海蜇胶原蛋白肽的降血脂及抗氧化作用的研究

本研究以海蜇胶原蛋白为原料,经酶解得到海蜇胶原蛋白肽,探讨海蜇胶原蛋白肽对小鼠血脂的影响及抗氧化作用。以高脂饲料喂养ICR小鼠,建立高脂血症模型,研究胶原蛋白肽对小鼠肝系数和脂肪系数的变化情况及小鼠血脂水平、肝组织抗氧化功能的影响。结果表明海蜇胶原蛋白肽能显著降低小鼠肝系数和脂肪系数,能显著降低高脂血症小鼠血清总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)、动脉硬化指数(LDL-C/HDL-C)水平,升高高密度脂蛋白胆固醇(HDL-C)和抗动脉粥样硬化因子(HDL-C/TC);能提高肝组织超氧化物歧化酶(SOD)谷胱甘肽过氧化物酶(GSH-Px)的活力,并能减低丙二醛(MDA)的含量。海蜇胶原蛋白肽具有辅助减低血脂水平和增强抗氧化功能的作用。     

米糠蛋白抗氧化活性肽的制备

以水解度(DH％)和对DPPH自由基清除率为指标,筛选出制备米糠蛋白抗氧化活性肽的最适蛋白酶.研究最适蛋白酶的酶解条件,探讨底物浓度、蛋白酶的加入量、pH值、酶解时间等因素对水解度(DH％)和DPPH自由基清除率的影响;在单因素基础上采用Box-Behnken响应曲面中心组合设计法,对酶解米糠蛋白的工艺进行优化.试验结果表明,在加酶量13970.82 U/g,时间3.05h,底物浓度4.97％的水解条件下,米糠蛋白的水解度能够达到23.67％,活性肽对DPPH自由基清除率达到64.26％.     

猪皮胶原蛋白水解产物中的抗氧化活性肽的分离及其氨基酸组分

利用不同蛋白酶水解猪皮胶原蛋白,根据水解产物对自由基的清除率,筛选最适蛋白酶的组合,筛选抗氧化活性较高的肽类,并进行氨基酸分析.结果表明:胃蛋白酶→木瓜蛋白酶→菠萝蛋白酶为酶解胶原蛋白的最佳组合;分离纯化得到了三种具有较高抗氧化活性的肽;氨基酸组分分析显示:P1′、P2′和P3′组分具有自由基清除作用的关键氨基酸甲硫氨酸、酪氨酸和组氨酸等.     

马鹿茸血免疫活性肽的制备及其活性研究

本文以免疫活性和DPPH·的清除能力为指标,研究了用木瓜蛋白酶与中性蛋白酶水解马鹿茸血制备活性肽的条件,并初步探讨了此活性肽的免疫活性与对DPPH·清除能力之间的关系.实验结果表明:当[E/S]为9000 U/g时,中性蛋白酶和木瓜蛋白酶的水解温度各为50和45 ℃,pH各为7.1和6.8,分别水解2和1.5 h可以获得最佳的酶解效果.在相同蛋白含量的情况下,两酶复合水解物的淋巴细胞增殖率比单酶水解增加了20.8%.免疫活性与DPPH·清除能力之间存在一定的相关性(r=0.957,P<0.01).     

茶叶多糖的抗氧化活性研究

从婺源粗老绿茶叶中提取纯化出了茶叶多糖,研究了它对超氧自由基、DPPH自由基的清除作用,以及对β-胡萝卜素-亚油酸氧化体系的抑制作用,以此来评价该多糖的抗氧化活性.结果表明,茶叶多糖对超氧自由基、DPPH自由基有较好的清除作用,而对β-胡萝卜素-亚油酸氧化体系也有较明显的抑制作用.     

功能性抗氧化肽制备与机制研究进展

抗氧化肽作为食品和机体的抗氧化剂具有广阔应用前景,通过酶水解蛋白质能得到天然抗氧化肽.本文对水解蛋白来源抗氧化肽的制备和抗氧化机制进行了综述.     

