花生不同品种叶片类黄酮含量和相关合成酶活性对PEG胁迫的响应

以花生品种花17、农大818、丰花5号和山花11号为试材,聚乙二醇(PEG)室内砂培法模拟干旱胁迫,研究20%PEG胁迫下花生幼苗叶片中类黄酮含量及相关合成酶活性的变化。20% PEG开始处理后,随胁迫时间延长,幼苗叶中类黄酮含量逐步上升,在胁迫9h达到高峰,之后逐步下降至对照水平,农大818、丰花5号和山花11号均在处理后72h降至对照水平,花17在36h降至对照水平。PEG开始处理后苯丙氨酸解氨酶（PAL）、查尔酮合成酶（CHS）、查尔酮异构酶（CHI）酶活性均逐渐提高,6h后CHS、CHI酶活性达到高峰,9h后PAL酶活性达到高峰,之后下降,4个品种趋势一致。分析表明PEG处理后山花11号和丰花5号的合成酶具有较高的活性和积累速率是其类黄酮快速大量合成的原因,而农大818 CHS酶活性和PAL酶活性提高速率较低限制了其类黄酮的积累,3种酶的活性和积累速率均较低导致花17叶中类黄酮合成少,含量提高慢。相关分析表明PEG胁迫下PAL、CHS、CHI共同调控类黄酮的代谢,胁迫引起PAL、CHS、CHI酶活性改变是类黄酮含量变化的原因。     

微波联合大孔树脂提取腊梅花中总黄酮的研究

[目的]对微波联合大孔树脂提取腊梅花总黄酮的新工艺进行研究。[方法]在不同的提取工艺条件下进行平行试验、正交试验和对比试验。[结果]原料0.500 g的腊梅花粉末,以70%的乙醇溶液作提取剂,提取剂的用量为1∶60(g/ml),微波功率为288 W,在提取时间为450 s下提取次数3为最佳工艺。确定AB-8为腊梅花总黄酮的吸附树脂。其最佳静态吸附工艺条件为:温度30℃,吸附时间3 h;最佳动态解吸工艺条件为:流速2.6 ml/min,上样液pH值4.3,30 ml 70%乙醇洗脱。与溶剂浸提法相比,采用微波法提取腊梅花总黄酮提取时间由20 h缩短为450 s,提取率从79.86%提高到92.23%,而且AB-8分离腊梅花总黄酮分离效果明显,成本低。[结论]微波联合大孔树脂提取腊梅花总黄酮可工业化推广。     

超声波提取桑叶中总黄酮的工艺研究

采用醇提法、超声提取法探讨了从桑叶中提取总黄酮类物质的最佳工艺。试验结果表明:通过单因素试验和正交试验,超声提取效果最好。其最佳条件是:用浓度为70%、按料液比1:15的比例的乙醇浸泡3h,再用超声提取45min,其桑叶中总黄酮类物质的提出率可达2.18%采用聚酰胺树脂为层析柱填充料,对桑叶黄酮的提取液进行了纯化。还通过样品的总黄酮与FeCl3、浓H2SO4等试剂的特征反应对所得提取物进行了定性分析,确定了所得提取物为黄酮类物质。     

Effect of temperature on flavonoid production in pigeonpea [Cajanus cajan (L) Millsp] in relation to nodulation

To ascertain the reasons for poor nodulation of pigeonpea, we studied the effect of high temperature on the production of flavonoids by the pigeonpea host. A high temperature affected flavonoid production by pigeonpea and mungbean. At 37°C pigeonpea root exudates contained four flavonoids and the root extract contained five. The proportion of the second flavonoid in the pigeonpea and the mungbean was higher and the proportion of the third flavonoid was lower at 37°C compared to 30°C. At the higher temperature the flavonoids exuded from pigeonpea roots were same those in the root homogenate.     

酸角叶中总黄酮的提取及清除羟自由基的作用研究

[目的]优选酸角叶中总黄酮的提取条件,并对其清除羟自由基的作用进行研究.[方法]采用乙醇回流法提取酸角叶中的总黄酮,通过单因素确定总黄酮提取的较佳试验条件,并对总黄酮的清除羟基自由基（·OH）的作用进行对比试验.[结果]确定酸角叶中总黄酮的最佳提取条件为：乙醇浓度为70％,料液比为1∶30（W/V,g/ml,下同）,回流温度为85℃,提取时间为2.5 h;在此条件下,酸角叶中总黄酮的提取率为1.83％.羟基自由基（·OH）的清除作用对比试验表明,抗氧化活性大小依次为：提取液中总黄酮＞芦丁＞BHT.[结论]该方法优选了酸角叶中总黄酮的最佳测定条件,并发现其对羟自由基有较强的清除作用.     

