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UHPLC-ESI-qTOF-MS Analysis of Cyclopeptide Alkaloids in the Seeds of Ziziphus jujuba var. spinosa
Kang, Kyo Bin,Jang, Dae Sik,Kim, Jinwoong,Sung, Sang Hyun Korean Society for Mass Spectrometry 2016 Mass spectrometry letters Vol.7 No.2
An UHPLC-ESI-qTOF-MS analytical method was developed for cyclopeptide alkaloids in the seeds of Ziziphus jujuba var. spinosa (Semen Ziziphi Spinosae), which is a commonly used herb in Chinese and Korean traditional medicines. Considering the basicity of cyclopeptide alkaloids, a specific separation method was developed for an UHPLC system. The compounds were detected by DAD and ESI-qTOF-MS, and their fragmentation patterns were also acquired by MS<sup>E</sup> technologies. Peak-picking of major compounds was performed with nine previously isolated compounds and two reference standard compounds. Tandem MS fragmentation behaviors of type-Ia and -Ib cyclopeptide alkaloids were investigated with the acquired data to develop a strategy for dereplication of other cyclopeptide alkaloid compounds in Z. jujuba var. spinosa. Two more cyclopeptide alkaloids were tentatively identified with UHPLC-ESI-qTOF-MS using this method.
International Speech Coding Standards
Sung-Kyo Jung,Hong-Goo Kang 에스케이텔레콤 (주) 2003 Telecommunications Review Vol.13 No.5
Speech coding or speech compression is a field concerned with obtaining compact digital representations of voice signals for the purpose of efficient transmission or storage. This paper describes the basic concepts associated with speech coders and presents selected well-known algorithms. In addition, we present a summary of recent speech coding standards for narrowband and wideband telephony applications. Finally, we introduce current standards activities in 3GPP2 and ITU-T.
Catechin-Bound Ceanothane-Type Triterpenoid Derivatives from the Roots of <i>Zizyphus jujuba</i>
Kang, Kyo Bin,Kim, Hyun Woo,Kim, Jung Wha,Oh, Won Keun,Kim, Jinwoong,Sung, Sang Hyun American Society of Pharmacognosy 2017 Journal of natural products Vol.80 No.4
<P>Three unprecedented ceanothane-type triterpenoids, ent-epicatechinoceanothic acid A (1), ent-epicatechinoceanothic acid B (2), and epicatechino-3-deoxyceanothetric acid A (3), containing C-C bond linkages with catechin moieties, were isolated from the roots of Zizyphus jujuba. Their chemical structures, including absolute configurations, were established by spectroscopic analysis and calculation of their ECD spectra. A possible biogenetic pathway for C-C bond formation between the catechin and the triterpenoid moieties is presented. Compound 1 was evaluated for its antiproliferalive activity on HSC-T6 hepatic stellate cells.</P>
Chemical and genomic diversity of six <i>Lonicera</i> species occurring in Korea
Kang, Kyo Bin,Kang, Shin-Jae,Kim, Mi Song,Lee, Dong Young,Han, Sang Il,Kim, Tae Bum,Park, Jee Young,Kim, Jinwoong,Yang, Tae-Jin,Sung, Sang Hyun Elsevier 2018 Phytochemistry Vol.155 No.-
<P><B>Abstract</B></P> <P> <I>Lonicera</I> spp. (Caprifoliaceae) are important not only as a common medicinal herb in East Asia but also as one of the most problematic invasive species in North America. In the present study, we performed a systemic analysis of genomic and chemical diversity among six <I>Lonicera</I> species occurring in Korea, <I>L. japonica</I>, <I>L. maackii</I>, <I>L. insularis</I>, <I>L. sachalinensis</I>, <I>L. praeflorens</I>, and <I>L. vesicaria</I>, using chloroplast DNA whole genome shotgun (WGS) sequencing and LC–MS analyses. The phylogenetic and phylochemical relationships did not coincide with each other, but partial consistency could be found among them. InDel-based cDNA marker for authentication was developed based on the genome sequences. Flavonoids, iridoids, and organic acids were identified in the LC–MS analyses, and their inter-species distribution and localization were also revealed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Phylogeny between six <I>Lonicera</I> species was supposed based on chloroplast genome sequences. </LI> <LI> Specialized metabolites were profiled and compared by LC–MS. </LI> <LI> Partial consistency was found between genomic and chemical phylogeny. </LI> <LI> An Indel-based DNA barcode was developed for authentication of plants. </LI> <LI> Difference in chemotypes was suggested to be caused by ecological roles of iridoids. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Kang, Kyo Bin,Park, Eun Jin,Kim, Jinwoong,Sung, Sang Hyun American Society of Pharmacognosy 2017 Journal of natural products Vol.80 No.10
<P>Three compounds in a new class of 2-acetoxy-w-phenylpentaene fatty acid triglycosides, berchemiosides A-C (1-3), and a biosynthetically related phenolic glycoside (4) were isolated from the unripe fruits of Berchemia berchemiifolia, along with three flavonoid S-O-diglycosides (5-7) and three known flavonoids (8-10). Their chemical structures including absolute configurations were determined by spectroscopic analysis in combination with chemical derivatization. The pentaene group of 1 was found to have (6E,8E,10Z,12Z,14E)-geometry, whereas those of 2 and 3 exhibited all-E geometries. The isolated compounds were examined for their cytotoxicity and xanthine oxidase (XO) inhibitory activity; only compound 7 showed weak XO inhibitory activity.</P>