金属螯合肽分离纯化及其抗氧化活性的研究进展

综述了金属螯合肽的来源、分离纯化及构效关系,分析了金属螯合肽抗氧化活性的相关研究进展,并展望了金属螯合肽的发展前景。     

见血封喉乳汁脂溶性成分及其抗氧化活性研究

首次采用气相色谱.质谱联用技术(GC-MS)对见血封喉(Antiaris toxicaria(Pers.)Lesch.)乳汁的脂溶性成分进行了分析,共鉴定了27个化学成分,占其总量的91.7%.用清除DPPH自由基能力的方法测定了见血封喉乳汁脂溶性部位的抗氧化活性,结果显示出一定的抗氧化活性,SC50值为500μg ml-1.     

黑豆多肽分离及其抗氧化活性的研究

采用凝胶柱层析法分离具有抗氧化活性的黑豆多肽,并分析其分子量分布;同时还采用DPPH·清除法研究各分离肽段的抗氧化活性,对抗氧化活性最佳的肽段进行动力学分析.结果表明:黑豆多肽经分离后得到3个片段,黑豆小分子肽BSP3对DPPH·自由基具有最强清除作用,其半清除浓度(HSC50)为0.664 mg/mL.所以,分子量小于1000 Da的黑豆小分子肽具有很好的抗氧化活性.     

纳豆中抗氧化肽的分离纯化与活性研究

从发酵的纳豆中提取具有抗氧化活性的多肽,通过分子筛层析和反相高效液相色谱对纳豆上清液进行分离纯化,并采用电喷雾串联质谱进行结构鉴定.结果表明:纳豆发酵后的蛋白(多肽)混合物经Sephadex G-50凝胶色谱进行分离纯化后得到3个组分(F1、F2和F3),其中组分F3的抗氧化活性最强,总还原力达到(8.4±0.6)mm...     

三种常见品牌护肤品暴露对鲮肝脏SOD和GST活性、GSH含量的影响

研究护肤品暴露对鲮(Cirrhinus molitorella)的毒性效应,为护肤品的安全使用和污染控制提供科学依据。配置不同浓度(0 g·L^-1、0.5 g·L^-1、0.75 g·L^-1、1.00 g·L^-1)的护肤品暴露鲮48h,在暴露时间为0、6 h、12 h、24 h、36 h、48 h时,测定鲮肝脏中超氧化物歧化酶(SOD)活性、谷胱甘肽转移酶(GST)活性、谷肮甘肽过氧化物酶(GSH)含量,观察并记录鲮的死亡情况,计算三种护肤品对鲮的半致死浓度(LC50)。结果表明:三种护肤品的暴露浓度为1.00 g·L^-1时,SOD酶和GST酶活性达到最大;三种酶活性都是随着时间的增加呈现先增后减的变化规律;护肤品B、C暴露48h时,GSH酶被抑制;护肤品A、B、C 48h的LC50分别为807 mg·L^-1、973 mg·L^-1和1147 mg·L^-1。护肤品A、护肤品B和护肤品C的毒性分别为中毒物质,中毒物质和低毒物质,中高价位的护肤品对鲮的伤害相对较小。     

桦褐孔菌提取物抗氧化活性研究

以乙酸乙酯和甲醇为提取剂,采用索氏提取法,剩余残渣采用热水浸提,最终得到桦褐孔菌不同极性提取物,对其DPPH自由基、羟基自由基及超氧阴离子自由基清除活性作用进行了研究,确定桦褐孔菌的抗氧化能力,为深入研究和开发桦褐孔菌功能性食品奠定理论基础。实验结果表明桦褐孔菌具有较好的抗氧化活性,其中乙酸乙酯提取物的DPPH自由基清除率、羟基自由基清除率和超氧阴离子自由基清除率均高于其他两组分及BHT,桦褐孔菌提取物有望成为功能性食品组分中合成抗氧化剂的天然替代品。     

