Study of kinetics with respect to action of flavonoid from mulberry leaves on inhibition of activity of tyrosinase

采用超声波辅助法,以体积分数为60%的乙醇水溶液从新疆桑叶粉末中提取桑叶黄酮。以l-多巴为底物,采用酶动力学方法研究该提取物对酪氨酸酶的抑制作用。实验结果表明,桑叶黄酮提取物对酪氨酸酶有较强的抑制作用,其IC50为0.2 g·l-1。其对酪氨酸酶的抑制作用表现为可逆效应,抑制类型为混合型抑制,对游离酶的抑制常数(kI)和对酶-底物络合物的抑制常数(kIS)分别为366和873 Mg·l-1。dPPH实验显示新疆桑叶黄酮提取物具有一定的抗氧化作用,对dPPH自由基氧化作用相对活性的IC50为25 Mg·l-1,与VC效果相当。Flavonoid was extracted from powder of mulberry leaves planted in Xinjiang with 60%( vol) ethanol aqueous solution under assistance of ultrasonic wave.Adopting enzymatic kinetic method,inhibitory action of the extract on tyrosinase activity was studied using L- dopa as the substrate.Results showed that the flavonoid extract displays rather strong inhibitory action on activity of tyrosinase.Its IC50 was estimated as 0.2 g·L- 1.The inhibition mechanism was studied and it was found that the reaction is reversible and type of the inhibition belongs to the mixed type,with the inhibition equilibrium constants for inhibitor binding with free enzyme KI and with enzyme- substrate complex KISwere determined as 366 and 873 mg·L- 1respectively.The DPPH( 1,1-diphenyl-2-picrylhydrazyl) radical test results showed that the flavonoid extract has the antioxidant activity to a certain extent.The IC50 is 25 mg·L- 1that is similar to vitamin C.新疆维吾尔自治区高校科研计划科学研究重点资助项目(XJEDU2012I30); 新疆师范大学校级重点学科招标课题资助项目(XJMB-1

Inhibition of mushroom tyrosinase by flavonoid from Sorbus tianschanica Ruper in Xinjiang

以新疆天山花楸的茎为材料,采用超声波辅助法提取得到天山花楸黄酮类物质。以l-多巴为底物,运用酶动力学方法研究黄酮类物质对酪氨酸酶的抑制作用。结果表明:天山花楸黄酮类物质对酪氨酸酶有较强的抑制作用,导致酪氨酸酶二酚酶活力下降50%所需的提取物浓度(IC50)值为0.27 Mg/M l。对酪氨酸酶的抑制显示可逆的效应,抑制类型为混合型,对游离酶的抑制常数(kI)和酶-底物配位化合物的抑制常数(kIS)分别为0.218和0.313Mg/M l。1,1-二苯基-2-三硝基苯肼自由基(dPPH·)实验显示天山花楸黄酮类物质具有一定的抗氧化作用,引起dPPH·活性下降50%的黄酮类物质浓度(IC50)为0.18 Mg/M l。本研究为进一步开发利用天山花楸中的果蔬保鲜及美白成分提供了理论依据。Flavonoid was extracted from powder of Sorbus tianschanica Ruper stems under assistance of ultrasonic wave.Adopting enzymatic kinetic method,inhibitory action of flavonoid extract on the tyrosinase activity was studied using L-DOPA as substrate.Results showed that flavonoid extract from Sorbus tianschanica Ruper inhibited tyrosinase.Its IC50 was estimated as 0.27 mg / m L.The inhibition mechanism was studied and it was found that the reaction was reversible and type of the inhibition belonged to the mixed-type.The inhibition equilibrium constants for inhibitor binding with free enzyme KI and with enzyme-substrate complex KISwere determined as 0.218 and 0.313 mg / m L,respectively.The DPPH( 1,1-diphenyl-2-picrylhydrazyl) radical test results showed that flavonoid extract from Sorbus tianschanica Ruper had the antioxidant activity to a certain extent and the inhibitor concentration leading to 50% DPPH· free radical activity loss( IC50) was determined to be 0.18 mg /m L.The above study provides a basis for further development of the fruits and vegetables preservatives and whitening ingredient in the Sorbus tianschanica Ruper.国家自然科学基金(31260213); 新疆维吾尔自治区高校科研计划科学研究重点项目(XJEDU2012I30); 新疆维吾尔自治区教育厅重点实验室开放基金项目(XJSD2013-06

