五味子酚和丹酚酸A抗氧化作用机理及对阿霉素心脏毒性的保护作用

阿霉素是一种广谱有效的抗肿瘤药,它的发现曾被认为是肿瘤治疗史上的里程碑;但长期使用阿霉素可产生严重的副作用——心脏毒性,这限制了其临床使用,因此降低阿霉素的心脏毒性,保持阿霉素的抗肿瘤活性,是国内外目前正在研究的一个重要课题。已知阿霉素的抗肿瘤作用是通过损伤细胞DNA,而其心脏毒性则是因其在心脏产生自由基所致。     

丹酚酸A对大鼠脑缺血/再灌注损伤及抗氧化酶活性的影响

目的：探讨丹酚酸A对大鼠脑缺血/再灌注（cerebral ischemia/reperfusion,CI/R）损伤及抗氧化酶活性的影响。方法：采用大鼠脑中动脉闭塞（middle cerebral arteryocclusion,MCAO）2 h再灌注24 h模型。实验终末,检测脑梗死面积,脑水肿以及评价神经功能损伤,并进一步分析脑组织中三种抗氧化酶的活性水平。结果：与模型组相比,丹酚酸A组大鼠脑梗死面积显著减少（P〈0.05）,水肿程度显著减轻（P〈0.05）,神经功能学评分显著下降（P〈0.05）。模型组再灌注24 h后,SOD,GSH-PX及CAT活性显著下降（P〈0.05）;丹酚酸A组SOD,GSH-PX及CAT活性则显著升高（P〈0.05）。结论：丹酚酸A对大鼠CI/R损伤具有保护作用,可能与CI/R损伤时的脑组织SOD,GSH-PX及CAT活性显著升高相关。     

丹酚酸A对大鼠脑缺血/再灌注损伤及抗氧化酶活性的影响

目的:探讨丹酚酸A对大鼠脑缺血/再灌注(cerebral ischemia/reperfusion,CI/R)损伤及抗氧化酶活性的影响。方法:采用大鼠脑中动脉闭塞(middle cerebral arteryocclusion,MCAO)2 h再灌注24 h模型。实验终末,检测脑梗死面积,脑水肿以及评价神经功能损伤,并进一步分析脑组织中三种抗氧化酶的活性水平。结果:与模型组相比,丹酚酸A组大鼠脑梗死面积显著减少(P0.05),水肿程度显著减轻(P0.05),神经功能学评分显著下降(P0.05)。模型组再灌注24 h后,SOD,GSH-PX及CAT活性显著下降(P0.05);丹酚酸A组SOD,GSH-PX及CAT活性则显著升高(P0.05)。结论:丹酚酸A对大鼠CI/R损伤具有保护作用,可能与CI/R损伤时的脑组织SOD,GSH-PX及CAT活性显著升高相关。     

五味子酚等三种抗氧化剂对氧化应激损伤中枢神经细胞的保护作用及其作用机

氧化应有激（ｏｘｉｄａｔｉｖｅ ｓｔｒｅｓｓ）在中区神经系统退行性疾病,如帕金森氏病、老年性痴呆和多发性硬化等的发病机制中起重要作用。这些疾病严重影响着老年人的生活质量,因此寻找有效的抗氧化剂用于防治中枢神经系统退行性疾病的发生和发展是一个十分重要的迫切的问题。本文研究了五味子酚（Ｓａｌ）、丹酚酸Ａ（ＳａｌＡ）和ＳＹ－Ｌ三种化合物对氧化应激损伤中枢神经的保护作用及其作用机理。Ｓａｌ和ＳａｌＡ分别为     

知母宁(Chinonin)对阿霉素的减毒增效作用

采用阿霉素林外损伤大鼠心脏线粒体模型,研究天然抗氧化剂知母宁对阿霉素毒性及抗肿瘤活性的影响。结果表明：阿霉素体外引起大鼠心脏线粒体丙二醛（ＭＤＡ）生成、ＡＴＰ酶活性丧失及膜流动性降低等,知母宁对上述毒性损伤均有明显的保护作用;ＭＴＴ法检测发现,知母宁对阿霉素的抗肿瘤活性无明显影响,这说明知母宁拮抗阿霉素引起的心脏毒性但不影响其抗肿瘤活性,这对临床应用知母宁以减轻阿霉素毒副的可能性提供了实验依据。     

