18β-glycyrrhetinic acid inhibits proliferation of gastric cancer cells through regulating the miR-345-5p/TGM2 signaling pathway

BACKGROUND Gastric cancer(GC)is a common gastrointestinal malignancy worldwide.Based on cancer-related mortality,the current prevention and treatment strategies for GC still show poor clinical results.Therefore,it is important to find effective drug treatment targets.AIM To explore the molecular mechanism of 18β-glycyrrhetinic acid(18β-GRA)regulating the miR-345-5p/TGM2 signaling pathway to inhibit the proliferation of GC cells.METHODS CCK-8 assay was used to determine the effect of 18β-GRA on the survival rate of GES-1 cells and AGS and HGC-27 cells.Cell cycle and apoptosis were detected by flow cytometry,cell migration was detected by a wound healing assay,the effect of 18β-GRA on subcutaneous tumor growth in BALB/c nude mice was investigated,and the cell autophagy level was determined by MDC staining.TMT proteomic analysis was used to detect the differentially expressed autophagy-related proteins in GC cells after 18β-GRA intervention,and then the protein-protein interaction was predicted using STRING(https://string-db.org/).MicroRNAs(miRNAs)transcriptome analysis was used to detect the miRNA differential expression profile,and use miRBase(https://www.mirbase/)and TargetScan(https://www.targetscan.org/)to predict the miRNA and complementary binding sites.Quantitative real-time polymerase chain reaction was used to detect the expression level of miRNA in 18β-GRA treated cells,and western blot was used to detect the expression of autophagy related proteins.Finally,the effect of miR-345-5p on GC cells was verified by mir-345-5p overexpression.RESULTS 18β-GRA could inhibit GC cells viability,promote cell apoptosis,block cell cycle,reduce cell wound healing ability,and inhibit the GC cells growth in vivo.MDC staining results showed that 18β-GRA could promote autophagy in GC cells.By TMT proteomic analysis and miRNAs transcriptome analysis,it was concluded that 18β-GRA could down-regulate TGM2 expression and up-regulate miR-345-5p expression in GC cells.Subsequently,we verified that TGM2 is the target of miR-345-5p,and that overexpression of miR-345-5p significantly inhibited the protein expression level of TGM2.Western blot showed that the expression of autophagy-related proteins of TGM2 and p62 was significantly reduced,and LC3II,ULK1 and AMPK expression was significantly increased in GC cells treated with 18β-GRA.Overexpression of miR-345-5p not only inhibited the expression of TGM2,but also inhibited the proliferation of GC cells by promoting cell apoptosis and arresting cell cycle.CONCLUSION 18β-GRA inhibits the proliferation of GC cells and promotes autophagy by regulating the miR-345-5p/TGM2 signaling pathway.

Novel 18β-glycyrrhetinic acid amide derivatives show dual-acting capabilities for controlling plant bacterial diseases through ROS-mediated antibacterial efficiency and activating plant defense responses

Natural products have long been a crucial source of,or provided inspiration for new agrochemical discovery.Naturally occurring 18β-glycyrrhetinic acid shows broad-spectrum bioactivities and is a potential skeleton for novel drug discovery.To extend the utility of 18β-glycyrrhetinic acid for agricultural uses,a series of novel 18β-glycyrrhetinic acid amide derivatives were prepared and evaluated for their antibacterial potency.Notably,compound 5k showed good antibacterial activity in vitro against Xanthomonas oryzae pv.oryzae(Xoo,EC50=3.64 mg L–1),and excellent protective activity(54.68%)against Xoo in vivo.Compound 5k induced excessive production and accumulation of reactive oxygen species in the tested pathogens,resulting in damaging the bacterial cell envelope.More interestingly,compound 5k could increase the activities of plant defense enzymes including catalase,superoxide dismutase,peroxidase,and phenylalanine ammonia lyase.Taken together,these enjoyable results suggested that designed compounds derived from 18β-glycyrrhetinic acid showed potential for controlling intractable plant bacterial diseases by disturbing the balance of the phytopathogen’s redox system and activating the plant defense system.

