苎麻叶中绿原酸的分光光度法测定

探讨了采用分光光度法测定苎麻叶中绿原酸的含量的方法。12.5%的醋酸用量为0.1mL,7%尿素2.0mL,0.5%亚硝酸钠0.25mL,3min后加入5%氢氧化钠0.5mL,绿原酸与试剂形成鲜红色络合物,通过在510nm处测定溶液的吸光度确定绿原酸的含量。绿原酸浓度在0.01~0.12g/L范围内与吸光度值有良好的线性关系,回收率为95%~107%,相对标准偏差(RSD)为2.4%。该方法简便、快速。     

HPLC quantification of flavonoids and biflavonoids inCupressaceae leaves

Summary The aim of this investigation was to obtain qualitative and quantitative profiles of the flavonoid and biflavonoid composition of six cypress species—Cupressus funebris L.,Cupressus sempervirens L.,Cupressus glabra L.,Cupressus arizonica L.,Cupressus goveniana L., andCupressus lusitanica L. HPLC-diode-array detection (DAD), HPLC-MS, and HPTLC were used to identify the individual compounds. A chromatographic method was optimized for identification and quantification of the main flavonoid glycosides and biflavonoids. The flavonoids identified and calibrated were: rutin, quercetin glucoside, quercetin rhamnoside, and kaempferol 3-O-rhamnoside. The biflavonoids identified and calibrated were: cupressuflavone, amentoflavone, robustaflavone, hinokiflavone, methylrobustaflavone, methylamentoflavone, and dimethylcupressuflavone.     

盐酸浸提-电感耦合等离子体发射光谱法测定烟草中的多元素

研究了用5mol/L盐酸煮沸提取烟叶中的部分金属元素，用ICP－AES测定浸提液，K、Ca、Mg、Cu、B、Ba、Zn获得了较满意的结果，P、Fe、Mn的测定结果稍微偏低。此方法操作简便、快速安全，特别适合大批量烟草样的快速检测。与硝酸－高氯酸湿消化法进行对照，结果吻合得较好。并测定了国家烟草标准样品GBW08514和GBW08515，其结果与标准值相符。     

一种基于分子信标荧光探针快速检测烟草花叶病毒的新方法

研究了一种利用新型荧光探针——分子信标进行植物病毒检测的方法，可以不要求对病毒RNA进行严格的分离和纯化，就能快捷地得到检测结果。此方法被用于烟草花叶病毒(tobacco mosaic virus，TMV)基因组RNA的检测，为植物病毒分子生物学的研究提供了新的手段。     

Improved Extraction Method and Chromatographic Separation of Ginsenosides from Ginseng Roots,Leaves and Ginseng Drug Preparations

A new extraction method for ginsenosides from ginseng roots, ginseng leaves and ginseng drug preparations by Sep-Pak C₁₈ cartridges has been studied. Ginsenoside extraction by Sep-Pak cartridges is a rapid, efficient, reproducible method. In addition, the extracts were analyzed by high performance thin layer chromatography (HPTLC) and reverse phase high performance liquid chromatography (HPLC). The major components of ginseng saponins were effectively separated using an ODS-120T column.     

Glycosidases of turnip leaf tissues

Four myrosinase (β-thioglucosidase EC. 3.2.3.1) and seven disaccharase (β-fructofuranosidase, EC. 3.2.1.26) isoenzymes were isolated from turnip leaves. The most active enzymes were isolated in pure form. Myrosinase and disaccharase mol wt was 62.0 × 10³ and 69.5 × 10³ dalton, respectively, on the basis of gel filtration on Sephadex G-200. Myrosinase pH profile showed high activity between pH 5 and 7 with the optimum at pH 5.5. The purified enzyme was heat-stable for 60 min at 30°C with only loss of 24% of activity. Its activity is strongly inhibited (100%) by Pb²⁺, Ba²⁺, Cu²⁺ and Ca²⁺ ions, and activated (70%) by EDTA at 0.04M. The pure enzyme failed to hydrolyze amylose, glycogen, lactose, maltose, and sucrose. TheK _m andV _max values of myrosinase using sinigrin as specific substrate was 0.045 mM and 2.5 U, respectively. The maximal activity of disaccharase enzyme was obtained at pH 4–5 and 35–37°C. The enzyme was heat-stable at 30°C for 30 min with only 10% loss of its activity. Its activity is strongly activated (70–240%) by Ca²⁺, Ba²⁺, Cu²⁺, and EDTA at 0.01M. The enzyme activity is specific to the disaccharide sucrose and failed to hydrolyze other disaccharides (maltose and lactose). TheK _m andV _max of disaccharase were 0.123 mM and 3.33 U, respectively.     

