基于近红外光谱与误差反向传播神经网络技术的三种人工林木材识别研究

利用近红外光谱结合误差反向传播神经网络(BP)对三种人工林木材(尾叶桉、马尾松、南方无性系I-72杨)进行识别,探讨隐含层神经元个数、光谱预处理方法、光谱范围对BP网络模型的影响,并与SIMCA法所建模型做比较。结果表明：(1)BP网络结合全波段(780～2 500 nm)近红外光谱数据建模,识别正确率达到97.78%,并确定隐含层神经元数为13;(2)全波段光谱建模比短波段(780～1 100 nm)和长波段(1 100～2 500 nm)光谱建模识别效果好,其识别正确率分别为97.78%, 95.56%和96.67%,用一阶导数和二阶导数对全波段光谱进行预处理后,BP网络模型识别正确率分别为93.33%和71.11%;用多元散射校正(MSC)对全波段光谱进行预处理后,BP网络模型识别正确率为98.89%,(3)在三种波段(780～2 500,780～1 100和1 100～2 500 nm)光谱建模的情况下,BP网络建模识别正确率分别为95.56%, 96.67%和97.78%,SIMCA模型识别正确率分别为76.67%, 81.11%和82.22%,BP网络建模比SIMCA法建模对三种人工林木材的识别正确率高。     

Growth Restriction of Rhizoctonia solani via Breakage of Intracellular Organelles Using Crude Extracts of Gallnut and Clove

Plant diseases reduce crop yield and quality, hampering the development of agriculture. Fungicides, which restrict chemical synthesis in fungi, are the strongest controls for plant diseases. However, the harmful effects on the environment due to continued and uncontrolled utilization of fungicides have become a major challenge in recent years. Plant-sourced fungicides are a class of plant antibacterial substances or compounds that induce plant defenses. They can kill or inhibit the growth of target pathogens efficiently with no or low toxicity, they degrade readily, and do not prompt development of resistance, which has led to their widespread use. In this study, the growth inhibition effect of 24 plant-sourced ethanol extracts on rice sprigs was studied. Ethanol extract of gallnuts and cloves inhibited the growth of bacteria by up to 100%. Indoor toxicity measurement results showed that the gallnut and glove constituents inhibition reached 39.23 μg/mL and 18.82 μg/mL, respectively. Extract treated rice sprigs were dry and wrinkled. Gallnut caused intracellular swelling and breakage of mitochondria, disintegration of nuclei, aggregation of protoplasts, and complete degradation of organelles in hyphae and aggregation of cellular contents. Protection of Rhizoctonia solani viability reached 46.8% for gallnut and 37.88% for clove in water emulsions of 1000 μg/mL gallnut and clove in the presence of 0.1% Tween 80. The protection by gallnut was significantly stronger than that of clove. The data could inform the choice of plant-sourced fungicides for the comprehensive treatment of rice sprig disease. The studied extract effectively protected rice sprigs and could be a suitable alternative to commercially available chemical fungicides. Further optimized field trials are needed to effectively sterilize rice paddies.     

Identification of Pulsatilla chinensis (Bge.) Regel and look-alike species by UHPLC-TOF-MS using multivariate statistical analysis

Pulsatillae Radix, the root of Pulsatilla chinensis (Bge.) Regel, is recorded in the Pharmacopoeia of the People's Republic of China and has been widely used for its pharmacological activities, such as anti-inflammatory, antioxidant, antibacterial, antitumor, and cardiovascular benefits. However, there are several look-alike species that can be marketed as Pulsatillae Radix. To distinguish P. chinensis (Bge.) Regel from its look-alikes, viz. Pulsatilla cernua (Thunb.) Bercht et Opiz., Pulsatilla dahurica (Fisch.) Spreng., Anemone tomeutosa (Maxim.) Pei., and Rhaponticum uniflorum (L.) DC, we used ultra high performance liquid chromatography with time-of-flight mass spectrometry combined with principal component analysis to compare their chemical compositions. Four ions, a (RT 8.98 min, m/z 1381.6671), b (RT 10.64 min, m/z 1219.6143), c (RT 11.52 min, m/z 1217.5978), and d (RT 13.6 min, m/z 749.4463), from P. chinensis (Bge.) Regel were identified as potential chemical markers to distinguish it from look-alike species using an unsupervised statistical model combined with orthogonal partial least-squares discriminant analysis. The results of this study provide an effective method for identifying and distinguishing P. chinensis (Bge.) Regel from similar plants.     

微量热法研究黄连及其主要组分配伍的抑菌作用

基于微量热法,研究黄连、黄连的主要组分小檗碱、药根碱、巴马汀及其配伍模拟方的抑菌作用.以HPLC法测定黄连中小檗碱、药根碱和巴马汀的含量,并根据其含量比值配伍模拟方;微量热法测定黄连、小檗碱、药根碱、巴马汀及其模拟方对痢疾杆菌的生长代谢曲线,得出相应的热动力学参数,并进行对应分析.结果表明黄连、小檗碱、药根碱、巴马汀及其模拟方对痢疾杆菌的生长代谢均有不同程度的抑制作用,黄连作用最强,单体生物碱作用弱,配伍模拟方作用增强,但并未显现明显协同作用,黄连的抑菌作用可能为多种活性成分的综合作用.     