还原型谷胱甘肽对阿霉素致大鼠心脏毒性的保护作用及其机制

目的:探讨还原型谷胱甘肽(GSH)对阿霉素所致大鼠心脏毒性的保护作用及其机制。方法:选取40只健康SD大鼠作为实验动物,将其随机分为4组,即GSH(小剂量)组+阿霉素组(小剂量组)、GSH(大剂量)+阿霉素组(大剂量组)、阿霉素组及生理盐水组,每组各10只。上述前3组均给予阿霉素;小剂量组给予GSH 250 mg/kg;大剂量组给予GSH 500 mg/kg;生理盐水组给予相同体积的生理盐水。末次给药24 h后,应用免疫组化学SP法检测大鼠心肌组织中BAX和BCL-2蛋白的表达情况,应用ELISA法测定大鼠血清中CK(肌酸激酶)、CK-MB(肌酸激酶同工酶)、LDH(乳酸脱氢酶)的含量以及心肌组织中超氧化物歧化酶(SOD)、丙二醛(MDA)的活性,并对实验数据进行统计学分析。结果:1与阿霉素组相比,应用GSH干预的大鼠心肌组织中BCL-2的表达显著升高,BAX的表达显著降低,差异均有统计学意义(P0.05);大、小剂量组间BAX和BCL-2蛋白的表达水平比较无统计学差异(P0.05);2与阿霉素组相比,GSH干预的大鼠血清CK、CK-MB、LDH水平均显著下降,但大、小剂量组间比较无显著性差异(P0.05);3与阿霉素组相比,应用GSH干预的大鼠心肌组织MDA水平降低,SOD活力升高(P0.05),但大、小剂量组间比较无显著性差异(P0.05)。结论:还原型谷胱甘肽能够抑制阿霉素导致的心脏毒性作用,其作用机制可能与提高心肌组织BCL-2蛋白的表达与SOD水平、降低MDA水平以及BAX蛋白的表达有关。     

丹酚酸B对大鼠离体工作心脏血流动力学的影响

目的 研究丹酚酸B对离体大鼠工作心脏血流动力学的影响.方法 采用Langendorff离体心脏灌流的方法,以左室内压( LVSP)、左室舒末压(LVEDP)、室内压最大上升速率(+dp/dtmax)、室内压最大下降速率(- dp/dtmax)、心率(HR)等血流动力学参数为指标,观察丹酚酸B对心肌收缩性能的影响.结果 不同剂量(10、5、2.5 mg/L)的丹酚酸B可使LVSP、±dp/dtmax明显升高,同时使HR减慢,并呈剂量依赖性,但对LVEDP无明显作用.结论 丹酚酸B对离体工作心脏有剂量依赖性正性肌力作用.     

棉籽糖低钾右旋糖酐液中灌注丹酚酸B对大鼠离体肺的保护作用

目的:研究丹酚酸B对离体供肺的保护作用。方法:将SD大鼠36只,随机分为对照组、低浓度实验组和高浓度实验组,每组各12只。对照组选择棉籽糖低钾右旋糖酐液(R-LPD液),实验组在对照组灌注液的基础上分别加入丹酚酸B注射液800mg/L、1200 mg/L。呼吸机辅助通气下边灌注边取下供肺,离体后再用灌注液行顺灌及逆灌,后放入盛有4℃相应保存液的无菌冰桶内保存。术后6 h、9 h、12 h、24 h分别测两组供肺的湿干重比(W/D)、髓过氧化物酶(MPO)活性、丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性。结果:各组内12 h前相邻时间点比较,各参数均无统计学差异(P0.05);24 h后各参数明显高于12 h(P0.01)。各组间同一时间点比较,12 h前组间各参数无统计学差异(P0,05);保存至24 h,W/D、MDA含量、MPO活性比较,对照组低浓度实验组高浓度实验组(P0.05);而SOD活性比较,对照组低浓度实验组高浓度实验组(P0.05)。光镜下各肺组织保存至12 h以前,病理形态学均无明显炎症损伤,仅表现轻度炎症反应。12 h后对照组组光镜病理观察出现肺泡结构破坏、间质水肿、炎症损伤较低浓度实验组组明显,高浓度实验组情况较低浓度实验组肺组织结构更为清晰且炎症损伤较轻。结论:加入丹酚酸B后的灌注液在12 h前未有明显优势,12 h后能更加有效地保证小鼠供肺质量,使供体肺在离体情况下有效保存更长的时间,且高浓度丹酚酸B能更有效的提高对供体肺的保护发挥了重要作用。     