18β-glycyrrhetinic acid promotes gastric cancer cell autophagy and inhibits proliferation by regulating miR-328-3p/signal transducer and activator of transcription 3

BACKGROUND Gastric cancer(GC)is one of the most common cancer types worldwide,and its prevention and treatment methods have garnered much attention.As the active ingredient of licorice,18β-glycyrrhetinic acid(18β-GRA)has a variety of pharmacological effects.The aim of this study was to explore the effective target of 18β-GRA in the treatment of GC,in order to provide effective ideas for the clinical prevention and treatment of GC.AIM To investigate the mechanism of 18β-GRA in inhibiting cell proliferation and promoting autophagy flux in GC cells.METHODS Whole transcriptomic analyses were used to analyze and screen differentially expressed microRNAs(miRNAs)in GC cells after 18β-GRA intervention.Lentivirus-transfected GC cells and the Cell Counting Kit-8 were used to detect cell proliferation ability,cell colony formation ability was detected by the clone formation assay,and flow cytometry was used to detect the cell cycle and apoptosis.A nude mouse transplantation tumor model of GC cells was constructed to verify the effect of miR-328-3p overexpression on the tumorigenicity of GC cells.Tumor tissue morphology was observed by hematoxylin and eosin staining,and microtubule-associated protein light chain 3(LC3)expression was detected by immunohistochemistry.TransmiR,STRING,and miRWalk databases were used to predict the relationship between miR-328-3p and signal transducer and activator of transcription 3(STAT3)-related information.Expression of STAT3 mRNA and miR-328-3p was detected by quantitative polymerase chain reaction(qPCR)and the expression levels of STAT3,phosphorylated STAT3(p-STAT3),and LC3 were detected by western blot analysis.The targeted relationship between miR-328-3p and STAT3 was detected using the dual-luciferase reporter gene system.AGS cells were infected with monomeric red fluorescent protein-green fluorescent protein-LC3 adenovirus double label.LC3 was labeled and autophagy flow was observed under a confocal laser microscope.RESULTS The expression of miR-328-3p was significantly upregulated after 18β-GRA intervention in AGS cells(P=4.51E-06).Overexpression of miR-328-3p inhibited GC cell proliferation and colony formation ability,arrested the cell cycle in the G0/G1 phase,promoted cell apoptosis,and inhibited the growth of subcutaneous tumors in BALB/c nude mice(P<0.01).No obvious necrosis was observed in the tumor tissue in the negative control group(no drug intervention or lentivirus transfection)and vector group(the blank vector for lentivirus transfection),and more cells were loose and necrotic in the miR-328-3p group.Bioinformatics tools predicted that miR-328-3p has a targeting relationship with STAT3,and STAT3 was closely related to autophagy markers such as p62.After overexpressing miR-328-3p,the expression level of STAT3 mRNA was significantly decreased(P<0.01)and p-STAT3 was downregulated(P<0.05).The dual-luciferase reporter gene assay showed that the luciferase activity of miR-328-3p and STAT33’untranslated regions of the wild-type reporter vector group was significantly decreased(P<0.001).Overexpressed miR-328-3p combined with bafilomycin A1(Baf A1)was used to detect the expression of LC3 II.Compared with the vector group,the expression level of LC3 II in the overexpressed miR-328-3p group was downregulated(P<0.05),and compared with the Baf A1 group,the expression level of LC3 II in the overexpressed miR-328-3p+Baf A1 group was upregulated(P<0.01).The expression of LC3 II was detected after intervention of 18β-GRA in GC cells,and the results were consistent with the results of miR-328-3p overexpression(P<0.05).Additional studies showed that 18β-GRA promoted autophagy flow by promoting autophagosome synthesis(P<0.001).qPCR showed that the expression of STAT3 mRNA was downregulated after drug intervention(P<0.05).Western blot analysis showed that the expression levels of STAT3 and p-STAT3 were significantly downregulated after drug intervention(P<0.05).CONCLUSION 18β-GRA promotes the synthesis of autophagosomes and inhibits GC cell proliferation by regulating the miR-328-3p/STAT3 signaling pathway.