不同花色杜鹃花色素成分与稳定性分析研究

[目的]全面分析不同花色杜鹃花的色素成分与稳定性。[方法]以4种不同花色的杜鹃花花瓣(浅红、紫色、白色和粉红色)为试材,对其花色素提取液进行紫外-可见光光谱扫描检测、特征显色反应和稳定性分析。[结果]试验表明,杜鹃不同花色色素不含叶绿素和类胡萝卜素;粉色、浅红色和紫色杜鹃花色素主要由花色素苷和类黄酮化合物组成;白色杜鹃花色素则含非红色的类黄酮化合物以及其他化合物,其花色素不具备邻二酚羟基或邻三酚羟基结构,揭示了杜鹃花色呈现差异的内在本质。紫外-可见光光谱扫描的结果表明,不同花色素溶液中的花色素种类与含量不同。稳定性研究表明,食品添加剂、低价金属离子对色素色泽无不良影响,但碱性环境、氧化还原剂以及Fe3+、Al3+均对其稳定性影响较大,探明了有利于杜鹃花色素稳定的环境条件。[结论]研究可为杜鹃花色素的分离鉴定奠定基础,同时也为天然杜鹃花色素的科学利用提供理论依据。     

几种植物生长调节剂对金银花产量及品质的影响

[目的]探讨矮壮素、缩节胺和多效唑3种植物生长调节剂对金银花产量及品质的影响。[方法]对大田栽培金银花进行喷施矮壮素、缩节胺和多效唑等植物生长调节剂处理,并测定各处理的产量及品质指标,分析在生产中应用于提高金银花产量及品质的潜力。[结果]3种植物生长调节剂均可不同程度提高金银花的单株产量。其中,缩节胺增产效果最为明显,50和200 mg/L的缩节胺使单株产量分别提高了80.25%和79.88%,但3种植物生长调节剂对金银花的品质影响不明显。[结论]喷施植物生长调节剂可作为金银花生产中的增产措施。     

Oral Bioavailability of Quercetin in Horses

Quercetin, one of the most abundant flavonoids in plants, is discussed with respect to health-promoting effects like antioxidative and anti-inflammatory properties. Although most claims regarding biological effects of flavonoids are based on in vitro and ex vivo studies, the use of flavonoid-containing supplements in humans and companion animals has increased in recent years. Flavonoid-containing supplements are also offered for pet and livestock nutrition. However, any systemic effect of a substance within a living subject depends on its bioavailability. Therefore, the aim of the present study was to gain information on the oral bioavailability of quercetin in horses. Four Icelandic horses with a mean body weight (BW) of 315 ± 25 kg (mean ± standard error [SEM]) were fed a test meal (crimped oats 1 g/kg BW) with the addition of quercetin (20 mg/kg BW). Blood samples were collected directly from the jugular vein before and after ingestion of the test meal for 24 hours, and flavonoid content was analyzed by high-performance liquid chromatography. Quercetin was the main metabolite in plasma with intact flavonol structure after β-glucuronidase/sulfatase treatment of blood samples. The area under the plasma concentration–time curve of quercetin accounted for 88% of total flavonols. Forty-seven percent of the quercetin detected in plasma after ingestion of the test meal was not conjugated. In addition to quercetin, the quercetin derivatives isorhamnetin (methylated) and kaempferol were detected in plasma. Although quercetin is orally bioavailable in horses, similar to other monogastric species, the plasma metabolite pattern differs from those found in species investigated previously (rat, dog, pig, and human).     

Variation in concentrations of major bioactive compounds in Hypericum perforatum L. from Lithuania

The growing demand for the medicinal plant, Hypericum perforatum, is not being met by available supply in many countries. The conditions for obtaining quality crude drug should be thoroughly studied to ensure adequate supply. The current study describes the variation of major bioactive compounds in different accessions of H. perforatum (Hypericaceae) in two floral development stages. Two extraction procedures were evaluated for the quantification of the major bioactive compounds in H. perforatum. The Soxhlet extraction technique was demonstrated to be more effective with higher extraction yields. The contents of rutin, hyperoside, quercitrin, quercetin, and 3,8″-biapigenin were determined by high performance liquid chromatography (HPLC). This procedure was used to establish the variation in the contents of flavonoids in the field-growing H. perforatum and to evaluate factors predetermining that variation with some practical implications for utilization. A significant difference in flavonoid contents between two floral development stages was detected. The results of the study showed that rutin prevailed during the budding stage, whereas quercitrin, quercetin, and 3,8″-biapigenin were dominant during the full-flowering stage. The contents of hyperoside were similar in both developmental stages of the plants. The highest amounts of the most bioactive compounds were observed in the full-flowering stage, which could therefore be considered the best stage for the harvesting of the raw material of H. perforatum, known as Hyperici herba in pharmaceutics. The study revealed evident intraspecific variations in the flavonoid contents of H. perforatum. Several chemotypes were recognized by qualitative and quantitative differences in flavonoids. Qualitative analysis of the flavonoid contents confirmed the presence of the chemotype of H. perforatum containing no rutin, though the chemotype with higher levels of both rutin and hyperoside was more frequent. The accessions of H. perforatum also showed remarkable differences in chemical composition depending on the origin of plants. Therefore, employing the correct developmental stage for the harvesting of the selected accessions of H. perforatum is highly recommended for the quality production of the drug Hyperici herba.     

基于微波提取法的茼蒿中黄酮类物质提取工艺优化

[目的]优化茼蒿中黄酮类物质的提取工艺。[方法]采用单因素试验考察乙醇体积分数、料液比、微波功率、提取时间等因素对茼蒿中黄酮类物质提取率的影响,并用正交试验对其提取工艺进行优化。[结果]微波提取茼蒿中黄酮类物质的最佳工艺条件为：乙醇体积分数60%,料液比1∶20（g∶ml）,微波功率为解冻档,提取时间为120 s。在此条件下提取茼蒿中黄酮类物质的提取率为0.319%。[结论]利用微波法提取茼蒿中总黄酮类物质,具有简单实用的特点,可大大缩短提取时间,达到省时、节能和高效的目的。