人参皂苷Rg1对H2O2诱导的HaCaT细胞氧化损伤保护作用研究

目的 观察人参皂苷Rg₁对H₂O₂诱导的HaCaT细胞氧化损伤保护作用,并探讨其机制。方法 体外培养HaCaT细胞, H₂O₂诱导细胞建立氧化应激损伤模型,分为空白组、H₂O₂损伤组、人参皂苷Rg₁保护组。细胞增殖与毒性检测试剂盒(CCK-8)检测细胞存活率,Hochest染色法检测细胞凋亡情况,活性氧检测试剂盒测定细胞活性氧(ROS)水平,Western blot检测细胞中caspase-3、caspase-6、caspase-8、GAPDH蛋白表达。结果 H₂O₂诱导HaCaT细胞半数抑制浓度为100 μg?mL^-1;与H₂O₂损伤组比较,5、10和15mg?L^-1人参皂苷Rg₁预处理后,HaCaT细胞存活率明显升高(P<0.05),细胞核皱缩损伤状态明显改善,细胞凋亡数量显著减少。同时,人参皂苷Rg₁预处理可显著降低HaCaT细胞ROS水平,下调凋亡相关标志蛋白-活化型caspase-3、caspase-6、caspase-8蛋白表达水平。结论 人参皂苷Rg₁对H₂O₂诱导的HaCaT细胞氧化应激损伤具有一定的保护作用,其机制可能与增强细胞清除自由基能力及抑制凋亡相关。     

藏药蕨麻对原代培养小鼠肝细胞酒精损伤保护作用研究

目的 研究藏药蕨麻对原代培养酒精损伤肝细胞的保护作用。方法 原代肝细胞经分离纯化培养后,MTT法评价藏药蕨麻对酒精损伤肝细胞存活率的影响;荧光染色法测定藏药蕨麻对酒精损伤肝细胞活性氧物质(ROS)含量、细胞内钙离子浓度的影响;流式细胞仪检测藏药蕨麻对酒精损伤肝细胞凋亡的影响;免疫印迹法检测藏药蕨麻对Bcl-2和Bax表达的影响。结果 经酒精损伤后,肝细胞存活率降低;细胞内ROS含量和钙离子浓度增高;凋亡抑制基因Bcl-2减弱、促凋亡基因Bax表达增强。藏药蕨麻可明显提高细胞存活率;降低细胞内ROS含量和钙离子浓度;改善凋亡情况,增强Bcl-2表达,抑制Bax表达,且作用呈剂量依赖性。结论 藏药蕨麻对原代培养小鼠肝细胞酒精损伤具有一定的保护作用。     

五味子乙素通过ROS介导内质网应激诱导人乳腺癌MDA-MB-231细胞凋亡的研究

目的 研究五味子乙素对人乳腺癌MDA-MB-231细胞凋亡的影响及其作用机制。方法 用细胞计数试剂(CCK-8)检测不同浓度五味子乙素对MDA-MB-231细胞存活率的影响;五味子乙素（10、20、40 μmol/L）作用 MDA-MB-231 细胞 24 h,分别用Annexin V-FITC/PI检测细胞凋亡情况;用DCFA-DA荧光探针检测细胞内活性氧（ROS）水平;用Western blot法检测细胞凋亡及内质网应激相关蛋白（Bcl-2、Bax、CHOP、GPR78、PERK、p-PERK、p-eIF2α、eIF2）的表达。结果 与空白组比较,随着五味子乙素浓度增大,细胞存活率明显降低,其IC₅₀为19.16 μmol/L;与对照组比较,五味子乙素（10、20、40 μmol/L）均能抑制细胞克隆形成(P<0.05),且呈剂量依赖;五味子乙素（10、20、40 μmol/L）均可诱导细胞凋亡（P<0.05）,使抗凋亡蛋白BCL-2的表达显著降低,促凋亡蛋白Bax的表达显著升高(P<0.05);五味子乙素（10、20、40 μmol/L）显著升高细胞内ROS水平(P<0.05),且呈剂量依赖;五味子乙素（10、20、40 μmol/L）能够激发内质网应激,使内质网应激相关蛋白CHOP、GPR78、p-eIF2α表达增多(P<0.05),且呈剂量依赖。结论 五味子乙素可能通过ROS介导内质网应激诱导MDA-MB-231细胞凋亡。     

