虎杖对植物病原真菌的杀菌活性及有效成分研究

植物源杀菌剂的开发应用以及从植物中寻找杀菌活性物质作为先导化合物，是目前杀菌研究领域的热点之一。本文以蓼科植物虎杖（Polygonum cuspidatum Sieb.et Zucc.) 为材料，研究了虎杖提取物的杀菌活性和作用机理，确定了虎杖中的有效杀菌活性成分，并以此为先导化合物进行了衍生物合成与结构活性关系的研究。 不同溶剂提取物制备与杀菌活性测定结果表明，乙醇适合作为虎杖植物杀菌剂的提取溶剂，提取率高，对多种植物病原真菌具有广谱的杀菌和抑菌活性，除对黄瓜白粉病（Sphaerotheca fuliginea）表现出很好的防治效果外，对苹果腐烂病菌（Valsa mali）、玉米小斑病菌（Helminthosporium maydis）、葡萄炭疽病菌（Colletotrichum gloeosporioides）、小麦赤霉病菌（Fusarium graminearum）、油菜菌核病菌（Sclerotinia sclerotiorum）、水稻纹枯病菌（Rhizoconia solani）等也具有很好的抑制作用。虎杖回流提取物对黄瓜白粉病的杀菌作用以保护作用为主，兼具一定的治疗作用，并且具有一定的内吸活性，持效期约为4-7 d。温室试验结果表明，虎杖乙醇回流提取物10%可溶性液剂对黄瓜白粉病的EC90值为172.83 mg/L，田间小区试验表明该制剂在800-1600 mg/L的浓度下，对黄瓜白粉病的防效达到76.3-93.4%，具有较好的应用前景。 对苹果腐烂病菌的抑菌作用机理表明，虎杖乙醇提取物对该病原菌有明显的抑制作用，能够抑制蛋白质、葡萄糖等菌体细胞内物质的合成，从而使病菌代谢速度减慢，抑制其生长。虎杖提取物还能够使几丁质酶和β-1,3葡聚糖酶这两种细胞壁相关水解酶的活性升高，降解细胞壁而破坏菌体结构，使菌体自溶。 过测定虎杖乙醇回流提取物对黄瓜体内等一些防御酶和病程相关蛋白活性的影响，表明在40 mg/L和400 mg/L浓度下，虎杖乙醇提取物能够使黄瓜叶片内的过氧化物酶（POD）、多酚氧化酶(PPO)、苯丙氨酸解氨酶(PAL)、几丁质酶等不同程度的升高，从而在一定程度上提高植物对病原真菌的抗病能力。 通过生物活性跟踪测定以及pH梯度提取法确定了虎杖中的主要杀菌活性成分为蒽醌类化合物大黄素（emodin）和大黄素甲醚（physcion），结构通过了HPLC-MS和1H NMR确认，并且通过HPLC确定了虎杖乙醇回流提取物中二者的含量分别为3.28%和1.11%。 以虎杖中的有效成份之一的大黄素为原料，通过羟基的甲基化反应合成了包括已知物大黄素甲醚在内的11个大黄素衍生物，其中5个化合物为首次报道，并进行了初步结构活性关系研究。结果表明通过对大黄素3-OH位置以短直链烷基取代，其衍生物对黄瓜白粉病的活性大大提高，其中以甲基取代的衍生物大黄素甲醚的活性为母体大黄素的16.7倍，而以取代苄基修饰的衍生物的活性没有明显提高。一些目标化合物的活性明显优于三唑酮。研究中还意外发现大黄素的甲基化衍生物三甲氧基大黄素在4000 mg/L时能够明显抑制甜菜夜蛾幼虫的取食与生长发育，而大黄素和大黄素甲醚则无此作用。

Qualitative and semi-quantitative analysis of quaternary alkaloids in Coptis-scute herb couple by Electrospray mass Spectrometry

A practical solution of qualitatively analyzing quaternary alkaloids in coptis-scute herb couple by electrospray ionization mass spectrometry(ESI-MS) was developed. Without the complicated pretreatment of sample, the active ingredients including berberine, palmatine, coptisine, jatrorrhizine, epiberberine, and columbamine were identified and some relative content changing rules of alkaloids in coptis-scute couple were summarized in this article. The overall profiles of the complex extracts were obtained.

Chinese herb medicines analyses by capillary electrophoresis with amperometric detection

Capillary electrophoresis (CE) with amperometric detection (AD) has been widely used in various fields of analytical science, especially in the pharmaceutical industry recently due to its high separation efficiency and low detection limit. The determination of active ingredients in Chinese herb medicines by CE-AD is of great importance in developing the researches on pharmacology of herbs, quantitative analysis and quality control. Analyses of the effective components in Chinese herb medicines and compound Chinese herb medicine by CE-AD are reviewed in this paper. In contrast with other analysis methods, the advantage of CE-AD is discussed. The development in analyses of traditional Chinese medicine (TCM) by CE-AD in future is mentioned.

毛细管电泳安培检测法在中草药分析中的应用

Capillary electrophoresis (CE) with amperometric detection (AD) has been widely used in various fields of analytical science, especially in the pharmaceutical industry recently due to its high separation efficiency and low detection limit. The determination of active ingredients in Chinese herb medicines by CE-AD is of great importance in developing the researches on pharmacology of herbs, quantitative analysis and quality control. Analyses of the effective components in Chinese herb medicines and compound Chinese herb medicine by CE-AD are reviewed in this paper. In contrast with other analysis methods, the advantage of CE-AD is discussed. The development in analyses of traditional Chinese medicine (TCM) by CE-AD in future is mentioned.

