Two homosecoiridoids from the fl ower buds of Lonicera japonica

Two new homosecoiridoids, named loniaceticiridoside (1) and lonimalondialiridoside (2), were isolated from an aqueous extract of the flower buds of Lonicera japonica. Their structures including the absolute configuration were determined by extensive spectroscopic studies, especially by 2D NMR and CD data analysis. A proposed biosynthetic pathway and preliminary investigations of the biological activity of compounds 1 and 2 are also discussed.     

氮肥对结缕草种子生产影响的研究

通过研究不同氮肥用量对二年生结缕草种子产量的影响,初步结果表明:结缕草的草高随着施氮量的增加而增高,草高与施氮量间存在极显著的正线性关系.当氮肥用量为8g/m2时,结缕草单位面积穗数、穗粒数最多,结缕草种子产量也最高,达到761kg/hm2,发芽率为96%.     

日本林蛙部分生理生化指标的比较

本文介绍我们对日本林蛙(Rana j.japonica)在冬眠期(12～2月,5.5～8.5℃)与活动期(9～11月,12.5～24℃)的部分生理生化指标的比较.测定了血清、肝、脑、心肌和骨骼肌的乳酸脱氢酶(LDH)同工酶的相对活力(±SD)、血红蛋白浓度及红细胞数等指标.这些指标不仅存在明显的组织差异,也存在季节差异和种群差异.     

Chemical Constituents from the Stems of Mahonia Japonica

A new dihydroberberine alkaloid, 7,8‐dihydro‐8‐methoxyberberine ( 1 ), along with six known compounds including two dihydroberberine alkaloids, 7,8‐dihydro‐8‐hydroxyberberine ( 2 ) and oxyberberine ( 3 ) and four protoberberine alkaloids, berberine ( 4 ), palmatine ( 5 ), jatrorrhizine ( 6 ) and columbamine ( 7 ), were isolated from the stems of Mahonia japonica. These compounds were characterized and identified by physical and spectral evidence.     

Nonalkaloid Constituents from Stemona japonica

Five new nonalkaloid constituents, a neolignan, japonin A ( 1 ), a macrocyclic lactone, japonin B ( 2 ), a (phenylethyl)benzoquinone, japonin C ( 3 ), a phenanthraquinone, japonin D ( 4 ), as well as a dihydrostilbene, stilbostemin M ( 5 ), were isolated from the roots of Stemona japonica, together with eight known compounds. Their structures were established by spectroscopic analyses.     

不同光照水平下白酒草 (Conyza japonica)氮、镁元素的分配

对多年生草本植物白酒草在高、中、低3个光照水平下，氮和镁在根、茎、叶中的分配进行了研究．结果表明：光照水平显著的影响了白酒草对叶和根的氮和镁的分配，而对于氮和镁在茎中的分配没有显著影响．高光照水平下，更多的氮和镁被分配到根中．低光照水平下．白酒草将较多的氮和镁分配至叶中．不同光照水平下白酒草氮镁分配方式和生物量分配方式的相似性说明．在氮和镁的分配利用上，植物也存在功能平衡作用．是植物生长和光合作用反馈调节的结果．     

漆姑草挥发油化学成分的研究

采用水蒸气蒸馏方法提取漆姑草挥发油,测得漆姑草挥发油的含量为0.08%;利用GC-MS联用技术从漆姑草挥发油中分离并鉴定出28种化学成分,占总挥发油的69.635%;用峰面积归一化法通过化学工作站数据处理系统得出各化学成分在挥发油中的相对百分含量。方法稳定可靠,为开发及综合利用漆姑草提供科学依据。     

日本柳杉合理经营密度的研究

通过对鄂西南日本柳杉人工林调查，用数理统计原理，选择6种方程建立冠幅面积与胸径间的相关数学模型，求得最佳数学模型为：Cw=0．657492 0．439685D，由此得到冠幅面积预测方程及不同胸径的理论密度，最后，依所测定的树冠重叠系数(K=1.26)求得林分最大密度，并计算了经营密度0．6～0．8的日本柳杉人工林林分密度，以便于生产上对日本柳杉人工林林分密度进行管理．     

从海带根中提取纯化褐藻硫酸多糖

海带根粉碎后，经过酶解，去除褐藻酸，得到酶解液；通过DE-41、DE-80离子交换柱层析，得到海带硫酸多糖(FGS)F1-F8的8种不同组分；再用Sepharose 2B凝胶柱层析纯化，获得层析纯F1-F8的FGS．我们初步测定了8种FGS的分子量、单糖组分及其摩尔比．FGS为一类含有鼠李糖、岩藻糖、木糖、甘露糖、半乳糖以及硫酸根的杂多糖．     

Mass‐spectrometry‐directed analysis and purification of pyrrolizidine alkaloid cis/trans isomers in Gynura japonica

Pyrrolizidine alkaloids are highly hepatotoxic natural chemicals that produce irreversible chronic and acute hepatotoxic effects on human beings. Purification of large amounts of pyrrolizidine alkaloids is necessary for toxicity studies. In this study, an efficient method for targeted analysis and purification of pyrrolizidine alkaloid cis/trans isomers from herbal materials was developed for the first time. Targeted analysis of the hepatotoxic pyrrolizidine alkaloids was performed by liquid chromatography with tandem mass spectrometry (precursor ion scan and daughter ion scan), and the purification of pyrrolizidine alkaloids was achieved with a mass‐directed auto purification system. The extraction and preparative liquid chromatography conditions were optimized. The developed method was applied to analysis of Gynura japonica (Thunb.) Juel., a herbal medicine traditionally used for detumescence and relieving pain but is potentially hepatotoxic as it contains pyrrolizidine alkaloids. Twelve pyrrolizidine alkaloids (six cis/trans isomer pairs) were identified with reference compounds or characterized by liquid chromatography with tandem mass spectrometry, and five individual pyrrolizidine alkaloids, including (E)‐seneciphylline, seneciphylline, integerrimine, senecionine, and seneciphyllinine, were prepared from G. japonica roots with high efficiency. The results of this work provide a new technique for the preparation of large amounts of pyrrolizidine alkaloid reference substances, which will also benefit toxicological studies of pyrrolizidine alkaloids and treatments for pyrrolizidine alkaloid‐induced toxicity.