大鲵皮肤色素提取工艺及抗氧化研究

为优化大鲵皮肤黑色素的提取工艺条件,探讨大鲵皮肤黑色素组成成分及体外抗氧化活性,采用酶法和碱溶酸沉法提取大鲵皮肤黑色素,以氢氧化钠浓度、液料比、提取温度为影响色素提取率因素,优化黑色素提取工艺条件,用紫外-可见光谱仪、红外光谱仪和超高效液相质谱仪测定黑色素的光谱特性,测定其抗氧化性。结果表明:大鲵皮肤黑色素最佳提取工艺条件为氢氧化钠浓度1.5 mol/L、液料比1∶15、提取温度45℃,黑色素提取率达0.65%。大鲵皮肤黑色素的紫外最大吸收波长为214 nm,由真黑色素和脱黑色素两种色素组成,其对超氧阴离子自由基的清除率为30.51%,对羟基自由基的清除率为54.17%。大鲵皮肤黑色素具有一定的体外抗氧化能力。     

Effect of phototherapy on oxidant/antioxidant status: a randomized controlled trial

In order to evaluate the effect of different types of phototherapy on oxidant/antioxidant status in hyperbilirubinemic neonates, an interventional randomized control trial was conducted on 120 neonates ≥35 weeks’ gestational age with indirect hyperbilirubinemia reaching phototherapy level. This study is registered with ClinicalTrials.gov as NCT03074292. Neonates were assigned to three groups; 40 neonates received conventional phototherapy, 40 received intensive phototherapy and 40 received blue light-emitting diodes (LED) phototherapy. Complete blood count (CBC), total serum bilirubin (TSB), total antioxidant capacity (TAC), malondialdehyde (MDA), nitric oxide (NO), copper (Cu), zinc (Zn), and iron (Fe) levels were measured before and 24?hours after phototherapy. TSB decreased postphototherapy in all three groups (p < .05 for all), with significantly lower levels following intensive and LED phototherapy compared to conventional phototherapy (p < .05 for both). TAC decreased postphototherapy in the three groups (p < .05 for all). MDA and NO increased postphototherapy (p < .05 for all), with the intensive phototherapy group having the highest levels followed by the conventional while LED phototherapy group showed the lowest levels in comparison to the other groups (p < .05). Cu, Zn and Fe increased postphototherapy in all three groups (p < .05 for all). Positive correlations were found between postphototherapy TSB with TAC, Cu and Zn (p < .05) and negative correlations with MDA, NO and Fe (p < .05) among neonates of the 3 studied groups. In conclusion, different photo therapies have an impact on oxidant/antioxidant balance and are associated with increased oxidative stress markers with the LED phototherapy being the safest.     

New antioxidant flavonoid isolated from Leuzea carthamoides

A new natural flavonoid patuletin 3′-β-xylofuranoside was isolated from Leuzea carthamoides leaves. The antioxidant activity of this compound was evaluated by the DPPH radical assay and ferric reducing antioxidant power (FRAP) assay, and the results were compared with those for trolox and quercetin. DPPH radical scavenging activity of the tested compounds was expressed by the parameter EC₅₀: patuletin 3′-β-xylofuranoside (56.0 μM), trolox (27.8 μM), and quercetin (25.3 μM). The ferric reducing activity of the compounds was demonstrated as FRAP values at 4 and 60?min: patuletin 3′-β-xylofuranoside (28.4 μM, 35.8 μM), trolox (19.3 μM, 20.2 μM), and quercetin (54.3 μM, 79.9 μM). The structure/activity relationship of the flavonoid is also discussed. The results indicate significant antioxidant potency of patuletin 3′-β-xylofuranoside.     

