荔枝叶中黄酮甙元的分离提纯及其表征

以荔枝叶为原料提取黄酮,黄酮经水解、溶剂萃取、柱层析等方法,得到高纯度甙元;经熔点、薄层色谱、液相色谱、红外光谱、核磁共振法等分析方法进行结构表征,证实荔枝叶含有黄酮甙,其甙元为槲皮素和山奈酚。     

荷叶黄酮的提取加工技术

荷叶黄酮,是睡莲科植物莲叶中提取出的一种黄酮类物质,它是荷叶中的有效成分之一。在荷叶中主要以荷叶甙的形式存在,荷叶甙在新鲜荷叶中含量约为0．1％,其分子结构表明,荷叶甙是以槲皮黄素为甙元,通过3-C位置的羟基与葡萄糖-葡萄糖醛酸形成甙键。荷叶甙与槲皮甙、异槲皮甙不同,虽然它们的甙元都是槲皮黄素。     

荔枝叶黄酮提取及其含量测试

采用沸水提取荔枝叶,水提取液经D-101大孔吸附树脂吸附富集,然后用80％的乙醇洗脱,对荔树叶中的总黄酮进行提取、精制;对提取出的黄酮进行水解,用高压液相色谱进行标准品对照分析,首次发现其黄酮甙元为槲皮索和山奈酚,并利用HPLC检测其含量。试验表明叶中总黄酮含量为0．49％。     

云南松花粉中黄酮类成分研究初报

用现代波谱技术与化学分析联用的方法，对云南松花粉的黄酮类成分进行了分析，并与具有黄酮母体结构的芦丁、槲皮素和黄芩甙标准对照品进行对比分析，经薄层色谱及显色反应，鉴定出云南松花粉的黄酮类化合物成分，主要为黄酮和黄酮醇类，其次是二氢黄酮醇类，另外还有少量黄烷醇类的花青素。     

云南松花粉中黄酮类成分研究初报

用现代波谱技术与化学分析联用的方法，对云南松花粉的黄酮类成分进行了分析，并与具有黄酮母体结构的芦丁、槲皮素和黄芩甙标准对照品进行对比分析，经薄层色谱及显色反应，鉴定出云南松花粉的黄酮类化合物成分，主要为黄酮和黄酮醇类，其次是二氢黄酮醇类，另外还有少量黄烷醇类的花青素。     

油茶叶的黄酮成分研究

从油茶叶的甲醇提取物中分离得到三种黄酮体化合物,经分析为:1.槲皮素;2.槲皮素-3-0-鼠李吡喃糖甙;3.槲皮素-3-0-葡萄吡喃糖-(6→1)-鼠李吡喃糖甙。     

广西甜茶叶片的营养成分及开发利用价值研究

研究发现甜茶叶片的营养保健成分 :蛋白质、氨基酸、维生素A、维生素B1、维生素C、维生素E、叶酸、尼克酸、类胡萝卜素、黄酮甙、茶多酚、甜茶素、纤维素、微量元素等含量丰富 ,特别是甜茶黄酮甙、茶多酚、甜茶素等含量的存在 ,使甜茶叶片更具营养保健功能和开发价值     

超滤在纯化银杏叶黄酮甙中的应用

采用国产中空纤维超滤设备，对银杏叶的乙醇提取液进行分离，去掉部分原花青素、高分子单宁、鞣质、蛋白质和糖类等杂质，澄清透明的超滤液经聚酰胺树脂吸附，得到银杏黄酮甙产品。ＨＰＬＣ检测，其含量在４５％左右，得率为０．５％～０．７％     

葛根产品开发盼合作

1、企业或项目单位现具备的基本条件贵州省凯里兰洋食品有限责任公司是民营科技企业，本公司1997年7月成立，有中级职称以上科技人员15人，有固定的办公楼和生产场地．研究开发的产品经省级食品权威科研单位检验合格。2、项目开发的主要内容、目的、意义葛根又名葛藤，藤本植物，块根富含淀粉、多种氨基酸．尤其是含有抗衰老元素硒达33．Ug／100g．其主要成份有大豆素、大豆甙、大豆甙元、葛根粉、葛根黄酮等。葛根有扩张冠状动脉和脉血管、降压、抑制血小板聚集、解热透疹、生津止渴、解毒止泻等效果．对防治牙出血、唇裂、咳嗽、高血压有…     

