两种耐热磷酸化酶的构建及高效催化合成红景天苷

目的:使用表达耐热蔗糖磷酸化酶的大肠杆菌重组工程菌E. coli BL21/pET-Spase和耐热纤维二糖磷酸化酶的大肠杆菌重组工程菌E. coli BL21/pET-Cpase,发酵培养后粗酶液作为催化剂,以价格低廉的蔗糖为原料合成红景天苷。方法:分别构建耐热蔗糖磷酸化酶和耐热纤维二糖磷酸化酶大肠杆菌重组菌,然后将重组菌、蔗糖、酪醇和磷酸混合,得到反应混合物,使反应混合物在45℃下转化,而产生红景天苷。结果:在耐热蔗糖磷酸化酶酶液1200 U/L、耐热纤维二糖磷酸化酶酶液500 U/L、蔗糖110 g/L、酪醇30 g/L和磷酸50 m M的浓度下,反应条件为pH 7.0、温度45℃、转速50转/分、反应时间32小时后,红景天苷浓度达到23.7 g/L。结论:本研究使用蔗糖磷酸化酶和纤维二糖磷酸化酶联合催化的工艺,成功地高收率合成了红景天苷。同时,本研究构建的耐热磷酸化酶酶活高,处理简单,为拓展糖苷类似物的合成提供了一种新的方法。     

红景天苷对高原缺氧大鼠认知功能障碍的治疗作用及其可能机制

目的：探讨红景天苷（Sal）对高原缺氧大鼠认知功能障碍的治疗作用及其可能机制。方法：将30只成年雄性SD大鼠随机分为健康对照组、模型组（Model组）、Sal[按体重1g／（kg·d）]治疗组（sal组）。采用Morris水迷宫实验方法捡测缺氧后大鼠学习记忆功能变化,同时检测脑组织匀浆中超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH—PX）、谷胱甘）lk（GSH）、丙二醛（MDA）的水平。结果：（1）模型组大鼠寻找平台的潜伏期明显长于对照组,具有统计学意义（P〈0．05）,Sal组寻找平台的潜伏期相对于模型组显著缩短（P〈0．05）。撤离平台后,模型组大鼠在平台所在象限的停留时间明显短于对照组（P〈0．05）,Sal治疗后大鼠在平台所在象限的停留时间较模型组显著延长（P〈0．05）。（2）模型组SOD、GSH—PX、GSH显著下降,MDA明显增高,Sal干预组SOD、GSH．PX、GSH显著增高,而MDA明显下降,具有统计学意义（P〈O．05）。结论：Sal可改善高原缺氧大鼠认知功能,其可能机制是通过减轻海马区的氧化应激反应减轻海马区的损伤,从而实现改善认知功能。     

Mechanism of salidroside relieving the acute hypoxia-induced myocardial injury through the PI3K/Akt pathway

ObjectiveThe objective was to investigate the anti-inflammatory effects of salidroside through the PI3K/Akt signaling pathway and its protective effects on acute hypoxia-induced myocardial injury in rats.MethodsA total of 24 healthy Sprague-Dawley male rats were selected as the experimental subjects. All rats were divided into 4 groups by using the random number table method, with 6 rats in each group. The groups included the normal control group, the salidroside group, the hypobaric hypoxia group, and the hypobaric hypoxia + salidroside group. Rats in the salidroside group were fed in the original animal laboratory and were intragastrically administered with salidroside every morning at a dosage of 35 mg/kg. Rats in the normal control group were intragastrically administered with an equal dosage of saline. Rats in the hypobaric hypoxia + salidroside group were intragastrically administered with salidroside every morning at a dosage of 35 mg/kg, who were fed in the hypoxic experiment module for animals. The altitude was increased to 4000 m, and the rats were kept in the module for 24 h. Rats in the hypobaric hypoxia group were intragastrically administered with an equal dosage of saline in the same environment, and the altitude was increased to 4000 m after administration. Parameters of blood gas analysis, histopathological changes in cardiac tissues, cardiac indexes, and inflammatory factors IL-6 and TNF-α levels of rats in groups were compared.Results1. The cardiac indexes of rats in groups were compared. The differences between the hypobaric hypoxia group and the hypobaric hypoxia + salidroside group were statistically significant (P < 0.05). 2. The results of blood gas analysis of rats in groups were compared. The differences between the hypobaric hypoxia group and the hypobaric hypoxia + salidroside group were significantly different (P < 0.05). 3. In the hypobaric hypoxia group, the myocardial cells of rats were arranged disorderly and shaped differently, with cases such as edema, degeneration, necrosis, nucleus pyknosis, and massive infiltration of inflammatory cells. In the hypobaric hypoxia + salidroside group, the above-mentioned pathological changes in myocardial cells were relieved. 4. Compared with the hypobaric hypoxia group, in the hypobaric hypoxia + salidroside group, the concentrations of IL-6 and TNF-α in rats decreased apparently, and the differences were statistically significant (P < 0.05).ConclusionSalidroside had the repairing and protective effects on the hypobaric hypoxia-induced myocardial injuries in rats. The application of salidroside could reduce the inflammatory responses of rats with hypobaric hypoxia-induced myocardial injuries through PI3K/Akt signaling pathway, thereby protecting the myocardial cells.     