微波辅助提取壶瓶枣多糖及其抗氧化性

采用微波辅助法提取了壶瓶枣多糖,并对壶瓶枣粗多糖(CP)、脱蛋白多糖(DP)对·OH、O-2·和DPPH·3种自由基的清除作用进行了研究.结果表明:壶瓶枣CP和DP对3种自由基都有明显的清除作用,清除率与多糖浓度存在明显的量效关系.壶瓶枣CP和DP对·OH、O-2·和DPPH·的半清除率(IC50)值分别为0.2312、0.9326、0.1830mg/mL和0.5049、0.2016、0.0694mg/mL.CP清除能力为DPPH·＞· OH＞O-2·,DP清除能力为DPPH· ＞O-2·＞·OH.     

Controlled acid hydrolysis and kinetics of flavone C-glycosides from trollflowers

Acid hydrolysis mechanisms of orientin-2"-O-galactopyranoside(OGA),orientin and other flavone C-glycosides in the trollflowers[Trollius chinensis Bunge) were studied in this report for the first time.Hydrolysis parameters including temperature,acidity,solvent and reaction time were comprehensively investigated.OGA could be hydrolyzed to orientin,followed by an isomerization to isoorientin via a reversible Wessely-Moser rearrangement reaction under stronger acidic conditions.A first-order kinetic model fitted the hydrolysis process of OGA well.Under the optimal hydrolysis conditions of 80 ℃,1.0 mol/L H~+ and 7 h reaction time,about 77%OGA was transformed to orientin with no detectable isoorientin.These results could be helpful for better understanding of the acid hydrolysis kinetics of flavone C-glycosides,as well as the preparation of these valuable components under controlled acid hydrolysis conditions.     

Two Unusual Rearranged Flavan Derivatives from Narcissus tazetta var. chinensis

Two unusual rearranged flavan derivatives with a rare bicyclo[3.3.1]non‐3‐ene‐2,9‐dione ring, tazettone A ( 1 ) and tazettone B ( 2 ), together with five known flavans, 3 – 7 , were isolated from the bulbs of Narcissus tazetta var. chinensis Roem . The structures of two new compounds were elucidated by spectroscopic analyses, including 1D‐ and 2D‐NMR spectroscopy. All of the isolated compounds were evaluated for their cytotoxicities against four human tumor cell lines A549, HCT116, SK‐BR‐3, and HepG2. Compounds 1 and 2 were almost inactive against all tested cell lines, while compounds 3 – 7 exhibited moderate or weak cytotoxicities against the tested cell lines.     

Metabolomics Analysis of Litchi Leaves during Floral Induction Reveals Metabolic Improvement by Stem Girdling

Prolonged exposure to cold temperatures often results in a relatively low flowering rate in litchi (Litchi chinensis Sonn.) trees with younger leaves. This study aimed to verify the impact of stem girdling on litchi flowering by identifying and characterizing the induced metabolic changes. After a 60 day exposure to cold treatment at 15 °C/10 °C (12 h/12 h), the flowering rate of the girdled trees was 100%, while that of the non-girdled trees was 20%, indicating that girdling improved litchi flowering at its turning stage. The metabolic profiles of litchi leaves with and without stem girdling during floral induction were compared and 505 metabolites potentially associated with litchi flowering were detected. Most metabolites were involved in the metabolism of starch and sucrose, fatty acid, and phenylpyruvic acid. The metabolic pathways concerned with the biosynthesis of epinephrine, sucrose, and d-maltose were induced in leaves after girdling treatment. The level of galactitol, phenylpyruvic acid, acetyl-CoA, linoleic acid, alpha-linolenic acid, and 13-HPOT biosynthesis remained stable in the leaves from girdled trees but changed drastically in the leaves from non-girdled trees. In addition, 379 metabolites concerning flowering rate were characterized. Metabolism pathways of starch and sucrose, galactose, and linoleic acid are of great significance to the flowering of litchi. Linoleic acid exhibited the most significant variations between girdled trees and non-girdled trees with fold changes of up to 13.62. These results contribute to understanding the biological mechanism of litchi floral induction and the metabolic changes after stem girdling.     

A new pyrrolidone derivative from Pistacia chinensis

A new N-phenyl-pyrrolidone derivative had been isolated from Pistacia chinesis Bunge. Its structure was elucidated as 4-hydroxy-5-（2-oxo-1-pyrrolidinyl）-benzoic acid, named pistaciamide on the basis of the 1D-NMR, DEPT, HMQC and HMBC spectroscopic techniques. 2007 Xi Kui Liu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.