江西野生枫香活性成分提取及鞣质含量研究

目的 研究我省野生枫香(Liquidambar Formosana Hance)树皮、树叶有效成分提取方法对鞣质含量的影响。方法采用络合滴定法测定提取液中鞣质含量,以分析不同提取方法的效果。实验结果：枫香树皮、树叶中鞣质含量因提取方法的不同而有明显的差别,无水乙醇、乙酸乙酯提取液中鞣质含量分别为12．35％、11．35％。有机溶剂提取比水溶液提取效果更好,枫香树叶中鞣质含量比树皮高。     

蒙药暖宫七味丸中的鞣质含量测定

采取回流提取工艺,在测定蒙药暖宫七味丸中鞣质的含量时使用融合滴定法测定。测得暖宫七味丸中鞣质的平均含量为3.76%,相对标准偏差RSD为0.17%。鞣质具有抑制肠蠕动、收敛及抑菌作用。蒙药暖宫七味丸中鞣质的含量较高,这与其具有预防、治疗胃肠积热、宿食不消等作用相一致。     

土茯苓中鞣质提取工艺的优化

为了提高土茯苓的应用价值,对土茯苓中鞣质的提取工艺进行了探究.以丙酮溶液作为提取剂回流提取,采用络合滴定法测定鞣质的提取量,通过单因素实验和正交实验对土茯苓中鞣质的提取工艺进行优化,并采用精密度实验、重复性实验以及加标回收率实验对方法进行了评价.结果表明,最佳提取工艺为：提取温度70℃、丙酮浓度40％、料液比1：15（g：mL）、提取时间90 min.在此条件下,土茯苓中鞣质的提取量为20.77 mg·g-1.该提取工艺经济可行,方法的精密度高、重现性好.     

朱砂七总鞣质的提取及抗氧化活性研究

考察了朱砂七总鞣质的含量及抗氧化活性.以60%丙酮为溶媒提取朱砂七鞣质,用铁氰化钾还原法测鞣质的还原能力,以Fenton反应为产生·OH模型,以邻苯三酚自氧化反应为产生O2-·模型,用分光光度法测定鞣质对模型中产生的·OH和O2-·的清除作用.结果表明朱砂七鞣质的还原力随浓度的增大而增大,朱砂七鞣质对O2-·和·OH的...     

不同产地诃子全果、果肉及果核中鞣质的含量测定

建立了诃子中总鞣质的含量测定方法,对不同产地诃子全果、果肉及果核中的鞣质含量进行比较。采用磷钼钨酸-干酪素法,以没食子酸为对照品,于768 nm处测定吸光度值,计算鞣质含量。结果表明没食子酸在0.9408~5.649μg/mL浓度与吸光度具有良好的线性关系（r=0.9993）;平均回收率为97.7%, RSD=1.5%（n=6）。诃子果肉中鞣质含量最高,果核中含量最低。该方法准确度高、重复性好,可用于诃子中总鞣质的含量测定。     

天然植物鞣料中鞣质的分析测定

本文选择油松树，白桦树，漆树，柳树，马桑，桃为植物鞣料，研究提取，分离和测定鞣质，非鞣质，水溶物的方法，用过量标准皮粉吸收的和高效液相色谱法对同一植物鞣焙鞣质作定量分析。     

超声波辅助法提取朱砂七鞣质的工艺

通过单因素实验及正交实验对超声波辅助法提取朱砂七鞣质的工艺条件进行优化.确定最佳提取条件为:乙醇体积分数60%、料液比1∶15(g∶mL)、提取温度70℃、提取时间50 min,在此条件下提取2次,提取率为2.00%.超声波辅助法提取朱砂七鞣质工艺简单、省时、节能、提取率高.     

五倍子、桂皮、石榴皮中总鞣质的提取和氨基酸含量测定

目的:从五倍子、桂皮、石榴皮中提取总鞣质并鉴定其氨基酸含量。方法:热回流法提取五倍子、桂皮、石榴皮的总鞣质,用络合滴定法测定其总鞣质的含量。结果:五倍子、桂皮、石榴皮中总鞣质的含量各为34.57%,28.75%,11.85%。结论:热回流提取法提取效率较高,方法简便,易操作,但受热易破坏的成分不易使用。络合滴定法含量测定方法安全可靠,准确度和精密度较高,可由于桂皮中总鞣质的提取及含量测定。     

Box-Behnken响应面法优化枫香树叶总酚酸提取工艺

目的：采用Box-Behnken响应面法优化枫香树叶总酚酸提取工艺。方法：采用分光光度法，以枫香树叶总酚酸含量为评价指标，在单因素试验的基础上，以乙醇浓度、提取时间、提取温度、液料比为考察因素，利用Box-Behnken设计优化超声法提取枫香树叶中总酚酸的最佳工艺。结果：枫香树叶总酚酸最佳提取条件为乙醇浓度67%、提取时间50 min、提取温度63℃、液料比25∶1,总酚酸得率为0.187%,与预测得率0.183%较为接近，无显著性差异。结论：Box-Behnken响应面法优化方法稳定可靠、简便可行，可用于枫香树叶总酚酸的提取。     