常春卫矛提取物对 H2O2诱导的血管内皮细胞损伤的保护作用

摘 要 目的：研究常春卫矛乙醇、乙酸乙酯和正丁醇提取物分别对血管内皮细胞ECV 304氧化损伤的保护作用。方法: 体外培养ECV 304细胞,以H2O2诱导ECV 304细胞氧化损伤为模型,分别将常春卫矛乙醇、乙酸乙酯和正丁醇提取物（终浓度为400,200,100,50,25 μg·ml^-1）作用于细胞24 h后,以MTT法检测细胞存活率;Hochest染色观察细胞凋亡情况;以测定超氧化物歧化酶（SOD）、一氧化氮合酶（NOS）和一氧化氮（NO）的含量评价药物对血管内皮细胞氧化应激的影响。结果: 常春卫矛乙醇、乙酸乙酯和正丁醇提取物在25～400 μg·ml^-1 浓度范围内,对ECV 304细胞均无细胞毒作用,其中乙酸乙酯提取物在400 μg·ml^-1浓度下,对细胞有一定增殖作用（P<0.05）;常春卫矛乙酸乙酯（浓度50～400 μg·ml^-1）、正丁醇（浓度100～400 μg·ml^-1）提取物对氧化损伤ECV 304细胞存活率有显著提高,OD值与模型组比较,差异有统计学意义（P<0.05或P<0.01）。常春卫矛乙醇、乙酸乙酯和正丁醇提取物能明显提高氧化损伤ECV 304细胞分泌SOD、NO水平（P<0.05或P<0.01）,对NOS水平无影响;常春卫矛乙醇、乙酸乙酯、正丁醇提取物均能抑制氧化损伤细胞凋亡,细胞核形态改善,凋亡率与模型组比较差异有统计学意义（P<0.01）。结论:常春卫矛提取物对H2O2诱导血管内皮细胞氧化损伤有一定保护作用。     

丁香酚对H2O2诱导H9C2心肌细胞损伤的保护作用

目的 研究丁香酚对H₂O₂诱导H9C2心肌细胞损伤的影响。方法 使用不同浓度H₂O₂建立H9C2心肌细胞氧化损伤模型,将建立好的心肌细胞氧化损伤模型分为对照组、50 μg/mL丁香酚处理组、100 μg/mL丁香酚处理组和200 μg/mL丁香酚处理组,采用MTT法观察吸光度值（OD）变化来评价丁香酚对H9C2心肌细胞活力的影响;采用Hoechst染色法观察细胞核形态变化,评价丁香酚对H9C2心肌细胞凋亡的影响;为进一步研究丁香酚的抗氧化损伤作用,采用比色法检测试剂盒观察丁香酚对H9C2心肌细胞乳酸脱氢酶（LDH）、丙二醛（MDA）及超氧化物歧化酶（SOD）含量的影响。结果 400 μmol/L H₂O₂显著降低H9C2细胞活力,增加细胞凋亡,适宜建立H9C2心肌细胞氧化损伤模型。100 μg/mL和200 μg/mL的丁香酚增加H9C2细胞活力,减少细胞凋亡（P<0.05）;同时,H₂O₂诱导H9C2细胞LDH及MDA含量增加和SOD含量减少的效应也可被100 μg/mL和200 μg/mL的丁香酚抑制。结论 丁香酚对H₂O₂诱导H9C2心肌细胞损伤具有保护作用。     

