Determination of Quercetin in Extracts of Ginkgo biloba L. Leaves by Near‐Infrared Reflectance Spectroscopy Based on Interval Partial Least‐Squares (iPLS) Model

Abstract

This paper developed a multivariate method of analysis of quercetin in Ginkgo biloba leaf extracts, based on reflectance NIR measurements and partial least squares regression. In order to give a better correlation with the results obtained by HPLC, multiplicative scatter correction (MSC) was utilized to correct scattering effect and interval partial least squares (iPLS) to select optimum wavelength region. In general, good calibration statistics were obtained for the prediction of quercetin content, as demonstrated by some figures of merit, namely linearity, repeatability, and accuracy. And the iPLS model was more reliable than the full model.     

外源性加硒法增加枣中硒含量的研究

以不同深度硒溶液对枣树进行不同次数的叶面喷施,得到了不同硒含量的枣样品,用荧光光度法测定了样品中硒的含量。结果表明,与对照组相比,用外源性加硒法可明显提高枣中硒的含量;并且可通过调节喷施液浓度和喷施次数,得到硒含量适宜的成熟小枣。     

毛细管电泳法测定桑叶中的黄酮类成分──芦丁和槲皮素

 采用高效毛细管电泳法分离测定了新疆不同地区、不同采集期、不同品种的桑叶中的黄酮类成分芦丁、槲皮素的含量。以含有体积分数为 15 %甲醇的 10mmol/L的磷酸二氢钠 2 0mmol/L的硼砂溶液 (pH 8 6 2 )为电泳缓冲液 ,采用压力进样方式 ,在 2 5℃ ,2 0kV恒压下进行电泳分离 ,并在 2 45nm波长处检测。结果表明 ,桑叶中的两种目标组分在 12min内完全分离 ,且有良好的线性关系 ;芦丁和槲皮素的加样回收率分别为 95 6 4%和99 36 % ,其RSD分别为 2 2 5 %和 1 79% (n =6 )。方法简单、准确、快速。     

Effect of sunlight on the preparation and properties of cellulose/silver nanoparticle composite films by in situ method using Ocimum sanctum leaf extract as a reducing agent

Cellulose/silver nanoparticle composite films with in situ-generated silver nanoparticles (AgNPs) were prepared using Ocimum sanctum leaf extract as a reducing agent in the absence and presence of sunlight and were characterized by SEM, FTIR, XRD, and antibacterial tests. Sunlight hastened up the preparation of these composite films. The average size of the in situ-generated AgNPs was reduced by the sunlight. The antibacterial activity and other properties of the composites were enhanced by the sunlight. The cellulose/AgNP composite films with improved properties by sunlight can be considered for medical purpose as antibacterial dressing materials.     

Acute and sub-acute toxicological evaluation of the alcoholic leaf and root extracts of Clerodendrum infortunatum L.

Leaf and root extracts of Clerodendrum infortunatum L. have been reported to show anthelmintic efficacy on a cestode parasite Raillietina tetragona. Its leaf showed no toxicity at 1000 mg/kg body weight but root toxicity study was not known. Therefore, our study is to test both leaf and root extracts at 2000 and 3000 mg/kg body weight concentration given orally for 15 days in four groups of Swiss albino mice, keeping another set as control (without plant extract). Weight and behaviour of mice were recorded daily. Feeding, movement pattern were normal in all treatments as that of control. Though body weight increase, there was no change in the relative organ weight. Biochemical and haematological studies revealed no significant change from control and no alteration in histopathological study of liver and kidney from that of control. The plant extracts thus shown to be safe for consumption.     