柴郁地仙方对围绝经期抑郁症模型大鼠行为学及海马BDNF、TrkB蛋白表达的影响

目的观察柴郁地仙方对围绝经期抑郁症(perimenopausal depressive disorder, PDD)模型大鼠行为学及海马脑源性神经营养因子(brain derived neurotrophic factor, BDNF)、酪氨酸激酶B受体(tropomyosin receptor kinase B, TrkB)蛋白表达的影响,探讨其抗围绝经期抑郁症的作用机制。方法 48只3～4月龄雌性SD大鼠随机分为假手术组、模型组、阳性对照组、柴郁地仙方低、中、高剂量组,共6组,每组8只。假手术组行假手术,其余组行卵巢去势术后孤养并予以28天慢性轻度不可预见性应激(chronic unpredictable mild stress, CUMS)建立围绝经期抑郁症模型。CUMS第1天起假手术组、模型组灌服生理盐水,阳性对照组灌服盐酸氟西汀合戊酸雌二醇,中药治疗组灌服柴郁地仙方低、中、高不同浓度的汤药,其浓度分别为:0.38、0.76、1.52 g/mL,每天1次。应激过程中观察大鼠行为学及体重变化,并通过Morris水迷宫实验评价大鼠空间学习和记忆能力,应用免疫印迹法检测大鼠海马BDNF、TrkB蛋白表达情况。结果与假手术组比较,模型组大鼠体重增长缓慢,旷场实验得分及糖水偏好率均明显降低(P0.05)。结论柴郁地仙方可改善PDD模型大鼠行为学、体重水平及水迷宫的空间学习和记忆能力,其作用机制可能是通过提高大鼠海马中BDNF、TrkB蛋白表达量发挥的。福建省计生委中医药科研基金资助项目(No.wzpw201307);;福建省自然科学基金计划项目(No.2017J01147

小檗碱对口服降糖药糖尿病患者的胃肠激素及肠道菌群的影响

目的:探讨盐酸小檗碱对2型糖尿病(T2DM)胃泌素(GAS)、胰高血糖素(GLC)及肠道菌群的影响。方法:以25例口服降糖药治疗的T2DM患者为治疗组,对照组选取健康人群10例。T2DM患者常规治疗,同时给予盐酸小檗碱500 mg,每日3次,连续12周。分别于0、4、8、12周检测血糖、GAS、GLC,于0、12周采集清晨空腹粪便进行粪便菌群培养。结果:治疗组治疗后FPG及餐后1hPG有不同程度的下降(P<0.05)。治疗前后治疗组GAS、GLC水平均明显高于对照组(P<0.05)。治疗组治疗后GAS水平持续升高(P<0.05)。治疗后治疗组厚壁菌门明显低于治疗前(P<0.05)。治疗后治疗组大肠杆菌属明显高于治疗前(P<0.05)。治疗前治疗组柔嫩梭菌属明显低于对照组(P<0.05)。治疗后治疗组厚壁菌门明显低于对照组(P<0.01)。治疗前后治疗组拟杆菌明显低于对照组(P<0.05)。结论:小檗碱有助于改善T2DM患者胃肠激素、肠道菌群失调现象,改善糖代谢紊乱。福州市卫计委创新团队课题(2015-S-wt2);;福建省中青年骨干科技计划项目(2015-ZQN-JC-37

盐酸小檗碱对糖尿病患者血糖、胃肠激素及肠道菌群的影响

目的探讨盐酸小檗碱对2型糖尿病患者胃泌素、胰高血糖素及肠道菌群的影响。方法选择我院单用胰岛素治疗的2型糖尿病患者25例为治疗组,选取同期体检中心体检健康人群10例为对照组。治疗组根据血糖情况调整胰岛素剂量,同时给予盐酸小檗碱每次500mg,tid,连续12周。分别于0、4、8、12周检测血糖、胃泌素、胰高血糖素,于0、12周采集清晨空腹粪便进行粪便菌群培养。结果治疗组治疗前后胃泌素水平均明显高于对照组(P0.05)。治疗组治疗前厚壁菌门高于治疗后及对照组水平(P<0.05);治疗组治疗前乳酸杆菌属、拟杆菌属明显低于治疗后水平(P<0.05);治疗组治疗前拟杆菌属、柔嫩梭菌属低于对照组水平(P<0.05)。结论 2型糖尿病患者存在胃肠激素及肠道菌群失调,盐酸小檗碱有助于改善糖尿病患者胃肠激素、肠道菌群失调现象。福州市卫生计生系统科技计划项目(2015-S-wt2);;福建省中青年骨干科技计划项目(2015-ZQN-JC-37

小檗碱对不同程度2型糖尿病患者的胃肠激素及肠道菌群的影响

小檗碱又称黄连素,是中药黄连所含的主要生物碱,具有广谱抗菌的药理作用,多用于治疗胃肠道细菌性感染。近年来大量研究显示,小檗碱具有良好的降糖、减轻胰岛素抵抗、干预胃肠道激素的作用。因此,本研究采用小檗碱进行为期12周的临床干预治疗,观察小檗碱对不同程度2型糖尿病患者胃泌素、胰高血糖素及肠道菌群的作用,为2型糖尿病患者的防治提供新思路。1临床资料1.1一般资料选择2017年1-10月就诊于厦门大学福州市卫生计生委创新团队课题(2015-S-wt2);;福建省中青年骨干科技计划项目(2015-ZQN-JC-37

