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chemical biology: a toolbox to unlock neurochemical epigenetics?

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Neural Regeneration Research 2021年第2期16卷 298-299页

作者： Dennis Ozcelik Center for Biopharmaceuticals Department of Drug Design and PharmacologyUniversity of CopenhagenCopenhagenDenmark Department of Chemistry and Biomolecular Sciences University of OttawaOttawaOntarioCanada

The complex challenges of studying neurochemistry: Neurochemistry comprises the molecular and biochemical roles of a vast variety of chemical compounds, including amino acids, peptides, gaseous molecules, and small mo... 详细信息

关键词： chemical chemistry gaseous

A rapid method for chemical fingerprint analysis of Panax notoginseng powders by ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry

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Chinese Journal of Natural Medicines 2015年第6期13卷 471-480页

作者： LIU Peng YU He-Shui ZHANG Li-Juan SONG Xin-Bo KANG Li-Ping LIU Jing-Yuan ZHANG Jie CAO Man YU Kate KANG Ting-Guo MA Bai-Ping Tianjin State Key Laboratory of Modern Chinese Medicine Tianjin University of Traditional Chinese Medicine Beijing Institute of Radiation Medicine College of Pharmacy Liaoning University of Traditional Chinese Medicine Waters Corporation Milford MA 01757 USA

A method coupling ultra-performance liquid chromatography(UPLC) with quadrupole time-of-flight mass spectrometer(Qtof MS) using the electrospray ionization(ESI) source was developed for the identification of the major saponins from Panax notoginseng powder(PNP). Ten different PNP samples were analyzed and evaluated for their quality by similarity evaluation and principle component analysis(PCA). Based on the accurate mass, summarized characteristic fragmentation behaviors, retention times of different types of saponins, related botanical biogenesis, and reported chromatographic behavior of saponins, fifty-one common peaks were effectively separated and identified, including 28 protopanaxadiol saponins and 18 protopanaxatriol saponins. Simultaneously, 15 significant discrepancy compounds were identified from the disqualified PNP samples. The established UPLC/Qtof MS fingerprint method was successfully applied for profiling and identifying the major saponins of PNP, providing a fast quality evaluation tool for distinguishing the authentic PNP and the adulterated products.

关键词： Panax notoginseng powder UPLC/Qtof MSE chemical fingerprint Ginsenosides Notoginsenosides

chemical synthesis and structure determination of venom toxins

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Chinese chemical Letters 2019年第7期30卷 1369-1373页

作者： Bobo Dang School of Life Sciences Westlake University Institute of Biology Westlake Institute for Advanced Study

Venom toxins are widely spread in nature, adopting diverse structures and functions. They often function by blocking or modulating important membrane protein targets thus can be promising therapeutic candidates and biophysical probes. In this review, we briefly discuss the total chemical synthesis of venom toxins including the different refolding strategies reported during the past decade as well as innovative approaches for structure determination.

关键词： Venom toxins chemical protein synthesis Structure determination Protein foldin Racemic protein crystallography

Comprehensive analysis of the chemical constituents in sulfur-fumigated Lonicerae Japonicae Flos using UHPLC-LTQ-Orbitrap mass spectrometry

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Chinese Journal of Natural Medicines 2020年第2期18卷 148-160页

作者： LIU Zi-Han WANG Yu-Qi MEI Xiao-Dan WANG Fei YANG Xian-Zhao LI Xiao-Dong JIANG Feng ZHANG Jia-Yu School of Chinese Pharmacy Beijing University of Chinese MedicineBeijing 102488China BUCM Institute of Liver Diseases Dongzhimen Hospital affiliated to Beijing University of Chinese MedicineBeijing 100700China Department of Hepatology Hubei Provincial Hospital of Traditional Chinese MedicineWuhan 430061China School of Pharmacy Binzhou Medical UniversityYantai 264003China

Lonicerae Japonicae Flos(LJF),a kind of traditional Chinese medicines(TCMs),has functions of detoxifying and evacuating heat.In the study,a method based on ultra-high performance liquid chromatography coupled with linear ion trap-Orbitrap mass spectrometry(UHPLC-LTQ-Orbitrap MS)was developed for the chemical constituent analysis of organic acids,flavonoids,iridoids and new-generated compounds in sulfur-fumigated LJF(SF-LJF).Based on the accurate mass measurement(<±5 ppm),chromatographic behavior and diagnostic product ions(DPIs),113 constituents were unambiguously or tentatively characterized from SFLJF extract,including 46 chlorogenic acids,19 flavonoids,29 iridoid glycosides and 19 newly-generated compounds(including 17 sulfur-containing derivatives).In addition,5-CQA(5-caffeoylquinic acid,chlorogenic acid)was chosen to be sulfur-fumigated for the result validation.It was found that the most significant change of LJF after sulfur fumigation was the occurrence of sulfate or sulfite esterification reactions,which resulted in the emergence of many new sulfur-containing components.Our results demonstrated that the established method was a useful and efficient analytical tool to comprehensively characterize the material basis of SF-LJF,and also an excellent guidance of quality control about LJF.