抗氧化剂丹酚酸A对缺氧鼠肺内动脉ACh舒张反应的影响

应用微量生物测定法观察了丹酚酸A(salvinolic acid A,Sal.A)对慢性缺氧(5000m,10d)大鼠(200～300g)肺内动脉ACh舒张反应的影响,并对其机制进行了初步探讨。实验发现,慢性缺氧可明显减弱大鼠肺内动脉ACh(10~(-8)～10~(-4)mol/L)舒张反应(P<0.01～0.001),在浴槽内先加入Sal.A(10~(-4)mol/L),缺氧鼠肺内动脉ACh舒张反应明显增强(P<0.01),而在浴槽内同时加入血管内皮舒张因子(EDRF)灭活剂phenidon(5×10~(-5)mol/L),则Sal.A上述增强缺氧鼠肺内动脉ACh舒张反应的作用消失。此外,本实验还发现,在以黄嘌呤(X,10~(-4)mol/ L)-黄嘌呤氧化酶(XO,0.01U/ml)系统产生氧自由基损伤正常大鼠肺内动脉ACh舒张反应的基础上,Sal.A(10~(-4)mol/L)同样可明显减弱氧自由基对大鼠肺内动脉ACh舒张反应的损伤作用。结果表明,Sal.A可消除氧自由基对肺血管内皮细胞释放的EDRF的破坏作用而具有保护慢性缺氧鼠肺内动脉ACh舒张反应的作用。     

A new mechanism of action of vasopressin on the neuronal membrane]

It is shown in this work that vasopressin at the concentrations of 1 x 10(-16) to 1 x 10(-6) mol/l decreased statistically significant the amplitude of the electrosensitive sodium and calcium ionic currents of the mollusc's Lymnaea stagnalis neuronal membrane. This peptide increased the amplitude of the fast potassium current at the concentration of 1 x 10(-16) and 1 x 10(-15) mol/l. It decreased the fast potassium current and did not change the slow potassium current at the concentrations more than 1 x 10(-9) mol/l.     

Antifungal effects and mechanism of action of viscotoxin A3

Viscotoxins are cationic proteins, isolated from different mistletoe species, that belong to the group of thionins, a group of basic cysteine-rich peptides of approximately 5 kDa. They have been shown to be cytotoxic to different types of cell, including animal, bacterial and fungal. The aim of this study was to obtain information on the cell targets and the mechanism of action of viscotoxin isoform A3 (VtA3). We describe a detailed study of viscotoxin interaction with fungal-derived model membranes, its location inside spores of Fusarium solani, as well as their induced spore death. We show that VtA3 induces the appearance of ion-channel-like activity, the generation of H2O2, and an increase in cytoplasmic free Ca2+. Moreover, we show that Ca2+ is involved in VtA3-induced spore death and increased H2O2 concentration. The data presented here strongly support the notion that the antifungal activity of VtA3 is due to membrane binding and channel formation, leading to destabilization and disruption of the plasma membrane, thereby supporting a direct role for viscotoxins in the plant defence mechanism.     

Corosolic acid and its structural analogs: A systematic review of their biological activities and underlying mechanism of action

BackgroundThe corosolic acid (CA), also known as plant insulin, is a pentacyclic triterpenoid extracted from plants such as Lagerstroemia speciosa. It has been shown to have anti-diabetic, anti-inflammatory and anti-tumor effects. Its structural analogs ursolic acid (UA), oleanolic acid (OA), maslinic acid (MA), asiatic acid (AA) and betulinic acid (BA) display similar individual pharmacological activities to those of CA. However, there is no systematic review documenting pharmacological activities of CA and its structural analogues. This study aims to fill this gap in literature.PurposeThis systematic review aims to summarize the medical applications of CA and its analogues.MethodsA systematic review summarizes and compares the extraction techniques, pharmacokinetic parameters, and pharmacological effects of CA and its structural analogs. Hypoglycemic effect is one of the key inclusion criteria for searching Web of Science, PubMed, Embase and Cochrane databases up to October 2020 without language restrictions. ‘corosolic acid’, ‘ursolic acid’, ‘oleanolic acid’, ‘maslinic acid’, ‘asiatic acid’, ‘betulinic acid’, ‘extraction’, ‘pharmacokinetic’, ‘pharmacological’ were used to extract relevant literature. The PRISMA guidelines were followed.ResultsAt the end of the searching process, 140 articles were selected for the systematic review. Information of CA and five of its structural analogs including UA, OA, MA, AA and BA were included in this review. CA and its structural analogs are pentacyclic triterpenes extracted from plants and they have low solubilities in water due to their rigid scaffold and hydrophobic properties. The introduction of water-soluble groups such as sugar or amino groups could increase the solubility of CA and its structural analogs. Their biological activities and underlying mechanism of action are reviewed and compared.ConclusionCA and its structural analogs UA, OA, MA, AA and BA are demonstrated to show activities in lowering blood sugar, anti-inflammation and anti-tumor. Their oral absorption and bioavailability can be improved through structural modification and formulation design. CA and its structural analogs are promising natural product-based lead compounds for further development and mechanistic studies.