Analysis of five pharmacologically active compounds from the Tibetan medicine Elsholtzia with micellar electrokinetic capillary chromatography

A high performance capillary electrophoresis method with diode array detector detection for the determination of five bioactive ingredients in Tibetan medicine Elsholtzia, namely quercetin, rutin, saussurenoside, kaempferol, and oleanolic acid, has been developed. The effects of several factors, such as the acidity, concentration of running buffer, separation voltage, temperature, and SDS concentration were investigated. The optimal conditions were 44 mmol/L boric acid running buffer (pH 8.5), 45 mmol/L SDS, 16 KV voltage, 20 degrees C, and 10.0% (V/V) of acetonitrile. Under the optimum conditions, five components could be separated with a good baseline resolution within 17 min. The calibration curves showed good linear relationship over the concentration range of 5 x 10(-4)similar to 0.1 mg/mL for quercetin, rutin, saussurenoside, kaempferol, and 1 x 10(-3) similar to 0.1 mg/mL for oleanolic acid. The average recoveries of the method and RSD were ( 99.2%, 3.2%) for quercetin, (102.1%, 2.1%) for rutin, (99.4%, 1.5%) for saussurenoside, (98.9%, 1.8%) for kaempferol, and (99.0%, 2.9%) for oleanolic acid, respectively. The detection limits (S/N = 3) were 1.1 x 10(-4) mg/mL for quercetin, 2.6 x 10(-4) mg/mL for rutin, 1.8 x 10(-4) mg/mL for saussurenoside, 2.9 x 10(-4) mg/mL for kaempferol, and 6.3 x 10(-4) mg/mL for oleanolic acid, respectively. The method was simple, rapid, and reproducible and could be applied for the determination of quercetin, rutin, saussurenoside, kaempferol, and oleanolic acid in Tibetan medicine Elsholtzia, and the assay results were satisfactory.

Energy conversions and storage caused by an unsteady poloidal flow in active solar regions

In this paper we discuss coupling processes between a magnetic field and an unsteady plasma motion, and analyze the features of energy storage and conversions in active region. It is pointed out that the static force-free field is insufficient for a discussion of storage processes, and also the pure unsteady plasma rotation is not a perfect approach. In order to analyze the energy storage, we must consider the addition of poloidal plasma motion. The paper shows that because the unsteady poloidal flow is added and coupling occurs between the magnetic field and both the toroidal and the poloidal plasma flows, an unsteady process is maintained which changes the force-free factor with time. Hence, the energy in the lower levels can be transferred to the upper levels, and a considerable energy can be stored in the active region. Finally, another storage process is given which is due to the pure poloidal flow. The article shows that even if there is no twisted magnetic line of force, the energy in the lower levels may still be transferred to the upper levels and stored there.

Explorations of electric-current system in solar active regions .1. Empirical inferences of the current flows

In this paper we explore techniques to identify sources of electric current systems and their channels of flow in solar active regions. Measured photospheric vector magnetic fields (VMF) together with high-resolution white-light and H filtergrams provide the data base to derive the current systems in the photosphere and chromosphere. Simple mathematical constructions of fields and currents are also adopted to understand these data. As an example, the techniques are then applied to infer current systems in AR 2372 in early April 1980. The main results are: (i) In unipolar sunspots the current density may reach values of 103 CGSE, and the Lorentz force on it can accelerate the Evershed flow, (ii) Spots exhibiting significant spiral pattrn in the penumbral filaments are the sources of vertical major currents at the photospheric surface, (iii) Magnetic neutral lines where the transverse field was strongly sheared were channels along which strong current system flows, (iv) The inferred current systems produced oppositely-flowing currents in the area of the delta configuration that was the site of flaring in AR 2372.

Active phase control and frequency chirp effects on supercontinuum generation in high birefringence photonic crystal fiber

An acoustic-optics programmable dispersive filter (AOPDF) was first employed to actively control the linearly polarized femtosecond pump pulse frequency chirp for supercontinuum (SC) generation in a high birefringence photonic crystal fiber (PCF). By accurately controlling the second order phase distortion and polarization direction of incident pulses, the output SC spectrum can be tuned to various spectral energy distributions and bandwidths. The pump pulse energy and bandwidth are preserved in our experiment. It is found that SC with broader bandwidth can be generated with positive chirped pump pulses except when the chirp value is larger than the optimal value, and the same optimal value exists for the pump pulses polarized along the two principal axes. With optimal positive chirp, more than 78% of the pump energy can be transferred to below 750 nm. Otherwise, negative chirp will weaken the blue-shift broadening and the SC bandwidth. (C) 2007 Elsevier B.V. All rights reserved.

Stabilization of optical Fabry-Perot sensor by active feedback control of diode laser

This paper presents the design and characterization of a fiber Fabry-Perot interferometer (FFPI) acoustic wave detector with its Q point being stabilized actively. The relationship between the reflectivity of the F-P cavity facets and cavity length was theoretically analyzed, and high visibility of 100% was realized by optimized design of the F-P cavity. To prevent the drifting of the Q point, a new stabilization method by actively feedback controlling of the diode laser is proposed and demonstrated, indicating the method is simple and easy operating. Measurement shows that good tracing of Q point was effectively realized. (c) 2008 Elsevier B.V. All rights reserved.

A planar waveguide Nd : YAG laser using active Q-switching of a hybrid unstable resonator

A planar waveguide laser operating in a negative branch unstable resonator is Q-switched by an acoustooptic mod latorin anew configuration, providing effective, high-speed switching. The laser using a 200-mu m Nd:YAG core, face pumped by 10 laser diode bars, has produced 100-W output in a good beam quality at 100-kHz pulse rate, and 4.5 mJ at lower frequency with 15-ns pulse duration.