Preparations and Electrochemical Properties of BC/CoNi2S4@PPy Flexible Composites for Supercapacitors

本文采用溶剂热、原位聚合和真空抽滤相结合的方法制备了用于超级电容器的细菌纤维素/镍钴硫化物/聚吡咯(BC/CoNi2S4@PPy)柔性电极材料,通过X射线衍射、场发射扫描电镜、红外光谱、氮气吸脱附、拉伸强度和接触角表征了材料的形貌结构、组成、机械性能和亲水性,并采用循环伏安法和恒电流充放电测试了复合材料的电化学性能。结果表明,表面含氧官能团丰富的BC纤维网络结构对氧化还原活性物质CoNi2S4的生长和导电聚合物PPy的分布具有引导作用,CoNi2S4均匀分布在BC网络中,且PPy均匀包覆在BC纤维和CoNi2S4纳米球表面构成具有丰富孔隙结构的三维导电网络,使得该复合材料具有较好的机械性(抗拉强度达28.0±0.1 MPa)、亲水性(对6 mol·L-1 KOH的瞬间接触角为43.6°)及良好的导电性。该电极材料在1 A·g-1下比电容高达2670 F·g-1,充放电循环10000次后比电容的保持率为82.73%,且经1000次反复弯曲后电化学性能保持不变。此外,将其与活性炭组成的非对称超级电容器,在1 A·g-1下比电容为1428 F·g-1,最高能量密度和功率密度分别达49.8 Wh·kg-1和741.8 W·kg-1。Flexible supercapacitor is one of the most promising energy storage devices for portable and wearable electronic products due to its advantages of high power density, fast charging and long cycle life. Therefore, self-supporting flexible electrode materials with high performance have attained more and more attention both in academia and in industry recently. In this work, using bacterial cellulose (BC) as a flexible substrate, the bacterial cellulose/nickel-cobalt sulfide@polypyrrole (BC/CoNi2S4@PPy) flexible composites with three-dimensional porous network and good conductivity were prepared by a combined solvothermal-in-situ polymerization-vacuum filtration method. The samples were characterized by X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectrometry, N2 physisorption, tensile strength and contact angle measurements. Their electrochemical performances were tested by cyclic voltammetry, galvanostatic charge/discharge testing and electrochemical impedance spectroscopy. The results show that the three-dimensional porous network of BC fibers with rich oxygen-containing surface groups play a guiding role in the growth of the redox active material CoNi2S4 and the distribution of conductive polymer PPy, resulting in uniformly distributed CoNi2S4 nanospheres in the network of BC fibers, both coated evenly with a layer of conductive PPy. The resulting BC/CoNi2S4@PPy composites, a three-dimensional conductive network with high porosity, displayed good mechanical property (tensile strength up to 28.0±0.1 MPa), hydrophilicity (the instantaneous contact angle in 6 mol·L-1 KOH is 43.6°), as well as excellent electrochemical performance. The specific capacitance of the flexible BC/CoNi2S4@PPy was 2670 F·g-1 at 1 A·g-1 in a three-electrode system, and retained 82.7% after 10000 charge and discharge cycles. In addition, the electrochemical performance remained unchanged after 1000 times of repeated bending. In an asymmetric supercapacitor composed of BC/CoNi2S4@PPy and activated carbon, the area specific capacitance was 1428 F·g-1 at 1 A·g-1. The asymmetric supercapacitor achieved the maximum energy density of 49.8 Wh·kg-1 and power density of 741.8 W·kg-1.国家重点基础研究发展计划项目(2014CB239702);国家自然科学基金项目(21676082)通讯作者:周静红E-mail:[email protected]:Jing-HongZhouE-mail:[email protected]华东理工大学化工学院,上海 200237School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, Chin

一个新的胚胎发育调控基因的表达图式及其功能研究

利用差别杂交的方法,从银鲫原肠期胚胎SMART cDNA文库中克隆到一个新基因,其时空表达模式暗示该基因可能是一个新的胚胎发育调控因子。用生物信息学的方法搜索到斑马鱼中存在着两个基因,在序列上与我们从银鲫中克隆得到的鱼类胚胎发育调控因子高度同源,暂分别命名为138a和138b。它们串联排列于16号染色体上。设计特异于各自基因cDNA的引物, 用RT-PCR的方法确证了两个基因在斑马鱼胚胎发育过程中的表达。整体原位杂交、Western blot 和免疫荧光定位的结果显示,在斑马鱼和银鲫的胚胎发育过程中,该基因的时空表达格式很类似,暗示着它们在功能上的保守性。在胚胎发育过程中,其转录本一直定位于卵黄合胞层(YSL)