HPLC法同时测定腹泻康片中秦皮甲素和秦皮乙素的含量

目的建立同时测定腹泻康片中秦皮甲素和秦皮乙素含量的方法。方法采用高效液相色谱法,色谱柱:Kromasil C18柱(4.6 mm×250 mm,5μm);流动相:乙腈-0.1%磷酸(8∶92);检测波长:334 nm;流速:1 m L·min-1;柱温:30℃。结果秦皮甲素线性范围为47.2⁴72 ng,r=0.999 0,秦皮乙素线性范围为45.6472 ng,r=0.999 0,秦皮乙素线性范围为45.6⁴56 ng,r=0.999 2,秦皮甲素和秦皮乙素平均加样回收率分别为101.09%和100.51%。结论本方法简便、准确、可靠,适用于腹泻康片中秦皮甲素和秦皮乙素的质量控制。     

Influence of Esculetin on Incidence, Proliferation, and Cell Kinetics of Mammary Carcinomas Induced by 7,12-Dimethylbenz[α]anthracene in Rats on High- and Low-fat Diets

The effects of a high-fat diet and esculetin were investigated on 7,12-dimethylbenz[α]anthracene (DMBA)-induced mammary carcinogenesis in female Sprague-Dawley rats. Rats were given a 5-mg dose of DMBA. Seven days later, they were fed either a high-fat (20% soybean oil) or low-fat (0.5% soybean oil) diet. A half of the rats received diets containing 0.03% esculetin. Esculetin significantly inhibited tumor incidence, growth and cell kinetics of the tumor in the rats fed the high-fat and the low-fat diets. Our findings indicate that DMBA-induced mammary tumorigenesis is affected by lipoxygenase products.     

秦皮中香豆素成分的薄层分离和光密度法测定

秦皮的乙醇提取液在硅胶G薄板上,用氯仿—甲醇—水(30:10:3)的下层25ml加甲酸0.5ml为展开剂,成功地分离了七叶亭、七叶灵、梣皮亭、梣皮甙和宿柱白蜡甙五种香豆素甙和甙元。用岛津CS-910型双波长薄层扫描仪测定其含量。对定量前薄板上分开的组分的定性进行了探讨。测定方法快速、灵敏、稳定、简便,为评价秦皮质量提供了有效的定量方法。     

Induction of apoptosis by esculetin in human leukemia U937 cells through activation of JNK and ERK

Esculetin is a phenolic compound that is found in various natural plant products and induces apoptosis in several types of human cancer cells. However, the underlying mechanisms of its action are not completely understood. In the present study, we used human leukemia cells to gain further insight into the mechanism of esculetin-induced anti-proliferative action and apoptosis. It was found that esculetin inhibits cell viability by inducing apoptosis, as evidenced by the formation of apoptotic bodies, DNA fragmentation, and the accumulation of cells in the sub-G1 phase. Esculetin-induced apoptosis was correlated with mitochondrial dysfunction, leading to the release of cytochrome c from the mitochondria to the cytosol, as well as the proteolytic activation of caspases. The z-DEVD-fmk caspase-3 inhibitor and the ectopic expression of anti-apoptotic Bcl-2 significantly inhibited esculetin-induced apoptosis, demonstrating the important role of caspase-3 and mitochondrial proteins in the observed cytotoxic effect. Furthermore, esculetin selectively increased the phosphorylation of extracellular-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), but not that of other kinases such as Akt and p38 activation. In addition, an ERK-specific inhibitor, PD98059, and a JNK-specific inhibitor, SP600125, showed inhibited sub-G1 phase DNA content, DNA fragmentation, caspase activation, and mitochondrial dysfunction induced by esculetin treatment. These results indicated that the JNK and ERK pathways were key regulators of apoptosis in response to esculetin in human leukemia U937 cells.     

Esculetin modulates cytotoxicity induced by oxidants in NB4 human leukemia cells

Esculetin is a polyphenolic compound with cytoprotective properties. We previously demonstrated the induction of apoptosis by esculetin in NB4 human leukemia cells, as a model, by a mechanism not well understood. To analyse the antioxidant activity of esculetin on apoptosis, we have studied the influence of co-treatments of esculetin at a concentration of 100 μM with exogenous ROS donors, namely tert-butyl-hydroperoxide and hydrogen peroxide, on NB4 cells. Esculetin (100 μM) exerts a protective effect on cell viability and death necrosis or late apoptosis caused by the oxidant t-BHP whereas it potentiates decrease of cell viability and cell death caused by H₂O₂. In the first case, the O₂^? scavenging activity of esculetin (100 μM) could be implicated. In the last one, cytotoxicity by apoptosis induction seems to be related to the increase in O₂^?, among other possible mechanisms. These results contribute to the study of the antitumor properties of esculetin by regulation of redox balance in leukemia cells.     

