山楂叶·果和籽提取物抑菌作用研究

[目的]研究山楂叶、果和籽提取物对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌和黑曲霉的抑制作用,为天然食物添加剂研发提供参考。[方法]70％乙醇提取山楂叶、果和籽中的黄酮类物质,采用分光光光度法测定其含量,并对其抑菌作用进行了研究。[结果]山楂叶、果和籽提取液中总黄酮含量分别为0．911、0．752．0．267mg／ml;山楂叶、果和籽提取物对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌的抑制效果明显,对黑曲霉没有抑制效果。[结论]山楂叶、果和籽提取物均可以作为一种具有抑菌功能的食品添加剂进行开发和利用。     

菠萝皮中黄酮类物质的提取工艺研究

[目的]为菠萝皮的开发利用提供依据。[方法]以烘干后粉碎的菠萝皮为原料,乙醇为提取剂,采用超声波辅助法提取其中的黄酮类物质,通过单因素试验研究料液比、提取剂浓度、提取温度和超声时间对黄酮提取率的影响,并通过正交试验对提取工艺条件进行优化。[结果]单因素试验结果表明,黄酮提取率随料液比、提取剂浓度、提取时间的增加呈先升高后降低趋势,最佳料液比、提取剂浓度、提取温度和超声时间分别为1∶20,70%,75℃和40min;4个因素对黄酮提取率的影响依次为提取温度〉提取剂浓度〉料液比〉超声时间,最佳提取条件为料液比1∶25、提取剂浓度70%、提取温度70℃、超声时间40min,此条件下黄酮的提取率达0.543%。[结论]该研究确定了超声波辅助法提取菠萝皮中黄酮类物质的最佳工艺。     

微波辅助法提取山楂黄酮类化合物的工艺条件研究

[目的]探讨微波辅助法提取山楂中黄酮类化合物的工艺。[方法]采用单因素试验和正交试验,研究微波处理时间、微波功率、乙醇浓度和液固比4个因素对提取山楂黄酮类化合物的影响。[结果]最佳提取工艺条件为：液固比60∶1、乙醇浓度80%、微波处理时间60 s、微波功率420 W。在此工艺条件下,提取率达到3.47%。[结论]该工艺条件适合于提取山楂中黄酮类化合物。     

大叶白麻叶总黄酮提取方法研究

通过不同的方法提取大叶白麻叶的总黄酮,比较不同提取方法的提取率及提取物中总黄酮的含量,从而探讨最佳提取方法。     

茶叶中黄酮类化合物对羟自由基清除实现抗氧化功能研究

茶叶中黄酮类化合物是一种天然抗氧化物质，通过对羟自由基清除作用，实现抗氧化作用。茶叶有较强的的抗氧化作用，是因其黄酮类化合物有清除自由基的功能。     

The perinatal development of the gastrointestinal tract in piglets can be modified by supplementation of sow diet with bioactive substances

Dietary bioactive substances involving taurine, l-carnitine, polyunsaturated fatty acids, flavonoids and antioxidants were shown to control the perinatal development in mammals. A blend of bioactive substances was used to supplement the diet of sows according to the optimal needs of their offspring. Our study aimed to examine the development of gastrointestinal tract in their offspring as compared to the offspring from control sows fed with standard diet. The supplemented diet was given from the gestation day 80 until the end of lactation period. One piglet from each litter was sacrificed on postnatal days 1 (i.e., unsuckling neonates), 2, 4, 7, 14, and 28 for tissue sampling. At birth, the stomach relative weight was larger in the supplemented group, and the small intestine relative weight was smaller as compared to control. These differences disappeared within 1–4 postnatal days. The stomach weight was larger at postnatal day 28 in the supplemented group as compared to control. Gastric protein content and the proteolytic activity in the offspring of the supplemented sows showed after birth a tendency to increase as compared to control, though the differences disappeared after the fourth postnatal day. In conclusion, the supplementation of sow diet with dietary bioactive substances affected primarily the prenatal development of the stomach and small intestine in their offspring.     

Antimicrobial activity of flowers from Anthemis cotula

The flavonoid containing total extract of Anthemis cotula flowers, tested at the concentration of 200 μg/ml, showed interesting antimicrobial activity against both Gram-negative and Gram-positive microorganisms.     