五味子乙素调控小神经胶质BV-2细胞氧化应激损伤的机制研究

目的 研究五味子乙素对H₂O₂诱导小神经胶质BV-2细胞氧化应激损伤的保护作用,并探讨其可能的作用机制。方法 体外常规培养BV-2细胞,用H₂O₂诱导细胞氧化应激损伤模型,将细胞分为正常对照组、模型组、五味子乙素10,20,40 μmol·L^-1组。CCK8试剂盒检测五味子乙素对细胞存活率的影响,相关试剂盒检测细胞匀浆中MDA、NO含量及SOD活性,免疫印迹方法检测Jak2、p-Jak2、State3、p-State3、HO-1及SOD1蛋白表达水平。结果 与模型组相比,不同剂量的五味子乙素可明显增加细胞的存活率、降低氧化应激产物MDA及NO的释放、增强SOD酶活性,差异均有统计学意义（P<0.05）;免疫印迹结果显示五味子乙素可明显提高HO-1、SOD1蛋白水平,并抑制Jak2、State3的磷酸化水平,与模型组相比差异有统计学意义（P<0.05）。结论 五味子乙素可明显降低BV-2细胞的氧化应激损伤,其作用机制可能与抑制Jak2/State3信号通路的活化有关。     

扇贝多肽保护单次UVA氧化损伤HaCaT细胞

目的探讨扇贝多肽对单次长波紫外线辐射HaCaT角质形成细胞氧化损伤的保护作用机制。方法从栉孔扇贝中提取扇贝多肽(PCF,Mr=879)。UVA辐射强度为5J·cm-2。酶生化法测定胞质SOD,GSH-px活性,ROS、MDA水平;透射电镜观察细胞超微结构的改变;原位杂交技术检测细胞内p21mRNA的变化。结果在5J·cm-2UVA辐射下,在给定浓度范围内PCF能剂量依赖性降低胞质ROS、MDA水平;提高SOD,GSH-px活力;电镜下可见PCF可保护细胞超微结构;p21mRNA原位杂交发现PCF可明显抑制其表达。结论扇贝多肽对单次UVA诱导的人HaCaT细胞氧化损伤有保护作用。其机制与清除氧自由基、提高抗氧化酶活性、抑制p21mRNA表达及细胞凋亡有关。     

扇贝多肽保护单次UVA氧化损伤HaUaT细胞

目的探讨扇贝多肽对单次长波紫外线辐射HaCaT角质形成细胞氧化损伤的保护作用机制。方法从栉孔扇贝中提取扇贝多肽(PCF,Mr=879)。UVA辐射强度为5J·cm-2。酶生化法测定胞质SOD,GSH-px活性,ROS、MDA水平;透射电镜观察细胞超微结构的改变;原位杂交技术检测细胞内p21mRNA的变化。结果在5J·cm-2UVA辐射下,在给定浓度范围内PCF能剂量依赖性降低胞质ROS、MDA水平;提高SOD,GSH-px活力;电镜下可见PCF可保护细胞超微结构;p21mRNA原位杂交发现PCF可明显抑制其表达。结论扇贝多肽对单次UVA诱导的人HaCaT细胞氧化损伤有保护作用。其机制与清除氧自由基、提高抗氧化酶活性、抑制p21mRNA表达及细胞凋亡有关。     

柿叶提取物对氧化应激损伤U257神经胶质细胞的保护作用

目的研究中成药“柿叶提取物”对体外过氧化氢（H2O2）引起U257神经胶质细胞氧化应激损伤的保护作用及其保护机制。方法体外培养U257神经胶质细胞,建立氧化应激引起的细胞损伤模型;采用MTr比色法测定细胞的存活率;以Hoechst33258荧光染色法检测细胞凋亡;用丙二醛（MDA）及还原型谷胱甘肽（GSH）测定试剂盒作相应酶活性或产物含量分析。结果U257神经胶质细胞与300μmol／L的H2O2共孵育10h可诱导细胞凋亡。柿叶提取物（5、10、30μg／ml）3个剂量组均能降低凋亡细胞百分率,降低细胞内MDA含量,提高细胞内GSH含量,该作用呈剂量依赖性。结论柿叶提取物片对氧化应激引起的U257神经胶质细胞损伤有明显的保护作用,其保护机制与细胞内氧化还原的平衡状态改善有关。     

