much more abundant in the mutant. Therefore, Vvde1 seemed to debranch glycogen with the degree of polymerization 3 (DP3) as the specific target branch length. Virulence of the pathogen against Caenorhabditis elegans was attenuated significantly by the vvde1 mutation. These results suggest that Vvde1 might be a unique glycogen debranching enzyme that is involved in both glycogen utilization and shaping of glycogen molecules, and contributes toward virulence of the pathogen.

Relationship between vertical components of maxillary molar and craniofacial frame in normal occlusion: Cephalometric calibration on the vertical axis of coordinates

Han, Ah-Reum,Kim, Jongtae,Yang, Il-Hyung The Korean Association Of Orthodontists 2021 대한치과교정학회지 Vol.51 No.1

Objective: The aim of this study was to evaluate the correlation between the vertical position of maxillary first molar and vertical skeletal measurements in lateral cephalograms by using new linear measurements on the vertical axis of coordinates with calibration. Methods: The vertical position of maxillary first molar (U6-SN), and the conventionally used variables (ConV) and the newly derived linear variables (NwLin) for vertical skeletal patterns were measured in the lateral cephalograms of 103 Korean adults with normal occlusions. Pearson correlation analyses and multiple linear regression analyses were performed with and without calibration using the anterior and posterior cranial base (ACB and PCB, respectively) lengths to identify variables related to U6-SN. Results: The PCB-calibrated statistics showed the best power of explanation. ConV indicating skeletal hyperdivergency was significantly correlated with U6-SN. Six NwLin regarding the position of palatal plane were positively correlated with U6-SN. Each multiple linear regression analysis generated a two-variable model: sella and nasion to palatal plane. Among the three models, the PCB-calibrated model yielded highest adjusted R2 value, 0.880. Conclusions: U6-SN could be determined by the vertical position of the maxilla, which could then be used to plan the amount of molar intrusion and estimate its clinical stability. Cephalometric calibration on the vertical axis of coordinates by using PCB for vertical linear measurements could strengthen the analysis itself.

Glycogen Metabolism in Vibrio vulnificus Affected by malP and malQ

( Ah-reum Han ),( Yeon-ju Lee ),( Tianshi Wang ),( Jung-wan Kim ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 한국미생물·생명공학회지 Vol.46 No.1

Vibrio vulnificus needs various responsive mechanisms to survive and transmit successfully in alternative niches of human and marine environments, and to ensure the acquisition of steady energy supply to facilitate such unique life style. The bacterium had genetic constitution very different from that of Escherichia coli regarding metabolism of glycogen, a major energy reserve. V. vulnificus accumulated more glycogen than other bacteria and at various levels according to culture medium and carbon source supplied in excess. Glycogen was accumulated to the highest level in Luria-Bertani (3.08 mg/mg protein) and heart infusion (4.30 mg/mg protein) complex media supplemented with 1% (w/v) maltodextrin at 3 h into the stationary phase. Regarding effect of carbon source, more glycogen was accumulated when maltodextrin (2.34 mg/mg protein) was added than when glucose or maltose (0.78-1.14 mg/mg protein) was added as an excessive carbon source to M9 minimal medium, suggesting that maltodextrin metabolism might affect glycogen metabolism very closely. These results were supported by the analysis using the malP (encoding a maltodextrin phosphorylase) and malQ (encoding a 4-α-glucanotransferase) mutants, which accumulated much less glycogen than wild type when either glucose or maltodextrin was supplied as an excessive carbon source, but at different levels (3.1-80.3% of wild type glycogen). Therefore, multiple pathways for glycogen metabolism were likely to function in V. vulnificus and that responding to maltodextrin might be more efficient in synthesizing glycogen. All of the glycogen samples from 3 V. vulnificus strains under various conditions showed a narrow side chain length distribution with short chains (G4-G6) as major ones. Not only the comparatively large accumulation volume but also the structure of glycogen in V. vulnificus, compared to other bacteria, may explain durability of the bacterium in external environment.

A New Flavanone Glycoside from the Dried Immature Fruits of <i>Poncirus trifoliata</i>

Han, Ah-Reum,Kim, Jong-Bin,Lee, Jun,Nam, Joo-Won,Lee, Ik-Soo,Shim, Chang-Koo,Lee, Kyung-Tae,Seo, Eun-Kyoung Pharmaceutical Society of Japan 2007 Chemical & pharmaceutical bulletin Vol.55 No.8

<P>A new flavanone glycoside, (2<I>R</I>)-5-hydroxy-4′-methoxyflavanone-7-<I>O</I>-{β-glucopyranosyl-(1→2)-β-glucopyranoside} (1), was isolated from the EtOAc extract of dried immature fruit of <I>Poncirus trifoliata</I>, together with three known compounds, (2<I>S</I>)-poncirin (2), (2<I>S</I>)-naringin (3), and (2<I>S</I>)-poncirenin (4). The structure of compound 1 was elucidated by spectroscopic data analysis, including 1D and 2D NMR experiments. Among the isolates, compound 2 exhibited considerable inhibitory activity against lipopolysaccharide (LPS)-induced prostaglandin E<SUB>2</SUB> (PGE<SUB>2</SUB>) and interleukin-6 (IL-6) production, and mRNA expression in RAW 264.7 murine macrophage cells.</P>

Essential Role of the Linker Region in the Higher Catalytic Efficiency of a Bifunctional MsrA–MsrB Fusion Protein

Han, Ah-reum,Kim, Moon-Jung,Kwak, Geun-Hee,Son, Jonghyeon,Hwang, Kwang Yeon,Kim, Hwa-Young American Chemical Society 2016 Biochemistry Vol.55 No.36

<P>Many bacteria, particularly pathogens, possess methionine sulfoxide reductase A (MsrA) and B (MsrB) as a fusion form (MsrAB). However, it is not clear why they possess a fusion MsrAB form rather than the separate,enzymes that exist in most organisms. In this study, we performed biochemical and kinetic analyses of MsrAB from Treponema denticola (TdMsrAB), single-domain forms (TdMsrA and TdMsrB), and catalytic Cys mutants (TdMsrAB(C11S) and TdMsrAB(C285S)) We found that the catalytic efficiency of both MsrA and MsrB increased after fusion of the domains and that the linker region (iloop) that connects TdMsrA and TdMsrB is required for the higher catalytic efficiency of TdMsrAB. We also determined the crystal structure of TdMsrAB at 2.3 angstrom, showing that the iloop mainly interacts with TdMsrB via hydrogen bonds. Further kinetic analysis using the iloop mutants revealed that the iloop-TdMsrB interactions are critical to MsrB and MsrA activities. We also report the structure in which an oxidized form of dithiothreitol, an in vitro reductant for MsrA and MsrB, is present in the active site of TdMsrA. Collectively, the results of this study reveal an essential role of the iloop in maintaining the higher catalytic efficiency of the MsrAB fusion enzyme and provide a better understanding of why the MsrAB enzyme exists as a fused form.</P>