Biologically active secondary metabolites of barley. IV. Hordenine production by different barley lines

Forty-three lines of barley, including ancestral (wild), landraces, Middle Eastern lines, and modern cultivars, were grown under two different sets of environmental conditions. Hordenine production in barley roots was determined at the one-leaf stage by HPLC analysis and, in two lines only, over a period of 35 days. Forty-two of the 43 lines produced significant amounts of hordenine, although there was no variation among groups. Middle Eastern lines had the highest production with 327 µg/g on a dry weight basis. Production was, however, determined more by environmental conditions during growth than by genetic factors. Hordenine production was up to seven times higher in plants grown under lower light intensities.     

HPLC法测定芦竹碱

采用Hypersill BDS C18色谱柱,以磷酸二氢钠缓冲液/甲醇(70:30,v/v)为流动相,流速0.8 mL/min,275 nm为检测波长,pH=2.4～2.5,建立测定芦竹碱的高效液相色谱法。进样量1～13μg的范围内线性关系良好(r=0.9998)。RSD不大于0.66%。回收率98%～102%,方法操作简单,分析速度快、准确,适用于芦竹碱的产品质量控制分析。     

新型植物源农药芦竹碱的应用与合成研究

介绍了新型植物源农药芦竹碱的应用与合成。以吲哚和二甲胺、甲醛为原料，在乙酸催化下合成了芦竹碱。通过正交实验给出最佳合成条件：反应时间6h，反应温度40℃，二甲胺与吲哚的摩尔比为0.9：1，甲醛与吲哚的摩尔比为1．2：1，乙酸与二甲胺的摩尔比为2．5：1，芦竹碱收率95．6％。     

Biologically active secondary metabolites of barley. II. Phytotoxicity of barley allelochemicals

The release of alkaloids by barley was quantified by HPLC. Hordenine was released from the roots of barley in a hydroponic system for up to 60 days. The amount reached a maximum, 2g/plant/day, at 36 days, then declined. Effects on white mustard by hordenine and gramine included reduction of radicle length and apparent reduction in health and vigor of radicle tips. Transmission electron microscopic examination of white mustard radicle tips exposed to hordenine and gramine showed damage to cell walls, increase in both size and number of vacuoles, autophagy, and disorganization of organelles. The evidence of the morphological and primary effects of barley allelochemicals at the levels released by living plants indicates that the biologically active secondary metabolites of barley may lead to a significant role in selfdefense by the crop.     

Honeydew analysis for detecting phloem transport of plant natural products

Analysis of honeydew excreted by various sap-sucking insects indicated the presence of certain plant secondary constituents in the phloem of their host plants. Honeydew excreted by mealybugs (Pseudococcus longispinus), living onCastanospermum australe, contained the indolizidine alkaloid castanospermine, a potent -glucosidase inhibitor. Similarly, honeydew from green peach aphids (Myzus persicae), feeding onSenecio vulgaris flower buds, contained the pyrrolizidine alkaloid senecionine, itsN-oxide, and hydrolytic products including retronecine. Cardenolides were detected in the honeydew of oleander aphids (Aphis nerii) feeding on oleander (Nerium oleander), indicating that these compounds are translocated in the phloem. On the other hand, honeydew from greenbugs (Schizaphis graminum), feeding on barley, lacked gramine or related indole metabolites. Similarly MBOA, the breakdown product of DIMBOA, was not detected in the honeydew of greenbugs living on DIMBOA-containing wheat.     

Biologically active secondary metabolites of barley. III. A method for identification and quantification of hordenine and gramine in barley by high-performance liquid chromatography

A method was devised for the extraction and quantification of hordenine and gramine from barley (Hordeum vulgare) tissue using HPLC techniques. Quantification was by peak area, the relationship between peak area and concentration of authentic standards being linear for both hordenine and gramine. Significant differences in the ability of three lines of barley to produce hordenine and gramine were detected using this method.     

二羟基芦竹碱新型环保防污涂料的研制

介绍了新型防污剂二羟基芦竹碱的应用与合成。以吲哚和二乙醇胺、甲醛为原料,在乙酸催化下合成了二羟基芦竹碱。通过正交试验给出最佳合成条件:反应时间6 h,反应温度25℃,pH为11。用FT-IR1,HNMR对合成的防污剂进行了表征。并将此防污剂应用到防污涂料中,进行杀菌试验,结果表明,此防污涂料具有明显的杀菌性能。     

D-色氨酸的合成工艺研究

在甲醇钠碱性条件下,以芦竹碱和N-乙酰氨基丙二酸二乙酯为原料进行缩合反应,缩合产物在4%的氢氧化钠水溶液中选择性水解脱羧得到N-乙酰-DL-色氨酸,然后在10%氢氧化钠水溶液中水解得到DL-色氨酸。DL-色氨酸用D-酒石酸拆分,并在苯甲醛催化下实现不对称转化,得到D-色氨酸D-酒石酸盐,最后用三乙胺中和得到目标产物D-色氨酸。确定了缩合和拆分步骤的适宜工艺条件。缩合步骤:甲醇钠摩尔量为芦竹碱的20%,n(芦竹碱)∶(N-乙酰氨基丙二酸二乙酯)=1∶1.2;拆分步骤:乙酸为溶剂,70℃反应,苯甲醛摩尔量为DL-色氨酸的10%,n(DL-色氨酸)∶n(D-酒石酸)=1∶2。     

氨基磺酸催化吲哚Mannich反应绿色合成芦竹碱

[目的]介绍芦竹碱的一种绿色合成方法。[方法]固体酸氨基磺酸作催化剂,吲哚、甲醛、二甲胺3组分在水溶液中发生Mannich反应,30~40℃下合成芦竹碱。[结果]经过实验优化了反应条件,产物经MS和1H NMR得到确认,产率达82%。[结论]该方法绿色环保,成本低,产率高,条件温和,工艺简单,适合工业化生产。