圣草次苷激活Nrf2信号通路保护H9c2心肌细胞缺氧复氧损伤作用研究

目的 建立大鼠H9c2心肌细胞缺氧/复氧（H/R）损伤模型,考察圣草次苷改善心肌缺血再灌注损伤的作用机制。方法 利用无糖无血清培养基结合厌氧（94%N₂、5%CO₂、1%O₂）处理H9c2心肌细胞4h后,更换新鲜完全培养基再放入正常孵箱复氧24h,制备H/R损伤模型。在造模前12h给予圣草次苷（5、10、20μg·mL^-1）,细胞活力及乳酸脱氢酶（LDH）检测实验中选择灯盏乙素（20μg·mL^-1）作为阳性药,对照组及模型组给予等体积DMSO。MTT法测定细胞存活率;试剂盒检测细胞培养上清液中LDH水平;试剂盒检测细胞内丙二醛（MDA）水平和超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、谷胱甘肽过氧化物酶（GSH-Px）活力;TUNEL染色检测细胞凋亡;DCFH-DA和JC-1探针分别检测细胞内活性氧（ROS）和线粒体膜电位改变;Western blotting检测核蛋白中转录因子（NF）-E2相关因子2（Nrf2）和总蛋白中血红素氧合酶1（HO-1）、γ-谷氨酰半胱氨酸连接酶（GCL）水平。结果 与对照组比较,H/R损伤诱导的模型组细胞存活率明显下降,凋亡明显增加,LDH水平明显升高,细胞内MDA水平明显升高,SOD、CAT、GSH-Px活力明显降低,ROS释放明显增多,线粒体膜电位明显降低,差异均有统计学意义（P＜0.01）;与模型组比较,圣草次苷可剂量相关性地改善上述变化,其中10、20μg·mL^-1组均差异显著（P＜0.01）。Western blotting结果显示,与对照组比较,模型组细胞Nrf2核转位以及HO-1、GCL表达水平无显著变化;与模型组比较,圣草次苷10、20μg·mL^-1显著增加Nrf2核转位及HO-1、GCL表达水平（P＜0.01）。结论 圣草次苷能够保护H/R诱导的H9c2心肌细胞损伤,其可能通过激活Nrf2抗氧化信号通路,增加细胞内源性抗氧化能力,抑制氧化应激损伤,保护线粒体功能以阻止细胞凋亡的发生。     

五味子提取物对小鼠银屑病样皮损的抑制作用及机制研究

目的 探讨五味子提取物对小鼠银屑病样皮损的抑制作用及机制。方法 使用咪喹莫特乳剂建立小鼠银屑病背部皮损模型,将小鼠分为对照组、模型组、他克莫司5 mg/kg组以及五味子提取物0.05、0.25 mg/kg组,并于造模后在小鼠背部皮肤涂抹相应药物。取小鼠背部皮肤组织,分析皮损症状,对其进行苏木精–伊红（HE）染色,并观察测定表皮厚度。免疫组织化学测定淋巴细胞表面分子（CD-8）、环氧化酶-2(COX-2)、细胞外调节蛋白激酶（ERK）、磷酸化细胞外调节蛋白激酶（p-ERK）的表达情况。建立3D皮肤模型,使用双氧水造模后,噻唑蓝（MTT）检测五味子提取物抗氧化修复活性、酶联免疫吸附法检测皮肤模型组织中超氧化物歧化酶（SOD）和过氧化氢酶（CAT）的酶活力和炎症因子白细胞介素-6(IL-6)的含量。结果 五味子提取物可以缓解由咪喹莫特乳剂诱导的小鼠银屑病皮肤损伤、红斑、炎症,改善其皮损处组织细胞情况,降低银屑病模型小鼠表皮厚度（P<0.05）;五味子提取物可以下调银屑病模型小鼠皮肤组织中COX-2、ERK、pERK、CD-8的表达（P<0.05、0.01）;3D皮肤模型检测结果显...     

