抗氧化活性检测方法的研究进展

本文综述了常用的抗氧化活性检测方法,讨论了各种方法的优缺点.     

山黧豆活性成分β-ODAP的检测方法研究进展北大核心CSCD

β-N-草酰-L-α,β-二氨基丙酸(β-N-oxalyl-L-α,β-diaminopropionic acid,β-ODAP)是山黧豆中的一种重要非蛋白氨基酸,与三七中的三七素为同一种次生代谢物,具有止血、兴奋神经、抗菌等多种生物活性。自20世纪60年代和80年代在山黧豆等豆类和三七等植物中分别发现β-ODAP以来,科研工作者建立了多种检测方法。该文对近年来国内外有关检测β-ODAP的传统分析法、高效液相色谱法(HPLC)、色谱-质谱法(GC/LC-MS)、毛细管电泳法及酶学分析法等的基本原理及应用研究进展进行了综述,这些检测方法各有所长,具体选择依实验条件和实验目的而定。其中,柱前衍生化高效液相色谱法是目前应用最广泛的方法,高成本同位素内标的LC-MS则被誉为“金标准”。但特异、快速和低成本的检测方法一直是人们的追求目标,因而进一步完善酶传感器技术是β-ODAP检测领域在将来的主要研究方向。     

功能性低聚糖及其检测方法研究的现状

低聚糖（oligosaccharides）又称寡糖,是由2～10个单糖以直链或分支结构形成的糖类的总称。低聚糖包括普通低聚糖和功能性低聚糖（functional oligosaccharides）。普通低聚糖有蔗糖、麦芽糖、麦芽三糖等。而功能性低聚糖如低聚果糖、低聚半乳糖、大豆低聚糖、低聚异麦芽糖,是一类在人体不被消化,具有特殊生理功能,特别是有益于肠道健康的一类低聚糖,是一种功能性食品的重要基料。     

降胆固醇活性肽检测方法的研究进展

综述近年来国内外胆固醇以及具有降胆固醇活性的小分子肽在体内和体外的检测方法,为研究胆固醇代谢和降胆固醇活性小分子肽的研究提供参考。     

Biochemical and Physiological Evidence that Carnosine Is an Endogenous Neuroprotector Against Free Radicals

1. Carnosine, anserine, and homocarnosine are endogenous dipeptides concentrated in brain and muscle whose biological functions remain in doubt.2. We have tested the hypothesis that these compounds function as endogenous protective substances against molecular and cellular damage from free radicals, using two isolated enzyme systems and two models of ischemic brain injury. Carnosine and homocarnosine are both effective in activating brain Na, K-ATPase measured under optimal conditions and in reducing the loss of its activity caused by incubation with hydrogen peroxide.3. In contrast, all three endogenous dipeptides cause a reduction in the activity of brain tyrosine hydroxylase, an enzyme activated by free radicals. In hippocampal brain slices subjected to ischemia, carnosine increased the time to loss of excitability.4. In in vivo experiments on rats under experimental hypobaric hypoxia, carnosine increased the time to loss of ability to stand and breath and decreased the time to recovery.5. These actions are explicable by effects of carnosine and related compounds which neutralize free radicals, particularly hydroxyl radicals. In all experiments the effective concentration of carnosine was comparable to or lower than those found in brain. These observations provide further support for the conclusion that protection against free radical damage is a major role of carnosine, anserine, and homocarnosine.     

高效液相色谱法测定肌肽滴眼液中L-肌肽的含量及有关物质

目的:建立肌肤滴眼液中L-肌肤的含量测定的HPLC方法.方法:采用Kromasil NH2色谱柱(200 mm × 4.6mm,5 μm),流动相为乙腈-40 mmol·L-1磷酸氢二钾溶液(44:56,磷酸调pH 6.3).流速1.0 mL·min-1,检测波长为210 ml,柱温为35℃.结果:肌肤在9.93～99.3μg·mL-1范围内线性关系良好(r=0.999 8),平均回收率为99.8%(RSD=1.0%,n=9),滴眼液中含L-肌肽的标示百分含量为97.0%～102.0%.结论:该方法操作简便、重复性好、专属性强,可用作肌肤滴眼液中L-肌肽的质量控制.     

Polyphenolic Content and Physiological Activities of Chinese Hawthorn Extracts

Hawthorn polyphenol (HP) was prepared by ethyl acetate treatment of the ethanol extract (HE) of Chinese hawthorn fruit. The concentrations of 15 polyphenols in the HP, HE, extraction residue (HJ), and a hawthorn leaf extract (HF) were determined by HPLC. For HP, the total content of the 15 polyphenols was 21.4%, comprised of 19.7% of procyanidins, 1.21% of chlorogenic acid, and 0.48% of flavonoids, compared to 2.55% for the HE. The yields of procyanidin monomer, dimer, trimer, tetramer, and pentamer were 50.5%, 30.3%, 23.0%, 14.6%, and 12.5% respectively, and the mean degree of polymerization was reduced to 1.39 (HP) from 1.65 (HE). Seven different physiological actions of the four extracts were investigated. The HP showed strong O₂ ^? and ^?OH scavenging capacities (IC₅₀ values of 6.3 μg/ml and 1.1 μg/ml respectively), as well as selective prolyl endopeptidase inhibition (IC₅₀ of 60 μg/ml). The active constituents appeared to be procyanidins.     

腐植酸对植物生理活动的影响

本文介绍了腐植酸的形成、提取、分类以及活性基团等方面的特征。腐植酸能影响植物的多种生理活动,包括植物的生长、营养元素的吸收、蛋白质和核酸的合成、光合作用、呼吸作用以及有些酶的活性等。腐植酸对植物的这些作用受自身不同成分、浓度、植物种类、外界营养条件等多方面的影响。本文也从细胞或分子水平讨论了腐植酸促进植物生长、影响营养元素吸收及促进呼吸作用的机理。