Effect of glycyrrhizic acid and 18β-glycyrrhetinic acid on the differentiation of human umbilical cord-mesenchymal stem cells into hepatocytes

BACKGROUND End-stage liver disease is a global health complication with high prevalence and limited treatment options.Cell-based therapies using mesenchymal stem cells(MSCs)emerged as an alternative approach to support hepatic regeneration.In vitro preconditioning strategies have been employed to strengthen the regenerative and differentiation potential of MSCs towards hepatic lineage.Chemical compounds of the triterpene class;glycyrrhizic acid(GA)and 18β-glycyrrhetinic acid(GT)possess diverse therapeutic properties including hepatoprotection and anti-fibrosis characteristics.They are capable of modulating several signaling pathways that are crucial in hepatic regeneration.Preconditioning with hepato-protective triterpenes may stimulate MSC fate transition towards hepatocytes.AIM To explore the effect of GA and GT on hepatic differentiation of human umbilical cord-MSCs(hUC-MSCs).METHODS hUC-MSCs were isolated and characterized phenotypically by flow cytometry and immunocytochemistry for the expression of MSC-associated surface molecules.Isolated cells were treated with GA,GT,and their combination for 24 h and then analyzed at three time points;day 7,14,and 21.qRT-PCR was performed for the expression of hepatic genes.Expression of hepatic proteins was analyzed by immunocytochemistry at day 21.Periodic acid Schiff staining was performed to determine the functional ability of treated cells.RESULTS The fusiform-shaped morphology of MSCs in the treatment groups in comparison with the untreated control,eventually progressed towards the polygonal morphology of hepatocytes with the passage of time.The temporal transcriptional profile of preconditioned MSCs displayed significant expression of hepatic genes with increasing time of differentiation.Preconditioned cells showed positive expression of hepatocyte-specific proteins.The results were further corroborated by positive periodic acid Schiff staining,indicating the presence of glycogen in their cytoplasm.Moreover,bi-nucleated cells,which is the typical feature of hepatocytes,were also seen in the preconditioned cells.CONCLUSION Preconditioning with glycyrrhizic acid,18β-glycyrrhetinic acid and their combination,successfully differentiates hUC-MSCs into hepatic-like cells.These MSCs may serve as a better therapeutic option for degenerative liver diseases in future.

Advances in Research on Anti-cancer Mechanism of 18β Glycyrrhetinic Acid

Glycyrrhiza uralensis Fisch has been used to treat the symptoms of organ fever, food poisoning, typhoid fever, sore throat, cough due to lung heat, children's diseases and so on since the ancient times. It is a solid Chinese herbal medicine which is good for the health. In recent years, it has been found that licorice extract also has excellent anti-cancer effect. The 18β glycyrrhetinic acid, obtained by hydrolysis of precursor glycyrrhizic acid, is a relatively efficient anti-cancer ingredient. 18β glycyrrhetinic acid can exert anti-cancer effects by inhibiting cancer cell proliferation, inducing apoptosis of cancer cells, inhibiting invasion and metastasis of cancer cells, preventing oxidation, inhibiting neovascularization, inhibiting lymphangiogenesis, and regulating hormone secretion. This paper reviewed the advances in research of the anticancer mechanism of 18β glycyrrhetinic acid, to provide a theoretical basis for future research.

18β-glycyrrhetinic acid regulates mitochondrial ribosomal protein L35-associated apoptosis signaling pathways to inhibit proliferation of gastric carcinoma cells