Protective effects of Belamcandae Rhizoma against skin damage by ameliorating ultraviolet‐B‐induced apoptosis and collagen degradation in keratinocytes

Ultraviolet‐B light (UV‐B) is a major cause of skin photoaging, inducing cell death and extracellular matrix collapse by generating reactive oxygen species (ROS). Belamcandae Rhizoma (BR), the rhizome of Belamcanda chinensis Leman, exhibits antioxidant properties, but it remains unknown whether BR extract ameliorates UV‐B‐induced skin damage. In this study, we evaluated the effects of a standardized BR extract on UV‐B‐induced apoptosis and collagen degradation in HaCaT cells. BR was extracted using four different methods. We used radical‐scavenging assays to compare the antioxidative activities of the four extracts. Cells were irradiated with UV‐B and treated with BR boiled in 70% (vol/vol) ethanol (BBE). We measured cell viability, intracellular ROS levels, the expression levels of antioxidative enzymes, and apoptosis‐related and collagen degradation‐related proteins. The irisflorentin and tectorigenin levels were measured via high‐performance liquid chromatography. BBE exhibited the best radical‐scavenging and cell protective effects of the four BR extracts. BBE inhibited intracellular ROS generation and induced the synthesis of antioxidative enzymes such as catalase and glutathione. BBE attenuated apoptosis by reducing the level of caspase‐3 and increasing the Bcl‐2/Bax ratio. BBE reduced the level of matrix metalloproteinase‐1 and increased that of type I collagen. The irisflorentin and tectorigenin contents were 0.23% and 0.015%, respectively. From these results, BBE ameliorated UV‐B‐induced apoptosis and collagen degradation by enhancing the expression of antioxidative enzymes. It may be a useful treatment for UV‐B‐induced skin damage.     

Gingko biloba leaf extract induces oxidative stress in carcinoma HSC-2 cells

The antiproliferative effects of a Gingko biloba leaf extract to cells from tissues of the human oral cavity were studied. Toxicity to carcinoma HSC-2 cells was correlated with the prooxidative nature of the extract. G. biloba leaf extract generated reactive oxygen species (ROS) in cell culture medium and, albeit to a lesser extent, in buffer, with higher levels detected at alkaline pH. Lowered levels of ROS were detected in culture medium coamended with the extract and with either catalase or superoxide dismutase, indicating the generation of hydrogen peroxide and superoxide anion, respectively. Biological activity of the extract was through oxidative stress. Toxicity to the HSC-2 cells was lessened by the ROS scavengers, divalent cobalt and pyruvate, by catalase, and by the antioxidant, N-acetyl-l-cysteine, and was potentiated by the glutathione depleters, dl-buthionine-[S,R]-sulfoximine, 1-chloro-2,4-dinitrobenzene, and bis(2-chloroethyl)-N-nitrosourea. G. biloba reacted directly with authentic glutathione and lowered the intracellular glutathione content in HSC-2 cells. Induction of apoptosis upon exposure of HSC-2 cells to G. biloba extract was noted by apoptotic cell morphologies, by TUNEL staining, and by PARP cleavage. The data strongly suggest that the prooxidative nature of the G. biloba extract was the cause of apoptotic cell death.     

泽漆抑制三阴乳腺癌MDA-MB-231细胞及其凋亡机制研究

目的 研究泽漆对三阴乳腺癌MDA-MB-231细胞的作用及其作用机制。方法 用MTT法检测细胞活力;用荧光显微镜法测定MDA-MB-231细胞的活性氧（ROS）生成量;用流式细胞仪检测细胞的凋亡率;用TUNEL检测法检测细胞凋亡DNA碎片;用Western blot检测caspase-9、caspase-3、PARP等凋亡相关因子的水平变化。结果 MTT试验显示泽漆提取物对MDA-MB-231细胞具有显著的抑制作用,但作用可被ROS抑制剂NAC及caspase抑制剂Z-VAD-FMK所消除;荧光显微镜检测显示泽漆提取物能显著提高ROS的生成;流式细胞仪检测显示泽漆提取物处理后,PI染色阳性细胞明显增加,但被NAC减弱。Caspase-9、caspase-3在提取物处理后均转为激活形式,PARP被剪切。TUNEL法显示,提取物处理后细胞凋亡碎片明显增多,而提前加入ROS抑制剂NAC和caspase抑制剂Z-VAD-FMK能使泽漆提取物诱导凋亡的DNA碎片明显减少。结论 泽漆乙酸乙酯提取物可以有效抑制MDA-MB-231细胞的生长,诱导其凋亡,其作用机制可能与ROS过量生成所致的线粒体损伤途径有关。     