几种杨树树皮中酚甙和酚酸类化合物的初步研究

从毛白杨等四种树皮的热水浸提物中分离出二种酚甙结晶,经熔点测定、元素分析、薄层色谱、红外光谱、质谱等手段鉴定为水杨甙(Salicin)和杨属灵(Pop-ulin)。对树皮中的酚酸也用高效液相色谱进行分析,发现上述树皮中含有对-羟基苯甲酸等五种酚酸。     

Variance of common flavonoids by brand of grapefruit juice

Nine commercial brands of grapefruit juice were analyzed for their flavonoid content by HPLC to determine if significant brand-to-brand variance in grapefruit juice flavonoid content exists. Flavonoid glycosides narirutin, naringin, hesperidin, neohesperidin, didymin, and poncirin have been identified in all the grapefruit juices examined. The aglycone quercetin was detected in only two brands. All the juices were free from methoxylated flavonoid aglycones. There was a significant difference in the amounts of total flavonoids and individual flavonoids in the nine brands. The concentration of total flavonoids ranged between 19.44 and 84.28 mg/100 ml juice. Naringin was found to be the major flavonoid followed by narirutin and hesperidin. Their concentrations ranged from 14.56 to 63.8; 2.25 to 12.20; and 0.24 to 3.12 mg/100 ml juice, respectively.     

Free radical scavenging activity of different extracts and some constituents from the leaves of Ligustrum vulgare and L. delavayanum

The free radical scavenging activity of the water infusions, different organic solvent extracts and some constituents from Ligustrum vulgare and Ligustrum delavayanum leaves was assessed with the aid of DPPH radical. Among the samples screened, water infusions had the strongest free radical scavenging capacity. From the tested compounds scavenging active flavonoid aglycones are present in the most active chloroform fractions from both leaves samples.     

超声波提取刺五加主要酚苷及苷元的工艺优化

采用超声波提取的方法从刺五加根茎中提取紫丁香苷、刺五加苷E和异秦皮啶等有效成分,考察超声波提取时间、乙醇体积分数、料液比和超声波功率等因素对提取的影响.应用Box-Behnken中心组合进行3因素3水平的试验设计,分别以3种目标产物的得率与纯度作为响应值进行工艺优化.响应面法优化后提取工艺条件为:乙醇体积分数59.66%、刺五加与乙醇的料液比1:6(g:mL)、提取时间44.9 min、超声波功率150 W.最佳条件下浸膏中刺五加主要酚苷及苷元的质量分数为2.923%,其中含紫丁香苷1.3%,刺五加苷E 1.53%,异秦皮啶0.093%;浸膏得率为6.77%.     

4个银杏主要产区的银杏花粉营养成分比较研究

以4个银杏主产区百年银杏雄树花粉为材料,分别测定了花粉中黄酮、内酯、VC、VB1、VB2、氨基酸的含量,结果表明:四大产区的银杏花粉营养成分存在显著差异,总黄酮、内酯、VC、VB1、VB2、氨基酸平均含量分别为18.760 1 mg/g、5.159 6 mg/g、14.955 6 mg/100g、12.948 3 mg/100g、65.071 5 mg/100g、23.649 4 g/100g,泰兴和南雄的总黄酮含量较高,分别为20.446 5 mg/g和19.579 9 mg/g;南雄地区的内酯含量最高,为7.822 0 mg/g,郯城地区的最少,为2.899 5 mg/g;泰兴的花粉VC含量最高,为27.219 8 mg/100g,桂林地区的含量最少,为6.365 4 mg/100g;桂林地区的VB1含量最多,为22.391 9 mg/100g,泰兴地区的最少,为7.234 7 mg/100g;桂林地区的花粉VB2含量最多,为93.6442 mg/100g,郯城地区的最少,为49.655 0 mg/100g。总体来看,银杏花粉的品质比较优秀,但开发应因地而异,结合营养元素含量有针对性地进行开发。     

银杏叶黄酮含量变化规律及其干燥方式的研究

对不同部位,不同条件下的银杏叶黄酮含量,银杏叶的干燥变化等进行了比较分析,结果表明：不同品种及雌雄株的成年银杏叶黄酮含量无显著差异;实生苗叶比嫁接苗叶黄酮含量高;５年生以下幼树叶含量高;     

Antifungal activity of Rubia tinctorum, Rhamnus frangula and Caloplaca cerina

The results of a preliminary antifungal screening of the methanol extracts and the major anthraquinone aglycones, alizarin and emodin, of Rubia tinctorum and Rhamnus frangula in comparison with the antifungal activity of the anthraquinone-containing lichen Caloplaca cerina and its main secondary metabolite parietin are reported.     