BACKGROUND Gastric carcinoma(GC)is a common gastrointestinal malignancy worldwide.Based on the cancer-related mortality,the current prevention and treatment strategies for GC still show poor clinical results.Therefore,it is important to find effective drug treatment targets.AIM To explore the mechanism by which 18β-glycyrrhetinic acid(18β-GRA)regulates mitochondrial ribosomal protein L35(MRPL35)related signal proteins to inhibit the proliferation of GC cells.METHODS Cell counting kit-8 assay was used to detect the effects of 18β-GRA on the survival rate of human normal gastric mucosal cell line GES-1 and the proliferation of GC cell lines MGC80-3 and BGC-823.The apoptosis and cell cycle were assessed by flow cytometry.Cell invasion and migration were evaluated by Transwell assay,and cell scratch test was used to detect cell migration.Furthermore,a tumor model was established by hypodermic injection of 2.5×106 BGC-823 cells at the selected positions of BALB/c nude mice to determine the effect of 18β-GRA on GC cell proliferation,and quantitative reverse transcription-polymerase chain reaction(qRT-PCR)was used to detect MRPL35 expression in the engrafted tumors in mice.We used the term tandem mass tag(TMT)labeling combined with liquid chromatography–tandem mass spectrometry to screen for differentially expressed proteins(DEPs)extracted from GC cells and control cells after 18β-GRA intervention.A detailed bioinformatics analysis of these DEPs was performed,including Gene Ontology annotation and enrichment analysis,Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis,and so on.Moreover,STRING database(https://string-db.org/)was used to predict proteinprotein interaction(PPI)relationships and Western blot was used to detect the expression of proteins of interest in GC cells.RESULTS The results indicated that 18β-GRA could inhibit the proliferation of GC cells in a dose-and timedependent manner.It could induce GC cell apoptosis and arrest the cell cycle at G0/G1 phase.The proportion of cells arrested at S phase decreased with the increase of 18-GRA dose,and the migration and invasiveness of GC cells were inhibited.The results of animal experiments showed that 18β-GRA could inhibit tumor formation in BALB/c nude mice,and qRT-PCR results showed that MRPL35 expression level was significantly reduced in the engrafted tumors in mice.Using TMT technology,609 DEPs,among which 335 were up-regulated and 274 were down-regulated,were identified in 18β-GRA intervention compared with control.We found that the intervention of 18β-GRA in GC cells involved many important biological processes and signaling pathways,such as cellular processes,biological regulation,and TP53 signaling pathway.Notably,after the drug intervention,MRPL35 expression was significantly down-regulated(P=0.000247),TP53 expression was up-regulated(P=0.02676),and BCL2L1 was down-regulated(P=0.01699).Combined with the Retrieval of Interacting Genes/Proteins database,we analyzed the relationship between MRPL35,TP53,and BCL2L1 signaling proteins,and we found that COPS5,BAX,and BAD proteins can form a PPI network with MRPL35,TP53,and BCL2L1.Western blot analysis confirmed the intervention effect of 18β-GRA on GC cells,MRPL35,TP53,and BCL2L1 showed dose-dependent up/down-regulation,and the expression of COPS5,BAX,and BAD also increased/decreased with the change of 18β-GRA concentration.CONCLUSION 18β-GRA can inhibit the proliferation of GC cells by regulating MRPL35,COPS5,TP53,BCL2L1,BAX,and BAD.

18β- glycyrrhetinic acid inhibits apoptosis of renal tubular epithelial cells via enhancing level of BMP-7 epigenetically through targeting HDAC2

Cisplatin （CP） , a highly effective and widely used chemotherapeutic agent, has a major limitation for its nephrotoxicity. We recently identified a novel strategy for attenuating its nephrotoxicity in chemotherapy by an ef- fective adjuvant via epigenetic modification through targeting Histone deacetylase 2 （HDAC2）. Glycyrrhizic acid （GA） ,a major active component of Licorice, was described here for its new application. Molecular docking and Surface Plasmon resonance （SPR） assay firstly reported that 18βGA, GA metabolite in vivo, could directly bind to HDAC2 and prevent HDAC2 activation. The effects and mechanisms of GA and its major metabolite 18βGA were assessed in CP-induced acute kidney injury （AKI） in C57BL/6 mice, and in CP-treated HK-2 and mTEC cells lines. Terminal deoxynucleotidyl transferase dUTP nick end labeling （TUNEL） and flow cytometry （FCM） results confirmed that GA and 18βGA could inhibit apoptosis of renal tubular epithelial cells induced by CP in vivo and in vitro. Western blot and immunofluorescence results demonstrated that the expression of bone morphogenetic protein- 7 （BMP-7） , a protective molecule in renal inflammation, was clearly induced by 18βGA in AKI models while siR- NA BMP-7 could reduce the inhibitory effect of 18βGA on apoptosis. Results of current study indicated that 18βGA inhibited apoptosis of renal tubular epithelial cells via enhancing level of BMP-7 epigenetically through targeting HDAC2, therefore protecting against CP-induced AKI. These available evidence, which led to an improved under- standing of molecular recognition, suggested that 18βGA could serve as a potential clinical adjuvant in chemothera-