帕里红景天的化学成分研究

从帕里红景天根茎的石油醚和乙醇提取部分共分得１４种结晶性化合物,经光谱分析和化学反应,分别鉴定为二十二醇、二十六酸、十九醇、β－谷甾醇、二十九醇、红景天甙、麦芽糖、棉皮素－８－葡萄糖甙、胡萝卜甙、酪醇、咖啡酸、没食子酸、形花内酯和新化合物帕里甙。     

Preparation of salidroside with n-butyl β-D-glucoside as the glycone donor via a two-step enzymatic synthesis catalyzed by immobilized β-glucosidase from bitter almonds

β-Glucosidase from bitter almonds was immobilized on epoxy group-functionalized beads for catalyzing salidroside synthesis in a two-step process with n-butyl-β-D-glucoside (BG) as the glucosyl donor. The formation of salidroside ((0.59?±?0.02) M) at a yield of 39.04%±1.25% was accomplished in 8?h by the transglucosylation of immobilized β-glucosidase at pH 8.0 and 50?°C when the ratio of BG to tyrosol was 1:2 (mol/mol). A study on the influence of different glycosyl acceptors demonstrated that the yield of the glucosylation reaction of phenylmethanol and cyclohexanol was higher than that of either phenol or cyclohexanol. This may account for the selectivity of the immobilized enzyme towards the alcoholic hydroxyl group of tyrosol in the salidroside synthesis reaction. A study on the synthesis of BG via the reverse hydrolysis of immobilized β-glucosidase showed that a yield of 78.04%±2.2% BG can be obtained with a product concentration of (0.23?±?0.015) M.     

Isolation and genotype-dependent, organ-specific expression analysis of a Rhodiola rosea cDNA encoding tyrosine decarboxylase

Tyrosine decarboxylase (TyrDC) is an important enzyme in the secondary metabolism of several plant species, and was hypothesized to play a key role in the biosynthesis of salidroside, a pharmacologically valuable compound of roseroot. A 1520 bp cDNA was cloned and sequenced, and turned out to contain an ORF of 963 bp, which encodes a protein of 320 amino acids.The expression of the gene was studied by real-time PCR from leaves and roots of both high and low salidroside producer genotype of roseroot. The gene expression analysis showed the gene to be expressed in leaves as well as in roots; however, the expression was significantly higher in roots, which coincides with the fact that salidroside accumulates preferentially in the underground parts of the plant. The expression was also higher in the line accumulating high levels of salidroside, compared to the line with lower salidroside content. The difference in the expression intensity suggests a decisive role for this enzyme in the salidroside biosynthesis.     

Pharmacological studies on the sedative and hypnotic effect of salidroside from the Chinese medicinal plant Rhodiola sachalinensis

This is the preliminary study of sedative and hypnotic activity of salidroside (a major component of Rhodiola sachalinensis) in mice by using synergism with pentobarbital as an index for the hypnotic effect. Loss of the righting reflex was used to determine the start of sleep. Sleep latency and sleeping time were evaluated in this experiment. The results showed that salidroside could obviously shorten the sleep latency and prolong the sleeping time of mice produced by pentobarbital sodium (55 mg/kg, i.p.). Salidroside produces significant sedative-hypnotic effect. The dose-effect relationship is remarkable.     

