Enzymatic glycosylation of oleanane-type triterpenoids

Abstract

Glycosylation is an effective approach to improve the druggability of natural products by increasing their water solubility. In this work, we report the glycosylation of oleanane-type triterpenoids by a recombinant microbial glycosyltransferase YjiC1. A preliminary screening test indicated YjiC1 exhibited robust capabilities for O-glycosylation of triterpenoids, based on LC/MS analysis. Among the products, two new compounds (2a and 3a), together with a known one (1a), were isolated and characterized. These products exhibited improved water solubility, and 3a showed moderate anti-HIV activities at 100 μM. This reaction provides a facile and efficient approach to synthesize the glucosides of triterpenoids.     

Two new p-coumaroylated sesquiterpenoids from Pilea cavaleriei

A new p-coumaroylated santalane-type sesquiterpenoid, 8-p-coumaroyl-α-santalene (1), a new p-coumaroylated oplopanane-type sesquiterpenoid, 8-β-p-coumaroyl-oplopanone (2), and three known p-coumaroylated humulene-type sesquiterpenoids (3–5) were isolated from the ethanol extract of the whole herbs of Pilea cavaleriei. Their structures were elucidated based on the combination of 1D and 2D NMR and HRMS methods. Compound 2 was found to show anti-tuberculosis activity with MIC of 16 μg/ml.     

大鼠局灶性脑梗死后半胱氨酸天冬氨酸蛋白酶3,9的表达及白花丹参叶的干预效应

目的：观察大鼠局灶性脑梗死后促进细胞凋亡的半胱氨酸天冬氨酸蛋白酶3,9表达的变化规律及白花丹参叶的保护作用方法：实验于2004—03／06在山东省泰山医学院微循环重点实验室完成。取50只Wistar大鼠，随机分为局灶性脑梗死组和白花丹参叶预处理组两组符25只，每组义按光照后时间分为30min．12，24，48，72h等5个亚组，每亚组5只。造模前，白花丹参叶预处理组大鼠给予20g／kg白花丹参叶水提物灌服，1次／d，连续7d，然后两组同时采用光化学法制作大鼠局灶性脑梗死的模型。利用免疫组化染色技术观察局灶性脑梗死后不同时间点大鼠脑半胱氨酸天冬氨酸蛋白酶3,9表达的变化，并观察大鼠一般情况。结果：50只大鼠全部进入结果分析。①局灶性脑梗死组大鼠梗死后30min即有半胱氨酸天冬氨酸蛋白酶3，9阳性细胞出现，呈半球状向四周放射样扩展，随梗死时间的延长逐渐增多，二者行均在48h表达至高峰，但半胱氨酸天冬氨酸蛋白酶3表达更显著（P〈0．05），阳性细胞局限于梗死区周围。②预防性应用白花丹叶水提物后，大鼠出现明显的嗜睡现象，受损皮质表面积红染区、蓝染区明显减小，各时点半胱氨酸天冬氨酸蛋白酶3,9的阳性反应均明显减少，较单钝梗死组有显性差异（P〈0．05）。结论：局灶性脑梗死后可诱导仁胱氨酸天冬氨酸蛋白酶3,9的表达，白花丹参对脑梗死具有保护作用，其分子机制可能为抑制了半胱氨酸天冬氧酸蛋白酶3,9的表达。     

苏木酮A对大鼠类风湿性关节炎的治疗作用

目的探究苏木Caesalpinia sappan的活性成分苏木酮A对大鼠类风湿性关节炎(rheumatoid arthritis,RA)的治疗作用。方法以牛Ⅱ型胶原蛋白诱导建立RA大鼠模型,以苏木酮A(50mg/kg)进行干预,考察大鼠足容积变化,对大鼠踝关节组织进行病理分析,采用免疫组化考察大鼠踝关节组织中白细胞介素-6(interleukin-6,IL-6)、肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)和基质金属蛋白酶-9(matrix metalloproteinase-9,MMP-9)表达。以脂多糖诱导Raw264.7细胞建立炎症细胞模型,考察苏木酮A对Raw264.7细胞上清液中一氧化氮和IL-6水平的影响。结果苏木酮A显著降低RA大鼠足容积(P<0.05),改善RA大鼠踝关节滑膜组织损伤,抑制RA大鼠踝关节滑膜组织中IL-6、TNF-α和MMP-9的表达。苏木酮A显著抑制脂多糖诱导的Raw264.7细胞上清液中一氧化氮和IL-6水平(P<0.01)。结论苏木酮A可有效缓解大鼠RA。     