HDAC抑制剂对脉络膜黑色素瘤细胞系C918细胞增殖的影响及相关机制

目的:阐明组蛋白去乙酰化酶(HDAC)抑制剂辛二酰苯胺异羟肟酸(SAHA)对脉络膜黑色素瘤(CM)细胞系C918细胞增殖的影响并探讨相关机制。方法:使用倒置荧光显微镜观察不同浓度SAHA(0.625、1.25、2.5μmol/L)对C918细胞形态的影响;CCK-8法观察C918细胞活力的变化;细胞平板克隆形成实验和EdU染色法观察SAHA对C918细胞增殖的影响;同时,Western blot检测细胞增殖相关蛋白c-Myc、细胞周期蛋白CyclinA2和CDK2以及HDAC7和成纤维细胞生长因子18(FGF18)的表达。结果:与空白对照组比较,光镜下见SAHA可减小C918的细胞密度,促进细胞皱缩,且随着SAHA浓度的增加对细胞的抑制作用也增强;CCK-8法检测结果显示SAHA浓度依赖性抑制C918细胞活力,2.5μmol/L浓度时抑制率达80%;Western blot结果表明SAHA可呈浓度依赖地降低C918细胞中的增殖蛋白c-Myc、细胞周期蛋白CyclinA2和CDK2的表达;另外,1.25μmol/L SAHA显著降低EdU染色阳性细胞数和细胞克隆数。更为重要的是,与空白对照组相比,SAHA能浓度依赖地降低HDAC7和FGF18的表达。结论:SAHA能够通过抑制HDAC7/FGF18信号通路抑制CM细胞系C918细胞的增殖。

甘草酸18H差向异构体的比较研究

本文对2个甘草酸差向异构体的物理化学性质包括GLC,UV,IR,^(1)HNMR,^(13)CNMR,MS,CD及比旋光度等进行了比较分析,并对它们的抗肝损伤作用和毒性作了实验观察。结果表明,两者物理化学性质酷似,但比旋光度,CD及^(1)HNMR,^(13)CNMR等有明显差别。抗肝损伤及急性毒性实验证明,18α—甘草酸比18β—甘草酸有更强的抗肝损伤作用,毒性也低于后者。

维甲酸降低放射性肺损伤大鼠肺组织中IL-18 mRNA及蛋白的水平

观察IL 18在放射性肺损伤大鼠肺组织的变化及维甲酸对其影响。健康雌性SD大鼠 6 0只随机分为 3组 :正常对照组 (C组 )、单纯照射组 (R组 )、维甲酸治疗组 (W组 ) ,每组 2 0只。后 2组动物行直线加速器全胸部照射 ,单次剂量 15Gy ,距离 1m ,照射面积 4.5cm× 4.5cm ,剂量率 2Gy/min ,W组维甲酸灌服剂量 2 0mg/kg ,C、R组以等量生理盐水灌服直至活杀。用免疫组化染色、原位杂交、图像分析的方法观察IL 18在放射性过程肺中的变化特点。IL 18免疫组化在照射后 30、6 0d明显增强 (P <0.0 1) ,W组 5、30、6 0d明显减弱 (P <0.0 1)。IL 18mRNA在照射后15d明显增强 (P <0 .0 5 ) ,W组 5、15、6 0d明显减弱 (P <0.0 1)。IL 18参与放射性肺损伤的发生、发展。而维甲酸无论从转录水平还是蛋白质水平都能有效抑制IL 18。

神经诱向生长因子18kD蛋白的纯化

提取与纯化诱向生长因子是神经生物化学研究中的一个重要课题．采用自然系统凝胶电泳，分离周围神经损伤过程中产生的具有诱向生长作用的１８ｋＤ蛋白，再以等电聚焦凝胶电泳与神经组织联合培养，揭示了ｐＩ为５．２的１８ｋＤ蛋白具有诱神经生长的作用．经高效液相色谱仪分析获得较纯的１８ｋＤ诱向因子．蛋白／多肽测序仪检测，１８ｋＤ蛋白Ｎ端氨基酸序列为：ＰＥＰＡＷＳＡＰＡＰ．