茜草不同炮制品的对比研究

利用HPLC和紫外-分光光度法研究茜草炮制前后大叶茜草素和鞣质的含量的变化。色谱条件:色谱柱:Shim-pack VP-ODS柱(4. 6 mm×250 mm,5μm)、流动相:乙腈∶水(65∶35)、流速:1 mL/min、柱温:30℃、检测波长:250 nm、进样量:10μL。茜草生品中大叶茜草素的含量:0. 53%,鞣质的含量:0. 16%;茜草炭中大叶茜草素的含量:0. 35%鞣质的含量:0. 33%。茜草制炭后大叶茜草素的含量降低,鞣质含量升高。     

Do defoliation and subsequent phytochemical responses reduce future herbivory on oak trees?

Perennial plants are thought to respond to partial or complete defoliation by producing new foliage that is less susceptible to herbivores because of induction of allelochemicals. Here, I tested this hypothesis by manually removing primary foliage from branches ofQuercus emoryi (Fagaceae) at two different times in the season and monitoring changes in protein and tannin levels and the amount of herbivory relative to control branches. New, secondary leaves had 2.5 × greater hydrolyzable tannin content than mature foliage of control branches. Condensed tannins, which constitute a relatively low fraction of leaf mass, were lower, while protein content was temporarily greater, in new secondary leaves relative to mature leaves. Despite large increases in hydrolyzable tannins, herbivory levels were greater on refoliated branches than on control branches. New foliage is susceptible to herbivory regardless of when it is produced in the season, possibly because lower toughness and higher water content override any induced or developmentally related changes in allelochemistry. My results do not support the hypothesis that postherbivore changes in phytochemistry protect perennial plants from future herbivory, at least within a growing season.     

Preserving leaves for tannin and phenolic glycoside analyses: A comparison of methods using three willow taxa

Members of the Salicaceae often produce phenolic glycosides and condensed tannins. There is much debate on the best method for the preservation of leaf material prior to chemical analysis. Published results indicate freeze-drying, a method commonly used for tannin analysis, may be inappropriate for phenolic glycosides, unless done in a manner to prevent thawing during the drying process. Another commonly employed method, air-drying, is appropriate for phenolic glycosides but inappropriate for condensed tannins. I present evidence using willow leaves that demonstrates that: (1) leaves freeze-dried in external flasks without temperature control contain lower concentrations of phenolic glycosides (salicortin and 2-cinnamoylsalicortin), (2) air-dried leaves have reduced concentrations of condensed tannins, while (3) vacuum-dried fresh leaves have high concentrations of both phenolic glycosides and condensed tannins. Freeze-drying caused salicortin and 2-cinnamoyl salicortin concentrations to drop by 20 mg/g and 4 mg/g, respectively. Salicin, a product of salicortin and 2-cinnamoyl salicortin degradation, is absent in vacuum-dried leaves, present in air-dried leaves and very high in freeze-dried leaves. Thus, the presence of salicin in this system is an artifact of the preservation technique. Condensed tannin concentrations dropped nearly 20 mg/g when leaves were air-dried. Thus, vacuum-drying fresh leaves allows researchers to quantify phenolic glycosides and condensed tannins from the same leaf material.     

多穗柯甜茶叶黄酮提取及含量测定

文章选用多穗柯甜茶叶为原料,采用沸水提取,水提取渡经D-101大孔吸附树脂吸附富集,然后用75%的乙醇洗脱,对多穗柯甜茶叶中的黄酮进行提取、精制.对提取出的黄酮进行酸水解,利用高效液相色谱,采用保留时间及叠加法定性,证实老叶和嫩叶中均含有两种黄酮,其甙元分别是槲皮索和山奈酚.利用外标法定量,测得嫩叶中槲皮索和山奈酚甙元...     

Methods and pitfalls of extracting condensed tannins and other phenolics from plants: Insights from investigations onEucalyptus leaves

Optimal conditions for extraction of tannins and other phenolics from tree foliage and their subsequent storage rarely have been investigated. We investigated methods of drying leaves, optimal solvents, and the effects of light and temperature on the extractability and stability of condensed tannins (proanthocyanidins) and total phenolics from leaves ofEucalyptus trees. Aqueous acetone was a better solvent than aqueous methanol for condensed tannins and total phenolics, but condensed tannins were less stable in aqueous acetone than aqueous methanol. Stability of condensed tannins also was decreased substantially by room temperature versus 4°C and by exposure to indirect sunlight, although the assay for total phenolics was unaffected. For quantitative estimation of condensed tannins, extraction with 50% acetone was better than methods of direct analysis of leaf tissue. The highest estimates of total condensed tannins were obtained by exhaustive extraction with 50% acetone followed by direct analysis of the residue. Lyophilization of fresh leaf increased yield of condensed tannin (although usually by less than 10%). Lyophilization and subsequent storage of extracts had little effect on assays for condensed tannins or total phenolics.     