P167肽修饰的多柔比星长循环脂质体在大鼠体内的药动学和药效学

目的研究P167肽修饰对多柔比星脂质体大鼠静脉给药的体内药动学和药效学的影响。方法通过pH梯度法分别制备多柔比星长循环脂质体（DOX—SSL）和P167肽修饰的多柔比星长循环脂质体（DOX—P167一SSL）。12只sD大鼠随机分为2组,分另q尾静脉注射DOX．SSL和DOX—P167-SSL,给药剂量为2．5mg·kg-1。采用HPLC内标法测定不同给药时间的血清多柔比星浓度,用WinNonlin软件拟合并计算药动学参数。制备大鼠脑胶质瘤模型,经核磁扫描测定肿瘤体积,均匀分组,分别尾静脉注射生理盐水、DOX—SSL和DOX．P167．SSL,每组6只动物,给药剂量为2．5mg·kg-1,3d给药1次,共给药5次。以相对肿瘤增殖率（T／C％）为指标评价药效。结果DOX—SSL和DOX—P167-SSL大鼠尾静脉给药后,均符合二室模型。DOX—P167-SSL组的tl／,t1/2及AUC分别为4．89min、837．57rain、610．35min·mg·L-1,均低于DOX—SSL组的16．23、2940．48和1301．16min·mg·L-1。DOX—P167-SSL组T／C％为7．32％,而DOX—SSL组为37．07％。结论P167肽的修饰使多柔比星长循环脂质体的长循环效果降低,但药效得到明显提高,这可能与P167肽的穿透作用有关。     

Inhibition of EGFR autophosphorylation plays an important role in the anti-breast cancer efficacy of the dithiocarbamate derivative TM208

Aim： To investigate the effects of a novel dithiocarbamate derivative TM208 on human breast cancer cells as well as the pharmacoki- netic characteristics of TM208 in human breast cancer xenograft mice. Methods： Human breast cancer MCF-7 and MDA-MB-231 cells were treated with TM208 or a positive control drug tamoxifen. Cell pro- liferation was examined using SRB and colony formation assays. Cell apoptosis was analyzed with Annexin V-FITC/PI staining assay. Protein expression was examined with Western blot, ELISA and immunohistochemical analyses. MCF-7 breast cancer xenograft nude mice were orally administered TM208 （50 or 150 mg.k$1〈1-1） or tamoxifen （50 mg.kgl〈t-~） for 18 d. On d 19, the tumors were collected for analyses. Blood samples were collected from the mice treated with the high dose of TM208, and plasma concentrations of TM208 were measured using LC-MS/MS. Results： Treatment of MCF-7 and MDA-MB-231 cells with TM208 dose-dependently inhibited the cell proliferation and colony formation in vitro （the IC~o values were 36.38＋3.77 and 18.13＋0.76 pmol/L, respectively）. TM208 （20-150pmol/L） dose-dependently induced apoptosis of both the breast cancer cells in vitro. In MCF-7 breast cancer xenograft nude mice, TM208 administration dose-depend- ently reduced the tumor growth, but did not result in the accumulation of TM208 or weight loss. TM208 dose-dependently inhibited the phosphorylation of EGFR and ERK1/2 in both the breast cancer cells in vitro as well as in the MCF-7 xenograft tumor. Conclusion： Inhibition of EGFR autophosphorylation plays an important role in the anticancer effect of TM208 against human breast cancer.     

质子泵抑制剂临床治疗与骨折风险的循证评价

目的:基于长期和/或高剂量使用质子泵抑制剂(proton pump inhibitor,PPI)可能增加髋骨、腕骨及脊骨骨折的风险,对PPI增加骨折风险的相关研究进行综述和评价,探讨PPI增加骨折风险可能存在的机制,以更好地控制治疗的风险。方法:联网检索Pub Med、Cochrane Central、EMbase英文数据库和CNKI、CBM、VIP和Wan Fang Data中文数据库,纳入有关PPI使用与骨折关系的研究,终点结局设定为骨折,检索时间从入库截至2013年10月31日。根据希尔因果关系准则对PPI使用和骨折风险关联性进行分析,并用GRADE方法对文献质量进行评价。结果与结论:共检索得到英文文献619篇,中文文献142篇,其中包括9篇病例对照研究、6篇队列研究,以及6篇系统评价和Meta分析。关于PPI使用与骨质疏松骨折风险的临床研究均是观察性研究,研究的结果显示PPI长期使用可增加导致髋骨、腕骨、脊骨骨折的危险性,但是关联性并不是很强,高剂量、长疗程有更高的骨折风险。系统评价和Meta分析合并的OR值也都小于2,研究之间存在较大的异质性,按GRADE方法对纳入研究质量评价为极低质量证据。有待于更多高质量的循证证据来进一步评估发生骨折不良反应的风险。对于长期使用PPI的患者宜选择最小维持剂量,考虑间歇用药,或换用H2受体拮抗剂(H2RA)。     

脑胶质瘤治疗及其动物模型的研究进展

脑胶质瘤是原发性中枢神经细胞肿瘤中最常见并且死亡率最高的肿瘤。尽管对其研究的重视程度日渐增加,胶质瘤依然是现今最难治疗的肿瘤。许多候选药物在临床前试验有较好效果的药物在临床试验后期失败,提示动物模型的改进的必要性。随着药理学,药剂学与分子生物学研究的进展,建立科学的、可重复性好的动物模型对于胶质瘤的发病机制,评价药物疗效与给药方式有非常重要的意义。本文将目前对胶质瘤的治疗方法与动物模型的研究进行综述。