竹叶提取物对铝在HCl溶液中的缓蚀作用

用不同浓度的C₂H₅OH（体积分数：20%-80%）从金竹竹叶中提取制备出竹叶缓蚀剂（简称为PSLE）,用紫外-可见（UV-Vis）光谱和傅里叶变换红外（FTIR）光谱对其进行了表征,并对总黄酮含量进行了测定. 采用失重法、动电位极化曲线、电化学阻抗谱（EIS）和扫描电子显微镜（SEM）研究PSLE在HCl 介质中对铝的缓蚀作用.采用量子化学密度泛函理论（DFT）研究了两个主要竹叶黄酮成分牡荆苷和异牡荆苷的吸附方式. 结果表明：PSLE对铝具有良好的缓蚀作用,且在铝表面的吸附符合Langmuir 吸附等温式. 缓蚀率随其浓度的增加而增大,但随温度的升高和盐酸浓度的增加而降低. 竹叶总黄酮含量和竹叶缓蚀剂的缓蚀性能有良好的相关性,初步推测竹叶缓蚀剂的有效成分主要为竹叶黄酮类化合物. PSLE为阴极抑制型缓蚀剂;EIS 在高频区呈容抗弧,在低频区呈感抗弧,添加PSLE后,阻抗值显著增大. SEM表明添加PSLE对铝的腐蚀产生了明显的抑制作用.量子化学计算结果表明,牡荆苷和异牡荆苷的吸附中心主要集中在竹叶黄酮骨架（FBS）.     

Determination of the insecticide fenoxycarb in apple leaf samples by an enzyme-linked immunosorbent assay

An enzyme-linked immunosorbent assay (ELISA) was used for the determination of fenoxycarb in apple leaf samples. Single step extraction procedures with phosphate-citrate buffered solution containing different amounts of methanol were tested showing that a solvent percentage of 20% (v/v) was the best condition, with recoveries between 85 and 100% in the working range of 25-500 μg kg⁻¹ and a negligible matrix effect. The low detection limit reached, 1 μg kg⁻¹ against 50 μg kg⁻¹ for the recommended liquid chromatographic method, makes the ELISA more suitable for determinations of the fenoxycarb residues in apple leaf samples. The reliability of the ELISA was evaluated by assaying the insecticide in spiked and contaminated samples by three different approaches: direct determination, standard addition method with a calibration graph, and the dilution test. The corresponding coefficients of variation were, respectively, 11, 22 and 27%. The direct determination on the (1+1) diluted apple leaf extract was used to measure the insecticide residues in samples collected in the north-eastern Italian regions of Veneto and Trentino-Alto Adige.     

Straightforward Preparation of (2E,4Z)-2,4-Heptadien-1-ol and (2E,4Z)-2,4-Heptadienal

Abstract

A concise synthesis of (2E,4Z)-2,4-heptadien-1-ol and (2E,4Z)-2,4-heptadienal is presented. Commercially available (Z)-2-penten-1-ol was converted to ethyl-(2E,4Z)-2,4-heptadienoate by reaction with activated MnO₂ and (carboethoxymethylene)triphenylphosphorane in the presence of benzoic acid as a catalyst. Ethyl-(2E,4Z)-2,4-heptadienoate was converted to (2E,4Z)-2,4-heptadien-1-ol with LiAlH₄. The alcohol was partially oxidized to (2E,4Z)-2,4-heptadienal with MnO₂. The title compounds are male-specific, antennally active volatile compounds from the Saltcedar leaf beetle, Diorhabda elongata Brulle (Coleoptera: Chrysomelidae) and have potential use in the biological control of the invasive weed saltcedar (Tamarix spp).     

微量元素叶面肥料中硼的测定

研究了在 pH 6 .5乙酸铵缓冲溶液中 ,硼与 3 甲氧基 甲亚胺H的显色反应条件 ,最大吸收在 4 2 0nm处 ,摩尔吸光系数为 8.1× 10 3,硼含量在 0～ 10 μg/ 10ml范围内符合比耳定律。用于微量元素叶面肥料中硼的测定 ,获得了与国标法一致的结果     

青海柴达木地区植物白刺叶中微量元素特征

青海柴达木地区分布有丰富的白刺植物资源。利用220FS原子吸收光谱仪分析了该地区三种白刺叶片的Cu,Zn,Fe,Mn,Cr,Ni,Cd等微量元素。结果表明，铬、 锰含量显著提高是青海柴达木地区植物白刺叶资源微量元素特征。这为柴达木地区白刺叶资源的开发利用提供科学依据。