HPLC法同时测定消炎片中绿原酸、秦皮乙素和咖啡酸的含量

目的:建立HPLC法同时测定消炎片中绿原酸、秦皮乙素和咖啡酸的含量.方法:采用Agilent Eclipse XDB-C18 (250mm×4.6 mm,5μm)色谱柱,以甲醇-乙腈-0.04％磷酸溶液为流动相,梯度洗脱;检测波长为328 nm;流速1.0ml·min -1;进样量20μl;柱温35℃.结果:绿原酸、秦皮乙素和咖啡酸的线性范围分别为1.616 ～40.400μg·ml-1(r=0.999 9,n=7)、5.164～129.100μg ·ml-1(r=1.000 0,n=7)和1.344～ 26.880 μg·ml-1(r=1.000 0,n=7);提取回收率分别为99.08％(RSD=0.6％,n=6)、98.81％(RSD =0.4％,n=6)和98.92％(RSD=0.9％,n=6).结论:本法操作简便、快速、结果准确.     

Enterohaemorrhagic Escherichia coli O157 and non-O157 serovars differ in their mechanisms for iron supply

Clinical isolates of enterohaemorrhagic Escherichia coli, both O157 and non-O157 serotypes, were investigated for siderophore production, for growth promotion by haem and esculetin in iron-restricted conditions, for production of enterohaemolysin and esculin hydrolase, and for the presence of the chuA and ehx genes by PCR. As expected, all the strains produced enterobactin, but the prevalence of other factors varied among the serovars tested. None of the O157 and O26 strains produced aerobactin or "colibactin", whereas among other enterohaemorrhagic E. coli non-O157 serovars the frequencies of aerobactin and "colibactin" production were similar to those of commensal E. coli strains. The ability to use ferric esculetin for growth in iron-limited media was markedly more prevalent among non-O157 serovars and less prevalent among O157 strains compared with commensal E. coli strains. Almost all O157, O26 and O103 strains expressed enterohaemolysin, compared with only 50% of other non-O157 strains. Similarly, almost all O157 and O26 strains utilised haem as a host iron source; the frequency of haem use by other non-O157 strains was generally lower and variable among serovars, such that none of the O103:H2 isolates tested used haem as an iron source. The gene chuA, which encodes the haem transport protein ChuA and which is prevalent in O157:H7 strains, was only rarely noted among non-O157 serovars of enterohaemorrhagic E. coli, even among isolates that could use haem as an iron source. Overall our data demonstrate that O157:H7 and non-O157 serovars, in particular O26:H(-)/H11 and O103:H2, use distinctly different strategies for obtaining iron, and suggest two evolutionary distinct lines of enterhaemorrhagic E. coli.     

Isolation of luteolin 7-O-rutinoside and esculetin with potential antioxidant activity from the aerial parts ofArtemisia montana

The antioxidant activity of Artemisia montana was determined by measuring the radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and inhibitory activity against free radical generation of hepatocytes (AC2F). The methanol extract of A. montana showed strong radical scavenging activity at a concentration of 10.1 microg/ml, and thus fractionated by solvent extraction. Esculetin and luteolin 7-O-rutinoside (scolymoside) were isolated as the active principles from the EtOAc and Interphase fractions, respectively. The antioxidant activity of these compounds were comparable to that of L-ascorbic acid.     

Esculetin antagonizes iron-chelating agents and increases the virulence of Listeria monocytogenes

Iron is an essential compound for the growth and virulence of Listeria monocytogenes. In extracellular environments, iron often requires a siderophore to be acquired by microorganisms. Although it does not produce siderophores, L. monocytogenes can use some exogenous bacterial or fungal siderophores as well as a number of animal or plant o-diphenol compounds to overcome growth inhibition by the iron-chelating agents tropolone and 8-hydroxyquinoline. Esculin, a plant glycoside, can be hydrolysed by L. monocytogenes to the o-diphenol aglucon, esculetin. The latter neutralized in vitro growth inhibition induced by the iron-chelating agents. Furthermore, when injected into infected mice, esculetin enhanced mortality in a dose-dependent manner and increased bacterial counts in spleen induced by sublethal doses of L. monocytogenes. Esculetin apparently functioned as a siderophore for L. monocytogenes in murine tissues.     

HPLC测定二丁颗粒中秦皮乙素的含量

目的 建立二丁颗粒中秦皮乙素的含量测定方法。方法 使用Turer Kromasil C18色谱柱，以甲醇-水-冰醋酸(20：80：0．4)为流动相，检测波长353nm。结果 秦皮乙素在0．0386—0．6182μg范围内呈良好的线性关系，平均回收率为98．45％，RSD=1．3％(n=6)。结论 所用方法简便、灵敏、准确，可用于二丁颗粒的质量控制。