Pro-oxidant status and Nrf2 levels in psoriasis vulgaris skin tissues and dimethyl fumarate-treated HaCaT cells

Reactive oxygen species (ROS) contribute to pathogenesis of many inflammatory skin diseases, including psoriasis. The aim of this study is to compare antioxidant protein expression in psoriasis vulgaris (PV) skin tissues with that in normal skin tissues in vivo and to evaluate the effects of dimethyl fumarate (DMF), used for the treatment of psoriasis, on ROS generation and apoptosis in a human keratinocyte cell line HaCaT. Compared with normal skin tissues, PV skin tissues showed increased protein oxidation as well as down-regulation of Nrf2 and its regulatory proteins such as HO-1 and AKR1C3. Using HaCaT cells to model DMF-induced pro-oxidant effects in the skin cells, we found that DMF treatment induced increased ROS levels and apoptotic cell death, as signified by increased proportion of cells with Annexin V-PE(+) staining and a sub-G₀/G₁ peak in the cell cycle. Preceding these changes, DMF treatment resulted in up-regulation of Nrf2, HO-1, and AKR1C3 proteins in these cells. Collectively, increased oxidative stress and impaired cellular anti-oxidant enzyme systems may participate in the pathogenesis of PV. DMF may exert an additive therapeutic efficacy in PV by attenuating the redox burden and subsequent oxidative damage to normal keratinocytes through activation of Nrf2 pathway relative to PV.     

Elevated levels of DNA repair enzymes and antioxidative enzymes by (+)-catechin in murine microglia cells after oxidative stress

(+)-Catechin possesses a broad range of pharmacological properties, including antioxidative effect. However, little is reported on the mechanism by which (+)-catechin protects microglia cells from DNA damage by oxidative stress. In this study, TUNEL assay and DNA electrophorysis indicated that (+)-catechin markedly blocked DNA fragmentation and apoptosis of microglia cells by tBHP exposure. A potent antioxidative effect of (+)-catechin was confirmed by comparison with a putative antioxidant agent, N-acetylcysteine at the lower doses. Furthermore, the increased intracellular ROS by tBHP exposure were scavenged by elevated activities of catalase (CAT) and superoxide dismutase (SOD) after (+)-catechin treament. (+)-Catechin partially inhibited the activation of caspase-3, thereby both cleavage of poly (ADP-ribose) polymerase (PARP) and degradation of inhibitor of caspase-activated DNase (ICAD) were effectively abolished. In addition, the expression of PARP for repair of impaired DNA was significantly increased by (+)-catechin treatment. Taken together, these data suggest that protective effects of (+)-catechin against oxidative DNA damage of microglia cells is exerted by the increased expression of DNA repair enzyme PARP and antioxidant enzyme activities.     

Skin delivery of epigallocatechin-3-gallate (EGCG) and hyaluronic acid loaded nano-transfersomes for antioxidant and anti-aging effects in UV radiation induced skin damage

The present work attempts to develop and statistically optimize transfersomes containing EGCG and hyaluronic acid to synergize the UV radiation-protective ability of both compounds, along with imparting antioxidant and anti-aging effects. Transfersomes were prepared by thin film hydration technique, using soy phosphatidylcholine and sodium cholate, combined with high-pressure homogenization. They were characterized with respect to size, polydispersity index, zeta potential, morphology, entrapment efficiency, Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), in vitro antioxidant activity and ex vivo skin permeation studies. Cell viability, lipid peroxidation, intracellular ROS levels and expression of MMPs (2 and 9) were determined in human keratinocyte cell lines (HaCaT). The composition of the transfersomes was statistically optimized by Design of Experiments using Box–Behnken design with four factors at three levels. The optimized transfersome formulation showed vesicle size, polydispersity index and zeta potential of 101.2?±?6.0?nm, 0.245?±?0.069 and ?44.8?±?5.24?mV, respectively. FTIR and DSC showed no interaction between EGCG and the selected excipients. XRD results revealed no form conversion of EGCG in its transfersomal form. The optimized transfersomes were found to increase the cell viability and reduce the lipid peroxidation, intracellular ROS and expression of MMPs in HaCaT cells. The optimized transfersomal formulation of EGCG and HA exhibited considerably higher skin permeation and deposition of EGCG than that observed with plain EGCG. The results underline the potential application of the developed transfersomes in sunscreen cream/lotions for improvement of UV radiation-protection along with deriving antioxidant and anti-aging effects.     