关键词： Sulfur fumigation Lonicerae Japonicae Flos chemical components analysis UHPLC-LTQ-Orbitrap MS

chemical composition and antioxidant activity of a Lebanese plant Euphorbia macroclada schyzoceras

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Asian Pacific Journal of Tropical Biomedicine 2013年第7期3卷 542-548页

作者： Hussein Farhan Hassan Rammal Akram Hijazi Ahmad Daher Mohamad Reda Hussein Annan Ali Chokr Ali Bassal Bassam Badran Doctoral School of Science and Technology Research Platform for Environmental Science Lebanese UniversityLebanon Faculty of Agricultural and Veterinary Sciences Lebanese UniversityLebanon Faculty of Sciences-1- Lebanese UniversityLebanon

Objective:To determine the chemical composition,total phenolic and total flavonoid contents ofthe crude extracts from leaves and stems of a Lebanese plantEuphorbia macroclada schyzoceras(E.macroclada),and to evaluate their antioxidant potential using DPPH,H2O2,and chelating offerrous ions tests.Methods:Quantification of the total phenolic and total flavonoid contents ofthe crude extracts from leaves and stems and the antioxidant activities were evaluated usingspectrophotometric analyses.The chemical composition has been estimated using differenttechniques such as IR,LC/MS and NMR.Results:Ethanolic extract from leaves ofE.macroclada was better than aqueous extract and showed higher content in total phenolic and total flavonoidthan found in the stems.On the other hand,using DPPH and H2O2tests,this extract from leavesshowed higher antioxidant capacity than aqueous extract.However,using the chelating of ferrousions test,the antioxidant activity of the aqueous extract of both stems and leaves was strongerthan that of ethanolic once.The chemical composition of the whole plant showed the presence ofsome aromatic compounds and fatty acids.Conclusions:Both ethanolic and water extracts fromboth parts of this plant are effective and have good antioxidant power.So,this plant can be usedin the prevention of a number of diseases related to oxidative stress.

关键词： Euphorbia macroclada schyzoceras Total phenolic Total flavonoid Antioxidant potential chemical composition

Decreasing incidence of cutaneous chemical burns in a resource limited burn centre: is this a positive effect of modernization?

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Burns & Trauma 2017年第1期5卷 64-67页

作者： R.E.E.Nnabuko C.P.Okoye I.S.Ogbonnaya Egi Isiwele Burns and Plastic Department National Orthopaedic HospitalPMB 01294 EnuguNigeria Department of Surgery University of Calabar Teaching HospitalCalabarNigeria

Background: Burns present a devastating injury to patients. Burns caused by chemical agents, present a worse scenario. In a resource limited country like Nigeria, readily available sources of these corrosive agents are mainly from lead-acid battery vendors and to some extent local small scale soap manufacturers who use caustic soda. We hypothesized that with the reduction in small scale soap manufacturing and increasing trend towards modernization in the use of dry cell batteries, chemical burns may be on the decline, and we sought to investigate this. Methods: The records of all acute burn patients seen at the Burns and Plastic Department of the National Orthopaedic Hospital Enugu Nigeria between January 2011 and December 2014 were retrospectively reviewed. The results were compared to similar studies carried out at the same centre. A questionnaire was administered to corrosive chemical (sulphuric and caustic soda) vendors to assess the trends in product sales and use in recent times. Results: A total of 624 acute burn cases were treated during the period;among which, 12 cases (1.9%) were chemical burns. When compared with previous studies at the centre, chemical burn cases were recorded as the lowest rate. The median age of patients was 24 years. There were eight males and four females. Interpersonal assault was the commonest mechanism of injury with sulphuric acid suspected to be the commonest agent in 83.3% of the cases, while 16.7% of the cases were from accidental use of caustic soda. The head and neck as well as the upper limbs were the most affected (30%). Twenty-six questionnaires to lead-acid vendors were analyzed and revealed that all respondents noticed a marked downward trend in the sale of either sulphuric acid or caustic soda, and they attributed this to the ready availability of imported alternatives to locally manufactured soap or wet lead-acid batteries. Ease of use, durability and convenience of the dry cell batteries were cited as principal reasons. Conclusion: There appears to be a downward t