18-α甘草酸对大鼠四氯化碳慢性肝损伤的治疗作用

目的观察18-α甘草酸(18-α-GA)对CCl4引起的大鼠慢性肝损伤的治疗作用。方法大鼠皮下注射25%CCl4橄榄油2 mL/kg,每周2次,连续13周,给药组于第5周起分别腹腔注射18-α-GA 15、30、60 mg/kg,每日1次,连续至第13周。于末次给药24 h后,处死动物,取血分离血清或血浆,测ALT、AST、总蛋白、白蛋白、球蛋白、唾液酸、一氧化氮及透明质酸。取肝组织测定羟脯氨酸含量并作病理学检查。结果 18-α-GA能改善CCl4引起慢性肝损伤大鼠的肝功能,降低NO水平,减轻肝组织炎症活动度及纤维化程度。结论 18-α-GA对CCl4引起大鼠慢性肝损伤具有治疗效果。

DHA高产菌Schizochytrium sp.FJU512的分离及其18S rRNA基因序列比较分析

采用松花粉垂钓法分离到一株Docosahexaenoicacid(DHA)高产菌FJU 512.该菌株DHA含量高(占总脂肪酸的56. 24 % ),其它长链杂酸含量少(仅有docosapentaenoicacid, DPA),极具开发应用价值.高密度培养可获得33gL-1生物量.该菌株行二分裂生长,没有分生胞子.对其18SrRNA基因进行了克隆测序并登录GenBank(AY758384).依据18SrRNA基因建立的系统进化树表明:该菌与Schizochytriumlimacinum具有紧密的亲源关系.

18α甘草酸对D-氨基半乳糖引起的大鼠急性肝损伤治疗作用

目的观察18α甘草酸(18α-GA)对D-氨基半乳糖(GalN)引起大鼠急性肝损伤的治疗作用。方法 SD大鼠60只,随机分为6组,除阴性对照组外,所有动物同时腹腔注射10%GalN溶液500 mg/kg,给药组于GalN处理前3 d分别腹腔注射18α-GA 15、30、60 mg/kg,每日一次,GalN处理30 h后取血测定血清ALT、AST,并取肝左叶作病理组织学观察。结果 18α-GA能明显抑制急性肝损伤大鼠血清转氨酶的活力,并减轻肝脏病理损伤。结论 18α-GA对GalN引起大鼠急性肝损伤具有防治效果。

检测IL-17和IL-18水平在纤维增生性疾病中的意义

目的探讨各种纤维增生性疾病患者血清中白细胞介素-17(IL-17)、白细胞介素-18(IL-18)以及透明质酸(HA)、层黏蛋白(LN)、Ⅳ型胶原蛋白的水平,并分析IL-17、IL-18与肝纤维化的以上3项指标的相关性。方法各种肝病患者包括自身免疫性肝病13例,急性暴发性肝炎19例,慢性病毒性肝炎22例,肝纤维化或肝硬化25例,肝癌18例,胃癌9例。30例健康献血者作为正常对照组。血清中IL-17和IL-18水平检测方法为单克隆抗体夹心法酶联免疫吸附试验(ELISA),HA、LN、Ⅳ型胶原蛋白也采用ELISA方法。结果106例肝病患者及胃癌患者血清中IL-17的水平较正常对照组均有升高(P<0.01),IL-18水平除了在自身免疫性肝病和急性暴发性肝炎中有升高外,而在慢性病毒性肝炎、肝纤维化、肝癌和胃癌中较正常对照均有不同程度的降低(P<0.05)。同步检测HA、LN、Ⅳ型胶原蛋白水平,发现此3项指标变化水平与IL-17水平变化呈正相关,而与IL-18水平无明显关系。结论慢性肝病患者血清中IL-17水平与疾病的严重程度呈正相关,IL-18除在自身免疫性肝病和急性暴发性肝炎中有升高外,在慢性病毒性肝炎、肝纤维化、肝癌及胃癌中均有明显的降低,其原因和意义有待于阐明。