Changes in soluble-phenol content of Norway-spruce (Picea abies) phloem in response to wounding and inoculation with Ophiostoma polonicum

The aim of this study was to investigate the temporal changes in Norway-spruce (Picea abies) phloem phenolics during wound-induced response. Two Norway spruces were inoculated with Ophiostoma polonicum and sterile agar; unwounded phloem was simultaneously tested as control. Both unwounded and inoculated phloem were then sampled 6, 11, 21, 30, and 60 days later. Monophenols were analysed by HPLC, and the tanning capacity of the phloem extracts was estimated from their ability to precipitate proteins. The response to inoculation was characterized by radical changes in the phloem phenolic composition. Initially, an increase in (+)-catechin concentration was observed, concomitant with a slow decrease in both glycoside concentrations and tanning capacity. After day 6, this decrease was accelerated in the event of fungus inoculation. The appearance of aglycones did not take place during the decrease in glycosides, but was delayed. The phenolic response of Norway-spruce phloem to inoculation is modulated by the presence of the fungus and is focused on the formation of insoluble compounds.     

Antiproliferative and antiangiogenic effects of flavone eupatorin, an active constituent of chloroform extract of Orthosiphon stamineus leaves

Flavone eupatorin is one of the constituents of Orthosiphon stamineus, a medicinal herb used in folk medicine in South East Asia for treatment of various disorders. In our study, we investigated the antiproliferative properties of a chloroform extract of the leaves of O. stamineus and of pure eupatorin. The compound was able to reduce the number of viable cancer cells to the same extent as the extract, with IC(50) values in micromolar range. Moreover, both the eupatorin standard and the extract caused cells to arrest in the G2/M phase of the cell cycle. This clearly demonstrates that eupatorin contributes significantly to the overall extract activity. Induction of mitotic catastrophe, accompanied by key molecular events defining apoptosis, is the mechanism of eupatorin-induced cell death. Importantly, eupatorin (at the doses cytotoxic to cancer cells) did not kill normal cells; it only limited migration of HUVEC endothelial cells and their ability to create tubes. The ability of eupatorin to nonspecifically inhibit many protein kinases was proven and is the probable cause of its cellular effects. In summary, eupatorin emerges as a promising agent in anticancer research.     

Biosynthesis of (+)-syringaresinol inLiriodendron tulipifera I: feeding experiments withl-[U-14C]phenylalanine and [8-14C]sinapyl alcohol

To clarify the biosynthesis of syringyl lignans and lignan formation by stereoselective coupling of monolignols, formation of (+)-syringaresinol and (+)-pinoresinol inLiriodendron tulipifera were investigated by means of feeding experiments. Following individual administration ofl-[U-¹⁴C]phenylalanine and [8-¹⁴C]sinapyl alcohol to excised shoots ofL. tulipifera and their subsequent metabolism for 3h, free [¹⁴C] lignans and [¹⁴C] lignan glucosides were extracted from both of the stems and leaves with methanol and divided into an ether fraction and an aqueous one, respectively. The glucosides were hydrolyzed by a combination of cellulase and-glucosidase to liberate [¹⁴C]lignans as aglycones.l-[U-¹⁴C]Phenylalanine was incorporated into free (+)-[¹⁴C]syringaresinol and its glucosides; the (+)-[¹⁴C]syringaresinols in the stems and leaves had 52% enantiomeric excess (% e.e.) and 42% e.e., respectively; and the (+)-[¹⁴C]syringaresinol aglycones from the glucosides in the stems and leaves had 20% e.e. and 22% e.e., respectively. Furthermore, [8-¹⁴C]sinapyl alcohol was incorporated into (+)-[¹⁴C]syringaresinol and its glucosides in the stems. These results suggest that the (+)-enantiomer of syringaresinol was enantioselectively formed from two molecules of sinapyl alcohol inL. tulipifera followed by transformation into the (+)-syringaresinol glucosides, accompanying the formation of racemic syringaresinol by nonselective coupling and the subsequent transformation of the racemate into their glucosides.l-[U-¹⁴C]Phenylalanine was incorporated also into free (+)-[¹⁴C]pinoresinol and its glucosides with 12%–42% e.e.Part of this paper was presented at the 47th Annual Meeting of the Japan Wood Research Society, Kochi, April 1997