关键词： chemical burns Interpersonal assault Lead-acid battery vendors Resource-limited country Modernization

chemical Kinetic Modeling for the Effects of Methyl Ester Moiety in Biodiesel on PAHs and NO_x Formation

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Transactions of Tianjin University 2013年第3期19卷 168-173页

作者：舒歌群徐彪张韦赵伟卫海桥朱天宇 State Key Laboratory of Engines Tianjin University School of Civil Engineering Kunming University of Science and Technology

In order to investigate the effects of methyl ester moiety on polycyclic aromatic hydrocarbons (PAHs) and NO x formation in biodiesel combustion, the combined models were developed based on detailed methyl butanoate (MB) oxidation model and n-butane model. Also, PAHs detailed reaction mechanism and NO x formation mechanism were added to the detailed models to form the combined models. The combined models were used to compare the combustion of n-butane and MB in a shock tube simulation to understand the effects of methyl ester moiety. The results indicated that compared with n-butane, the methyl ester moiety in MB leads to different reaction pathways, more CO and CO 2 formation and less formation of PAHs precursors such as ethylene and acetylene. In addition, a better chemical insight into the effects of methyl ester moiety on NO x formation was given, which will help to understand the combustion process of biodiesel.

关键词： biodiesel methyl butanoate PAHs NOx chemical kinetics

chemical synthesis and racemic crystallization of rat C5a-desArg

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Chinese chemical Letters 2020年第3期31卷 693-696页

作者： Chao Zuo Baochang Zhang Meng Wu Donald Bierer Jing Shi Ge-Min Fang School of Life Science Institutes of Physical Science and InformationTechnologyAnhui UniversityHefei 230601China Department of Chemistry Tsinghua UniversityBeijing 100084China Department of Chemistry University of Science and Technology of ChinaHefei 230601China Bayer AG Department of Medicinal ChemistryAprather Weg 18A42096WuppertalGermany

The deletion of the C-terminal arginine of the anaphylatoxin protein C5a reduces it receptor binding affinity.Understanding how C-terminal arginine affects the structure and bioactivity of C5a is important for the development of C5a C-terminal mimics as drug candidates.Herein,we report the total chemical synthesis of rat C5a and its D-enantiomer with its C-terminal arginine deleted,namely L-rC5a-desArg and D-rC5a-desArg.The structure of rC5a-desArg was then determined by racemic crystallography for the first time.The C-terminal residues of rC5a-Arg were found to expand from the fourth helix in a continuous helical confo rmation.This C-terminal conformation is significantly different from that of the previously reported full-length of C5a,indicating that the deletion of C-terminal arginine residue could result in the destruction of a positively charged surface formed by two adjacent Arg residues in C5a.

关键词： Anaphylatoxin C5a Racemic crystallization Solid phase peptide synthesis chemical protein synthesis Hydrazide-based native chemical ligation

chemical SPECIES OF IRIDIUM AND OTHER TRACE ELEMENTS AT K-T BOUNDARY CLAY LAYER, STEVNS KLINT, DENMARK, AND ITS IMPLICATION

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Science China Chemistry 1991年第12期34卷 1492-1500页

作者：柴之芳孔屏毛雪瑛马淑兰周瑶琪马建国 Institute of High Energy Physics Academia Sinica P.O. Box 2732 Beijing 100080 PRC

The chemical species of anomalous Ir in the Fish Clay K-T boundary at Stevns Klint, Denmark, was studied by using a newly-developed chemical stepwise dissolution procedure and neutron activation analysis. The experimental results indicate that the anomalous Ir mostly exists in the acid-insoluble residue phase. The Ir pattern of the K-T boundary resembles that of the Ningqiang carbonaceous chondrite, while remarkably different from those of the ultrabasic rock and volcanic lava. Thus, we deduce that the Ir anomaly at K-T boundary is mainly extraterrestrial, instead of volcanogenic or geochemical enrichment origin. The patterns of other trace elements in various phases also confirm the above conclusion.

关键词： K-T boundary Ir anomaly chemical species event stratigraphy.