亲水性C_(18)硅胶反相色谱柱同时分离测定红茶中的有机酸

目的使用亲水性C18硅胶反相色谱柱同时分离测定红茶中11种有机酸。方法经ACCHROM XAqua C18柱（4.6 mm×150 mm,5μm）分离,以0.1%三氟乙酸-乙腈为流动相梯度洗脱,流速1.0 mL/min,柱温25℃,检测波长214 nm。结果 11种有机酸在13 min内实现基线分离,平均回收率为92.07%101.64%,相对标准偏差为0.54%1.93%,各有机酸线性相关系数r】0.9986。对不同产地6个红茶样品进行测定,云南凤庆红茶样品有机酸含量最高（668.62 mg/L）,锡兰红茶样品含量最低（386.67 mg/L,）;红茶有机酸以草酸为主,含量范围在119.67193.18 mg/L;乳酸（0193.43 mg/L）和乙酸（36.62193.98 mg/L,）含量在不同产地红茶样品中相对差异较大。结论本实验建立了一种较准确、高效、简便的茶叶有机酸检测技术与方法,运用此方法测定不同产地红茶有机酸含量并分析与比较不同红茶的有机酸组分差异性,并为红茶品质风味的审评及加工工艺改良提供一定数据参考。

高产DHA海洋真菌Thraustochytrium sp.FJN-10脂肪酸的组型及其18S rDNA序列分析

采用松花粉垂钓法分离到一株 Docosahexaenoic acid (DHA)高产菌 FJN 10。该菌株长链高度不饱和脂肪酸的组成为DHA(43.2%)和花生酸(17.5%)。高密度培养获得 33.0 g/L生物量。该菌株生活史中有营养细胞、孢子囊和孢囊胞子。对其 18S rRNA基因进行了克隆测序,并登录 GenBank(AY773276)。依据18S rRNA 基因建立的系统进化树分析表明:该菌与 Thraustochytrium sp. CHN 和 Thraustochytrium spMBIC11092具有紧密的亲源关系。

高产DHA海洋真菌Thraustochytrium sp.N4-103脂肪酸组成及其18SrRNA基因的克隆与序列分析

采用松花粉垂钓法分离到一株docosahexaenoicacid(DHA)高产菌Thraustochytriumsp.N4-103.该菌株细胞油脂的脂肪酸组型为47.3%DHA,11.6%C22∶5(n-6),9.4%C20∶5(n-3),9.1%C20∶4(n-6)和22.6%C16∶0;单细胞油脂由42.6%极性脂肪,45.3.%中性脂肪和12.1%糖脂组成.细胞生长与DHA合成的最佳条件:碳源为葡萄糖,氮源为酵母膏,温度为25℃.利用PCR技术分离得到N4-103菌株18SrRNA基因并进行了克隆测序,序列含有Thraustochytrids的特征插入片段.依据18SrRNA基因序列所构建的遗传进化树表明该菌是一株与Thraustochytriumsp.KK17-3具有紧密亲源关系的未报道的破囊壶菌.

稀土(铕-铽)-18冠6-对苯二甲酸配合物的荧光性能

以对苯二甲酸(L′)为桥联配体,18冠6(L)为配体,稀土(Eu Tb)为中心离子,合成了一系列超分子化合物,对其进行了元素分析,红外光谱及荧光性能测量。确定了配合物的组成为(Eu1-xTbx)2L2L′(ClO4)4·H2O(6+3x);推测出Eu3+离子直接与冠醚氧原子配位,而较小半径的Tb3+与18冠6则通过H2O配位。H2O分子与冠醚氧原子以氢键形式连结,对苯二甲酸以双齿形式桥联两个稀土离子冠醚配合物,形成双核结构单元;在此配合物中,Tb3+离子对Eu3+离子的发光有一定的敏化作用,而Eu3+离子对Tb3+离子的荧光却有强的猝灭作用。

18α-甘草酸和18β-甘草酸抗大鼠肝纤维化作用比较研究

目的以γ-干扰素(IFN-γ)为阳性对照药,比较研究18α-甘草酸(18α-GL)、18β-甘草酸(18β-GL)的抗大鼠肝纤维化作用。方法以二甲基亚硝胺(DMN)腹腔注射诱导大鼠肝纤维化模型,染毒开始及染毒后5周分别用18-αGL,18-βGL,IFN-γ预治疗和治疗肝纤维化。观察各组肝羟脯氨酸(HyP)、血清透明质酸(HA)水平,血清生化指标、病理及肝纤维化程度。结果与IFN-γ比较,18-αGL,18β-GL差相异构体预治疗组和治疗组抗肝纤维化作用与其相近,治疗组明显优于染毒对照组;18α-GL治疗组明显优于18β-GL组。结论18-αGL,18β-GL差相异构体有较好的抗肝纤维化作用,且18α-GL明显优于18β-GL。