MADP,a salidroside analog,protects hippocampal neurons from glutamate induced apoptosis

Aims

To investigate the anti-apoptotic effect of MADP, an analog of salidroside, against glutamate induced apoptosis in the cultured rat hippocampal neurons.

Main methods

Cytotoxicity was determined by the MTT method and lactate dehydrogenase release to the medium. Cell apoptosis was evaluated by Hoechst 33342 staining, TUNEL assay and flow cytometric analysis. Western blotting was applied for detecting protein levels of cellular signaling molecules.

Key findings

Our results showed that glutamate exposure significantly induces cell apoptosis, whereas the pretreatment of salidroside or MADP remarkably improves cell viability. Most importantly, the anti-apoptotic effect of MADP against glutamate insult is superior to salidroside. To explore the involved mechanisms, we measured some pro-apoptotic and anti-apoptotic protein levels, and several cell survival signaling pathways were analyzed as well. No visible alterations in Bcl-2 and Bax protein levels were observed by MADP or salidroside. Akt and JNK phosphorylation was robustly stimulated by MADP in the glutamate-treated neurons. Salidroside treatment results in a slight activation in Akt, while no significant alteration in JNK activity was observed.

Significance

MADP exhibits higher capacity to attenuate glutamate induced cell apoptosis in the cultured rat hippocampal neurons, suggesting that MADP might be a better candidate than salidroside for developing novel drugs treating neuron loss associated disorders.     

红景天苷调节AMPK/mTOR/ULK1信号通路对结肠癌SW480细胞裸鼠的肝脏损伤的影响

摘要 目的：探讨红景天苷（Sal）调节单磷酸腺苷活化蛋白激酶（AMPK）/哺乳动物雷帕霉素靶蛋白（mTOR）/Unc51样激酶1（ULK1）信号通路对结肠癌SW480细胞裸鼠肝脏损伤的影响。方法：通过皮下注射SW480细胞悬浮液建立肝转移裸鼠模型,将造模后的裸鼠随机分为模型组、Sal低剂量（Sal-L,50 mg/kg Sal）组、Sal中剂量（Sal-M,100 mg/kg Sal）组、Sal高剂量（Sal-H,200 mg/kg Sal）组,Sal-H+AMPK抑制剂（Compound C,200 mg/kg Sal+10 mg/kg Compound C）组,以未接种SW480细胞悬液的裸鼠作为对照组。腹部主动脉取血,检测裸鼠血清中丙氨酸氨基转移酶（AST）、天冬氨酸氨基转移酶（ALT）水平;处死裸鼠,检测肝转移瘤数目及肝脏重量;HE染色观察肝脏组织病理变化;qRT-PCR检测肝脏组织中AMPK、mTOR、ULK1 mRNA表达水平;Western blot检测肝脏组织中自噬（Beclin1、p62）蛋白及通路相关蛋白表达。结果：与对照组相比,模型组裸鼠组织中出现肝转移瘤,肝脏重量、AST、ALT水平、mTORmRNA、ULK1 mRNA、p62表达显著增加（P<0.05）;Beclin1、AMPK mRNA及蛋白表达显著降低（P<0.05）;与模型组相比,Sal-L、Sal-M、Sal-H组肝转移瘤数目、肝脏重量、AST、ALT水平、mTORmRNA、ULK1 mRNA、p62表达显著降低（P<0.05）;Beclin1、AMPK mRNA及蛋白表达显著增加（P<0.05）;与Sal-H组相比,Sal-H+Compound C组肝转移瘤数目、肝脏重量、AST、ALT水平、mTORmRNA、ULK1 mRNA、p62表达显著增加（P<0.05）;Beclin1、AMPK mRNA及蛋白表达显著降低（P<0.05）。结论：Sal可通过减少裸鼠肝转移瘤形成,保护裸鼠肝脏,其机制可能与激活AMPK/mTOR/ULK1信号通路,促进肝脏自噬有关。