Integrated evaluation the antioxidant activity of epicatechin from cell dynamics

Oxidative damage has been implicated in the pathogenesis of numerous disorders by affecting the normal functions of several tissues. Further, oxidative stress acts within cells to influence cell morphology and the behavior of cell migration. The movement and migration of cells are crucial during the development of organisms as they transition from embryo to adult, and for the homeostasis of adult tissues. Epicatechin (EC) is a natural flavonoid derived mostly from tea, chocolate, and red wine. We investigated the protective impact of EC on D-galactose(D-gal)/rotenone-injured NIH3T3 cells and found alterations in cell dynamics throughout the procedure. The results reveal that D-gal/rotenone stimulation can cause the cell area to expand and the number of cellular protrusions to increase. EC intervention can considerably minimize the oxidative damage of rotenone on NIH3T3 cells (p < 0.05) but showed little influence on cell damage induced by D-gal. Furthermore, the corrective ability of EC as an antioxidant is reflected in a dose-dependent effect on cell movement, including variations in movement speed and distance. Overall, from the perspective of cell morphology and cell motility, EC has a good protective impact on cells harmed by rotenone induced oxidative damage, as well as corrective properties as an antioxidant to balance intracellular oxidative stress, which allowing for a more comprehensive evaluation of antioxidant performance of EC.     

Chemical constituents from Tribulus terrestris and screening of their antioxidant activity

Two oligosaccharides (1, 2) and a stereoisomer of di-p-coumaroylquinic acid (3) were isolated from the aerial parts of Tribulus terrestris along with five known compounds (4–8). The structures of the compounds were established as O-β-d-fructofuranosyl-(2 → 6)-α-d-glucopyranosyl-(1 → 6)-β-d-fructofuranosyl-(2 → 6)-β-d-fructofuranosyl-(2 → 1)-α-d-glucopyranosyl-(6 → 2)-β-d-fructofuranoside (1), O-α-d-glucopyranosyl-(1 → 4)-α-d-glucopyranosyl-(1 → 4)-α-d-glucopyranosyl-(1 → 2)-β-d-fructofuranoside (2), 4,5-di-p-cis-coumaroylquinic acid (3) by different spectroscopic methods including 1D NMR (¹H, ¹³C and DEPT) and 2D NMR (COSY, TOCSY, HMQC and HMBC) experiments as well as ESI-MS analysis. This is the first report for the complete NMR spectral data of the known 4,5-di-p-trans-coumaroylquinic acid (4).The antioxidant activity represented as DPPH free radical scavenging activity was investigated revealing that the di-p-coumaroylquinic acid derivatives possess potent antioxidant activity so considered the major constituents contributing to the antioxidant effect of the plant.     

计算机模拟酶解制备驴乳清蛋白抗氧化肽的研究

本文选用驴乳清蛋白为原材料,以DPPH自由基清除率为指标,利用计算机模拟酶解驴乳清蛋白,筛选出能够产生抗氧化活性肽的最适蛋白水解酶,以pH、酶解温度、酶底比(质量比)为自变量,采用Design-Expert V8.0.6设计响应面试验,确定以α-胰凝乳蛋白酶酶解驴乳清蛋白制备抗氧化肽的最佳工艺条件。结果表明在底物浓度4%,酶解时间4 h的条件下,当温度达到39℃,pH 8,酶底比4%时得到的酶解肽抗氧化活性最强,10 mg/mL驴乳清蛋白酶解肽的DPPH自由基清除率最高可达46.23%。     

水母胶原蛋白抗氧化活性研究

提取水母胶原蛋白,观察其体内外抗氧化作用。体外采用邻苯三酚自氧化法观察水母胶原蛋白对超氧阴离子(·O2-)的清除作用,采用Fenton反应体系观察对羟自由基(·OH)的清除作用;体内观察水母胶原蛋白对小鼠血清、肝脏、大脑中超氧化物歧比酶(SOD)、过氧化氢酶(CAT),丙二醛(MDA)含量的影响。结果表明:水母胶原蛋白对·O2-、·OH具有良好的清除作用,呈一定的剂量依赖关系,能明显提高小鼠血清、肝脏、大脑中的SOD、CAT含量,能在一定程度上降低血清、肝脏、大脑中的MDA水平。因此,水母胶原蛋白具有显著的抗氧化生物活性。