Innovative and intensified technology for the biological pretreatment of agro waste for ethanol production

Lignocellulosic biomass is an abundant, renewable resource, but the structural and chemical complexity of biomass acts as a hindrance in its effective utilization for cellulosic ethanol production. Hence, effective pretreatment is always necessary to remove the surrounding matrix of lignin prior to the enzymatic hydrolysis. Pretreatment of rice straw by Pleurotus florida was found to be effective and resulted in 49% lignin degradation, whereas fungus along with grape leaves resulted in 99% lignin degradation. This method not only explores a pathway for utilizing the solid agro waste but also results in a value-added product of edible mushrooms that has proved to be the best pretreatment technology for ethanol production. FTIR and SEM analysis confirmed the structural transformation taking place during the pretreatment. The components of grape leaves were also analyzed using GC-MS.     

Tannin Composition Affects the Oxidative Activities of Tree Leaves

We examined whether tannin composition plays an important role in explaining the oxidative activities of tree leaves of Acer saccharum (sugar maple) and Quercus rubra (red oak). Sugar maple leaves contained substantial amounts of ellagitannins, condensed tannins, and galloyl glucoses, whereas red oak leaves contained almost exclusively condensed tannins. Oxidative activities of the crude phenolics from both species, and the phenolic fractions from sugar maple, were measured with electron paramagnetic resonance (EPR) spectrometry and UV-visible spectrophotometry. The two assays produced similar results: (1) sugar maple phenolics produced larger semiquinone radical concentrations,and higher semiquinone decay rates and browning rates than did red oak phenolics;(2) ellagitannin levels were positively associated with the three measures of oxidative activity; and (3) condensed tannin and galloyl glucose levels were negatively associated with these measures. The negative relationship between condensed tannin levels and oxidative activity resulted from the antioxidant effects of condensed tannins on hydrolyzable tannins; several purified condensed tannins significantly decreased the concentrations of semiquinone radicals and browning rates of pedunculagin (an ellagitannin) and pentagalloyl glucose. As expected, whole-leaf extracts from sugar maple produced elevated levels of semiquinone radicals, but none were observed in red oak extracts when the two species were compared with an EPR time-course assay. We conclude that the oxidative activities of tree leaves may be affected by tannin composition, and that the prooxidant activity of ellagitannins may be decreased by co-occurring condensed tannins.     

巨尾桉单宁的纯化工艺及其抗氧化抑菌性能

利用NKA-9大孔树脂纯化了巨尾桉树皮和树叶中的单宁,并采用二苯基苦基肼自由基(DPPH·)和羟基自由基(·OH)的清除作用评价了其抗氧化性,采用滤纸片扩散法测定了其对5种常见食源性致病菌的抑菌作用。结果表明,在上样质量浓度0.8 g/L、上样量10 mL、体积分数80%乙醇解吸液用量为3倍柱体积(BV)的动态纯化条件下,树皮单宁纯化物中单宁的质量分数为47.82%;在上样质量浓度0.5g/L、上样量10mL、体积分数80%解吸液用量3BV的动态纯化条件下,树叶单宁纯化物中单宁的质量分数为37.00%。树皮和树叶中单宁纯化物对DPPH·的半抑制浓度(IC50)分别为0.0121和0.0168g/L;当单宁质量浓度为0.6 g/L时,对·OH的清除作用相当于V_C的2.55和2.19倍。树皮和树叶中单宁纯化物对大肠杆菌、金黄色葡萄球菌、痢疾杆菌、沙门氏菌、蜡状芽孢杆菌的抑制作用均强于粗提物,且对痢疾杆菌的抑菌圈直径分别达13.25、12.50 mm。     

Decomposition and nutrient release from pruning residues of two indigenous agroforestry species during the wet and dry seasons

The decomposition of leaves from Cordia africana Lam. and Albizia gummifera G. F.Gmel was investigated during the wet and dry seasons at Wondo Genet (Ethiopia). Litterbags of leaves were buried in soils under farmland and shaded-coffee agroforestry systems. Residual matter was recovered after 4, 8, 12, and 16 weeks and analysed for nitrogen (N), phosphorus (P), potassium (K), cellulose, lignin, soluble polyphenol and condensed tannin content. Mass-loss and release of N, polyphenols and condensed tannins were greater from Albizia leaves than from Cordia leaves, suggesting that a high polyphenol content does not necessarily retard decomposition. The rates of mass loss and release of the majority of leaf constituents were considerably faster during the wet season than during the dry season. Lignin decomposition, however, proceeded more rapidly during the dry season, and no significant seasonal differences were observed for polyphenol decomposition. The decomposition kinetics of most leaf components during the wet season were best described by a single-exponential model, but a quadratic model provided the best fit during the dry season. Initial leaf chemistry and season were important decomposition factors, while land-use effects were negligible. However, land-use effects showed distinct seasonal differences, with leaf litter decomposing more rapidly in soil under shaded-coffee than under farmland management, especially during the wet season. This study also demonstrated that polyphenol content does not show the predictive effects it has been attributed to have and that other constituents, such as condensed tannins, would be better suited for this purpose.