烟草三维荧光特征和品质评吸的关系

研究不同品种烟草石油醚冷萃取物的三维荧光光谱，包括烟草所共在的荧光性质和各自的荧光特性，寻找它们与烟草香味，颈头等吃味之间的关系，选择合适的量值指标，为烟草品质的 观感官评估提供了一个实用的对照方法。     

The Biological Effects of Forsythia Leaves Containing the Cyclic AMP Phosphodiesterase 4 Inhibitor Phillyrin

Forsythia fruit (Forsythia suspensa Vahl (Oleaceae)) is a common component of Kampo medicines for treating the common cold, influenza, and allergies. The main polyphenolic compounds in the leaves of F. suspensa are pinoresinol β-d-glucoside, phillyrin and forsythiaside, and their levels are higher in the leaves of the plant than in the fruit. It is known that polyphenolic compounds stimulate lipid catabolism in the liver and suppress dyslipidemia, thereby attenuating diet-induced obesity and polyphenolic anti-oxidants might attenuate obesity in animals consuming high-fat diets. Recently, phillyrin was reported as a novel cyclic AMP phosphodiesterase 4 (PDE4) inhibitor derived from forsythia fruit. It was expected that the leaves of F. suspensa might display anti-obesity effects and serve as a health food material. In this review, we summarized our studies on the biological effects of forsythia leaves containing phillyrin and other polyphenolic compounds, particularly against obesity, atopic dermatitis, and influenza A virus infection, and its potential as a phytoestrogen.     

Direct electrochemistry of recombinant tobacco peroxidase on gold

Direct electron transfer (DET) reactions of recombinant tobacco peroxidase (rTOP), namely direct electroreduction of Compound I/Compound II and heme Fe^3+/2+ conversion, were studied on gold electrodes. rTOP of wild type, non-glycosylated, was produced using an Escherichia coli expression system. At pH 5.0, the redox potential for direct electrochemical transformation of the Fe^3+/2+ of the peroxidase heme was −143 mV vs. AgAgCl, and 0.26 ± 0.07 pmol of the adsorbed rTOP were in DET contact with the gold electrode. The total amount of the adsorbed rTOP estimated from QCM data was 53 ± 5 pmol/cm² or 1.67 pmol when referred to the surface area of the electrodes used for electrochemical measurements. Of 1.67 pmol of adsorbed rTOP, only 0.76 pmol were catalytically active. DET between Au and the enzyme was also studied in the reaction of the bioelectrocatalytic reduction of H₂O₂ by cyclic voltammetry and amperometric detection of H₂O₂ at +50 mV with rTOP-modified Au electrodes placed in a wall-jet flow-through electrochemical cell. Maximal bioelectrocatalytic current response of the rTOP-modified gold electrodes to H₂O₂ was observed at pH 5.0 and stemmed from its bioelectrocatalytic reduction based on DET between Au and the active site of rTOP. Kinetic analysis of the DET reactions gave 52% of the adsorbed rTOP molecules active in DET reactions (0.4 pmol of adsorbed catalytically active rTOP, correspondingly), which correlated well with the non-catalytic-voltammetry data. DET was characterised by a heterogeneous ET rate constant of 13.2 s⁻¹, if one takes into account the QCM data, and 19.6 s⁻¹, if the amount of rTOP estimated from the data on DET transformation of Fe^3+/2+ couple of rTOP is considered. The sensitivity for H₂O₂ obtained for the rTOP-modified Au electrodes was 0.7 ± 0.1 A M⁻¹ cm⁻². These are the first ever-reported data on DET reactions of anionic plant peroxidases on bare gold electrodes.