山楂叶黄酮的超声提取、精制及抗氧化性研究

通过单因素实验和正交实验设计探讨了山楂叶黄酮的超声辅助提取工艺条件，采用溶剂萃取法对粗提物进一步除杂精制，并对提取物的抗氧化性能进行了研究。实验结果表明：山楂叶黄酮的最适宜提取工艺是温度80℃～85℃，液料比（乙醇体积：原料质量）18：1，用60％乙醇超声提取2次，每次40min，然后再70℃，回流提取1h。精制后。黄酮在甲醇：水：丙酮1：2：2体系中进行聚酰胺薄层色谱分离效果最好，得到4个黄酮斑点。山楂叶黄酮对猪油抗氧化能力较强，Vc具有很好的正协同效应。     

Flavones: Six Selected Flavones and Their Related Signaling Pathways That Induce Apoptosis in Cancer

Cancer is a horrific disease that, to date, has no cure. It is caused by various factors and takes many lives. Apoptosis is a programmed cell death mechanism and if it does not function correctly in cancer cells, it can lead to severe disease. There are various signaling pathways for regulating apoptosis in cancer cells. Flavonoids are non-artificial natural bioactive compounds that are gaining attention as being capable of for inducing apoptosis in cancer cells. Among these, in this study, we focus on flavones. Flavones are a subclass of the numerous available flavonoids and possess several bioactive functions. Some of the most reported and well-known critical flavones, namely apigenin, acacetin, baicalein, luteolin, tangeretin, and wogonin, are discussed in depth in this review. Our main aim is to investigate the effects of the selected flavones on apoptosis and cell signaling pathways that contribute to death due to various types of cancers.     

山西老陈醋中总黄酮含量的测定

采用亚硝酸钠-硝酸铝-氢氧化钠显色法在510nm处测定山西老陈醋中的总黄酮,结果显示,该方法在20min内测定稳定,在中性条件下山西老陈醋中总黄酮的提取量最大,其含量为1525.30mg/L,相对标准偏差(RSD)为0.95％(n=6),加标回收率在93.60％～97.65％之间.该方法操作简单、重现性良好、准确度较高,可作为山西老陈醋中总黄酮含量测定的参考方法.     

超声波-表面活性剂协同提取桑叶总黄酮

研究桑叶中总黄酮的超声波-表面活性剂协同提取的工艺条件。以总黄酮得率为考察指标,在单因素的基础上,利用正交试验优化提取工艺条件为:Tween 80的质量分数为1.5%,提取时间45min,料液比1:30,提取温度30℃。超声波-表面活性剂协同提取是一种快速、高效的提取方法。     

陶瓷微滤膜纯化菊花黄酮的工艺研究

目的:研究无机陶瓷微滤膜分离纯化菊花总黄酮提取液,确定最佳的操作工艺条件。方法:以菊花总黄酮得率和膜通量稳定性为评价指标进行实验,对操作压力、溶液温度和膜的规格进行了优化。结果:最佳工艺条件为无机陶瓷膜孔径0.5μm、溶液温度50℃、操作压力0.30MPa,在此条件下,能使菊花黄酮达到较好地除杂和澄清的效果,菊花总黄酮转移率达90%以上,提取固形物中黄酮含量为19.81%,同时纯化过程稳定。结论:无机陶瓷微滤膜纯化菊花总黄酮提取液工艺简单可靠。      

酶解-超声波-表面活性剂协同提取桑叶总黄酮工艺研究

研究桑叶中总黄酮的酶解-超声波-表面活性剂协同提取的工艺条件.以总黄酮提取率为考察指标,对酶解温度、pH值、Tween-80质量浓度、提取时间进行单因素试验.在单因素试验基础上,利用正交试验优化总黄酮提取工艺条件.结果表明,最佳工艺参数为:酶解温度50℃,pH值6.5,Tween-80质量浓度1.00％,提取时间50min.酶解-超声波-表面活性剂协同提取是一种快速、高效的提取桑叶总黄酮方法.     

Antifungal action and inhibitory mechanism of polymethoxylated flavones from Citrus reticulata Blanco peel against Aspergillus niger

Polymethoxylated flavones (PMFs), isolated from the peels of Citrus reticulata Blanco, were identified and quantitated as tangeretin (TAN) (33.87%), nobiletin (NOB) (20.98%), 5-demethylnobiletin (3.52%), tetramethyl-o-scutellarein (1.61%), tetramethyl-o-isoscutellarein (1.23%), pentamethoxyflavone (1.08%) and sinensetin (0.35%). PMFs are promising natural antimicrobial compounds with potential applications in the food industry. The antifungal effects of PMFs on Aspergillus niger (A. niger) were evaluated by microbroth dilution assay and growth curve determination. The minimum inhibition concentration (MIC) of PMFs extract and of TAN against A. niger was determined to be 0.12 mg/mL and 1.5 mg/mL respectively. PMFs affected the permeability of cytomembrane, resulting in instant increased flux of K⁺ and increased relative electrical conductivity. PMFs also dose-dependently reduced the chitin production. These results suggest that the antifungal effects of PMFs could be explained by the permeability change of cytomembrane and the fragility of cell walls caused by chitin inhibition.     

Citrus phenylpropanoids and defence against pathogens. Part II: Gene expression and metabolite accumulation in the response of fruits to Penicillium digitatum infection

The effect of infection of Citrus sinensis (var. Navelina) fruits with Penicillium digitatum was studied at gene expression and metabolite levels. In this study, expression of genes involved in the phenylpropanoid pathway was studied in the flavedo (outer coloured part of the peel) and albedo (inner white part) in response to pathogen infection. Results of the time-course experiment showed that maximal expression of 10 out of 17 phenylpropanoid genes analysed occurred at 48 h post-inoculation, when decay symptoms started to appear, and mRNA levels either kept constant or decreased after 72 h post-inoculation. To further investigate the putative involvement of the phenylpropanoid pathway in the defence of citrus fruit, changes in the metabolic profile of both tissues infected with P. digitatum was studied by means of HPLC-PDA-FD. Metabolite accumulation levels along the time course suggest that flavanones, flavones, polymethoxylated flavones and scoparone are induced in citrus fruit in response to P. digitatum infection, although with different trends depending on the tissue.     

大孔吸附树脂分离纯化银杏叶总黄酮的研究

利用4种大孔吸附树脂分离纯化银杏叶总黄酮.结果表明,HPD100型大孔吸附树脂最适合分离纯化银杏叶总黄酮,该树脂的静态饱和吸附量(以干树脂计)为63.8 mg·g-1,静态洗脱率为91.2%,动态饱和吸附-洗脱量为14.0 mg·g-1,洗脱剂为70%乙醇,洗脱剂用量为4倍树脂体积,树脂可重复使用7个周期.     

小麦麸皮总黄酮超声提取工艺研究

以小麦麸皮为原料,乙醇为提取溶剂,对超声波辅助提取小麦麸皮总黄酮工艺进行研究。考察了超声功率、提取时间、乙醇浓度、料液比、提取次数等因素对小麦麸皮总黄酮得率的影响,并通过正交试验对总黄酮的提取工艺进行优化。结果表明,小麦麸皮总黄酮最佳提取工艺为:超声功率600 W,提取时间30 min,乙醇浓度60%,料液比1∶20,提取两次,在最佳条件下总黄酮得率为2.29%。