Curcumin protects mitochondria from oxidative damage and attenuates apoptosis in cortical neurons

AIM: To investigate the effect of curcumin on tert-butyl hydroperoxide (t-BHP)-induced oxidative damage in rat cortical neurons and to explore the possible mechanism. METHODS: Primary cultured rat cortical neurons wereperformed in vitro and cell viability was measured by MTT assay. DNA fragmentation was used to evaluate cellapoptosis. Intracellular reactive oxygen species (ROS) and mitochondrial membrane potential (Aψm) was determined by flow cytometric assay. Cellular glutathione (GSH) content was measured by spectrophotometer.‘ Bcl-2family proteins, cytochrome c, cleaved caspase-3, and poly (ADP-ribose) polymerase (PARP) were detected byWestern blot. RESULTS: Exposure of tBHP 100 μmol/L to neurons for 60 rain resulted in △ψm loss and cyto-chrome c release from mitochondria and subsequent activation of caspase-3 and PARP cleavation, and cell apoptosis.After removal of tBHP and then further treatment with curcumin (2.5-20 μmol/L) for 18 h, curcumin abrogated △ψm loss and cytochrome c release, blocked activation of caspase 3, and altered the expression of Bcl-2 family.Further curcumin treatment also prevented cellular GSH and decreased intracellular ROS generation markedly.Curcumin eventually attenuated tBHP-induced apoptosis in cortical neurons. CONCLUSION: Curcumin mayattenuate oxidative damages in cortical neurons by reducing intracellular production of ROS and protecting mito-chondria from oxidative damage.     

Eckol inhibits ultraviolet B-induced cell damage in human keratinocytes via a decrease in oxidative stress

In previous reports, the antioxidant effects of eckol were shown to protect cells against hydrogen peroxide- and gamma ray-induced oxidative stress. In this study, the role of eckol in protecting human skin keratinocytes (HaCaT) against UVB-induced oxidative cell damage was investigated. Also, triphlorethol-A, one of the chemical components in Ecklonia cava, and quercetin a well known antioxidant, were compared with eckol in terms of antioxidant activity based on chemical structure. Eckol decreased UVB-induced intracellular reactive oxygen species (ROS), decreased injury to cellular components resulting from UVB-induced oxidative stress, and restored cell viability. In addition, eckol reduced UVB-induced apoptosis by inhibiting the disruption of mitochondrial membranes. These results suggest that eckol protects human keratinocytes against UVB-induced oxidative stress by scavenging ROS, thereby lessening injury to cellular components.     

Effect of a Lignan-Enriched Extract of Schisandra Chinensis on Aflatoxin B1 and Cadmium Chloride-Induced Hepatotoxicity in Rats

Abstract: Treatment of rats with a lignan-enriched extract of the fruit of Schisandra chinensis could enhance hepatic antioxidant/detoxification system, as indicated by increases in hepatic reduced glutathione (GSH) level as well as hepatic glutathione reductase and glutathione S-transferase activities. The hepatoprotective action was evident after aflatoxin β₁ or cadmium chloride (Cd) challenge. Schisandra chinensis pretreatment protected against aflatoxin B₁ or Cd-induced hepatocellular damage in rats. However, pretreating rats with α-tocopherol acetate (vitamin E) did not protect against hepatic damage induced by both toxins. Results from the present as well as our previous studies demonstrate that the hepatoprotection afforded by Schisandra chiensis pretreatment is not hepatotoxin specific. Schisandra chinensis seems to be more effective than vitamin E in protecting against aflatoxin B₁ and Cd toxicity. The mechanism of hepatoprotection afforded by Schisandra chinensis pretreatment may involve facilitation of both antioxidant and detoxification processes in the liver.