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A New 5α,8α-Epidioxy Sterol from a Marine Sponge Psammocinia Species
Hye Jin Park1,,Xuan Luo1,,Jongki Hong2,,Dong-kyoo Kim3,,Kwang Sik Im1, and,Jee H. Jung1* 한국생약학회 2005 Natural Product Sciences Vol.11 No.4
An investigation of the MeOH soluble fractions of a marine sponge Psammocinia sp. (Order:Dictyoceratida) led to the isolation of a new epidioxy sterol (1) and four known sterols (2-5). Their planarstructures were defined by analyses of the spectroscopic data. The 27-nor-24-methylcholestan type side chain withan epidioxy nucleus (1) was unprecedented. Compounds 1-5 were isolated from a sponge Psammocinia sp. for the first time.
General Fragmentations of Alkaloids in Electrospray Ionization Tandem Mass Spectrometry
( Hee Jung Shim ),( Ji Ye Lee ),( Byungjoo Kim ),( Jongki Hong ) 한국질량분석학회 2013 Mass spectrometry letters Vol.4 No.4
Various types of alkaloids observed in several herbal medicines were analyzed by electrospray ionization tandem mass spectrometry in positive ion mode. In the present study, MS/MS spectralpatterns were investigated for eight-types of alkaloids (aporpine, protoberberine, tetrahydroprotoberberine, benzylisoquinoline, protopine, phthalide, morpine, and bisbenzylisoquinoline). For aporpine- and protoberberine-type alkaloids, main fragmentations occurred at substituted groups on rigid ring structures, not showing ring fusion. Interesting fragmentations due to iminolization and retro-Diels-Alder (RDA) reaction were observed in MS/MS spectra of protopine- and tetrahydroprotobereberine-type alkaloids. Also, several types of fragmentations such as inductive cleavage and α-cleavage, or bond cleavage between two ring structures were observed depending on their structural characteristics. These fragmentation patterns are expected to allow instant classification of the specific alkaloid type in various MS/MS spectra of alkaloids.
Sim, Hee-Jung,Lee, Seul gi,Park, Na-Hyun,Kim, Youna,Cho, Hyun-Woo,Hong, Jongki The Korean Society of Analytical Science 2017 분석과학 Vol.30 No.2
Here we reported a methodology for identification of triacylglycerols (TAGs) and diacylglycerols (DAGs) in coix seed by preparative thin layer chromatography (prep-TLC) and non-aqueous reversed-phase liquid chromatography (NARP LC)-atmospheric pressure chemical ionization (APCI) tandem mass spectrometry (MS/MS). Lipid components were extracted from coix seed by reflux extraction using n-hexane for 3 hr. TAGs and DAGs in coix seed extract were effectively purified and isolated from matrix interferences by prep-TLC and then analyzed by LC-APCI-MS and MS/MS for identification. TAGs were effectively identified taking into consideration of their LC retention behavior, APCI-MS spectra patterns, and MS/MS spectra of $[DAG]^+$ ions. In MS/MS spectra of TAGs, diacylglycerol-like fragment $[DAG]^+$ ions were useful to identify TAGs with isobaric fragment ions. Based on an established method, 27 TAGs and 8 DAGs were identified in coix seed extract. Among them, 15 TAGs and 8 DAGs were for the first time observed in coix seed. Interestingly, some of TAGs isolated by prep-TLC were partly converted into DAGs through probably photolysis process during storing in room temperature. Thus, degradation phenomenon of TAGs should be considered in the quality evaluation and nutritional property of coix seed. LC-APCI-MS/MS combined with prep-TLC will be practical method for precise TAG and DAG analysis of other herbal plants.