Induction of flavonoid production by UV-B radiation in Passiflora quadrangularis callus cultures

Callus cultures from several species of Passiflora were initiated in vitro, and their capacity to produce four glycosyl flavonoids (orientin, isoorientin, vitexin, isovitexin) was analysed. The aim of the present work was to examine the possible role of UV-B irradiation and elicitation with methyl jasmonate (MJ) on the production of these compounds in callus cultures. All the species tested (P. incarnata, P. quadrangularis, P. edulis) formed friable callus from leaf explants after 4 weeks on medium supplemented with kinetin and 2,4-dichlorophenoxyacetic acid. Among them, P. quadrangularis turned out to have a faster growth rate and a more friable texture, and was therefore chosen for experiments with elicitors. In callus cultures only small amounts of isoorientin were found, while the concentration of the other flavonoids was below the detection limit. UV-B irradiation of calluses was able to increase the production of all four glycosyl flavonoids. After a 7-day exposure of cultures to UV-B light, the production of isoorientin reached concentrations similar to those found in fresh leaves from glasshouse-grown plants. Elicitation with methyl jasmonate also enhanced orientin, vitexin and isovitexin concentrations, even though the stimulation was about 6-fold weaker for orientin and vitexin and about 40-fold for isovitexin, than that exerted by UV-B treatment. Callus cultures treated with the UV-B dose which most enhanced flavonoid production showed a higher antioxidant activity compared to untreated calluses, with an increase ranging from 28% to 76%. Results show that the secondary metabolite biosynthetic capacity of Passiflora tissue cultures can be enhanced by appropriate forms of elicitation.     

Girdling and gibberellic acid effects on yield and quality of a seedless red table grape for saving irrigation water supply

Table grapes need of substantial water supply for achieving commercial requirements. Viticulture practices such as girdling (G) and gibberellic acid (GA) application, as well as water supply, can improve table grape quality. The study, which was conducted in two consecutive seasons (2010–2011), aimed to assess the counterbalance effect of these viticulture practices on yield and quality parameters and flavonoids composition in case of a significant and unusual irrigation water reduction (40%) applied to a table grape variety. The data from the two-way ANOVA and PCA analyses indicated that viticulture practices were clearly related to anthocyanins and flavonols variations whereas water management appeared mainly involved in the yield parameters variability. Specifically, the reduced water supply (RWS) decreased the grape yield (−20%) with respect to full water supply (FWS); by contrast GA, G, and G × GA treatments determined an increment of grape production ranging from 10 to 23%, independently from irrigation strategy. Moreover, G, in particular applied to RWS grapes, was able to improve the total soluble solids over titrable acidity (TSS/TA), a ratio strictly related to the quality perception by the consumer. Total anthocyanins were found positively linked to FWS whereas flavanols content was indifferent to water management. Instead viticulture practices seemed to have a greater impact on anthocyanin composition, considering that in RWS grapes under GA condition, higher contents of malvidin and peonidin (mainly responsible for the color stability of the skins) were revealed. Furtheremore, catechins and rutin appeared significantly enhanced by G and G × GA, and GA, respectively. From gathered findings, it can be concluded that suitable viticulture practices can allow a sensible reduction of water supply during table grape growth cycle without detrimental effects on yield and quality.     

板栗中黄酮类化合物的提取及结构初步鉴定

[目的]探讨板栗中黄酮类化合物提取的最佳工艺条件及板栗黄酮的结构。[方法]采用系列单因素和正交试验设计,通过吸光度测定,以黄酮类化合物提取率为考核指标,对影响提取的因素进行研究,并通过颜色反应和图谱对板栗黄酮的结构进行初步鉴定。[结果]板栗中黄酮类化合物的最佳提取工艺为：料液比1：50,温度60℃,提取时间5h,乙醇浓度80%。最佳提取条件下黄酮类化合物提取率可达0.51%。板栗中黄酮类化合物为具有7-OH结构或A环邻位双羟基结构的黄酮类、黄酮醇类、异黄酮醇类、黄烷酮类、查尔酮类。[结论]该研究为板栗中的黄酮类化合物的有效提取和结构鉴定提供了理论基础。