Characterization of the sugar-binding specificity of the toxic lectins isolated from Abrus pulchellus seeds

The sugar-binding specificity of the toxic lectins from Abrus pulchellus seeds was investigated by combination of affinity chromatography of glycopeptides and oligosaccharides of well-defined structures on a lectin-Sepharose column and measurement of the kinetic interactions in real time towards immobilized glycoproteins. The lectins showed strong affinity for a series of bi- and triantennary N-acetyllactosamine type glycans. The related asialo-oligosaccharides interact more strongly with the lectins. The best recognized structures were asialo-glycopeptides from fetuin. Accordingly, the kinetic interaction with immobilized asialofetuin was by far the most pronounced. Human and bovine lactotransferrins and human serotransferrin interacted to a lesser extent. The interaction with asialofetuin was inhibited by galactose in a dose dependent manner. Lactose, N-acetyllactosamine and lacto-N-biose exhibited similar degree of inhibition while N-acetylgalactosamine was a poor inhibitor. These results suggested that the carbohydrate-binding site of the Abrus pulchellus lectins was specific for galactose and possess a remarkable affinity for the sequences lactose [-D-Gal-(14)-D-Glc], N-acetyllactosamine [-D-Gal-(14)-D-GlcNAc] and lacto-N-biose [-D-Gal-(13)-D-GlcNAc].     

相思子属三种药材中的氨基酸分析比较

利用全自动氨基酸分析仪和高效液相色谱仪分析比较相思子属三种药材中氨基酸成分及含量。结果9个样品都检测出17种氨基酸和2种色氨酸衍生物。结论:不同样品中的氨基酸含量有所差异,但其中门冬氨酸、谷氨酸、亮氨酸和赖氨酸的含量相对较高。     

中国柔突叶蝉属二新种记述(半翅目,叶蝉科)

记述柔突叶蝉属Abrus Dai et Zhang 2新种,即雷公山柔突叶蝉A.leigongshanensis sp.nov.和凹板柔突叶蝉Abrus concavelus sp.nov..新种模式标本保存于贵州大学昆虫研究所.     

土壤干旱胁迫对毛鸡骨草幼苗生长及某些生理特性的影响

以毛鸡骨草幼苗为试验材料,测定毛鸡骨草在不同水分条件下的生长状况和相关的生理生化指标,结果表明:随着干旱胁迫的增加,毛鸡骨草幼苗的株高、茎粗、复叶长等呈递减趋势,根直径、须根数呈递增趋势;根、叶片脯氨酸含量和叶片可溶性糖的含量均呈先降低再上升的趋势,水势随干旱胁迫的加剧呈先上升后降低的趋势,根系活力随干旱胁迫的加剧呈递减趋势。但是,在严重干旱胁迫下,各生长指标的增长均受到明显的抑制。     

连作条件下毛鸡骨草根际土壤微生物群落功能多样性变化特征

毛鸡骨草是治疗肝病的重要中草药之一,而连作障碍致其产量和品质下降。从主产区广西玉林分别采集正茬、重茬和连作三年的毛鸡骨草根际土壤样品,以种植前水稻土壤为对照,采用Biolog GN2 平板碳源分析技术,研究连作条件下根际土壤微生物群落功能多样性变化特征,以揭示其连作障碍的原因。结果表明,连作导致根际土壤微生物功能多样性显著降低,微生物利用各类碳源的能力下降。主成分分析(PCA)表明,不同种植年限的毛鸡骨草根际土壤微生物群落结构之间存在显著差异,且均与种植前对照明显不同,而同一种植年限不同生长期土壤微生物碳代谢群落结构虽有差异,但并不显著。相关分析表明,其产量与微生物功能多样性指数(如Shannon,Simpson,Mclntosh)以及平均吸光值(AWCD)值正相关,而与第一主成分(PC1)呈显著负相关,说明连作条件下其产量的降低在一定程度上与土壤微生物功能多样性的降低和群落结构的改变有关。     

基于绿色低共熔溶剂法高效提取鸡骨草中的黄酮和皂苷

为了研究鸡骨草中总黄酮和总皂苷的最佳提取工艺,通过单因素试验和星点设计-响应面法,对低共熔溶剂的性质(如种类、组分摩尔比、含水量)、提取温度、提取时间、液料比等多个因素进行考察。结果显示,总黄酮的最佳提取条件为:摩尔比1∶2、含水量30%的氯化胆碱/乙二醇作溶剂,提取温度80℃,提取时间40min,液料比15∶1(mL/g);总皂苷的最佳提取条件为∶摩尔比1∶4、含水量25%的氯化胆碱/乳酸作溶剂,提取温度80℃,提取时间64min,液料比56∶1(mL/g)。在最佳条件下,总黄酮和总皂苷的提取率较传统提取溶剂分别提高了33.3%和96.4%。本研究为鸡骨草中黄酮和皂苷的高效、安全提取提供了一条新思路。     

Abruquinone A,B,D,E,F and G from the Root of Abrus precatorius

Eight flavonoids have been isolated from the root of Abrus precatorius L. Among them, six isoflavanquinones, designated (3R)-abruquinone A, B, D and E, (3S)-abruquinone F and G, are characterized by chemical and spectral means including 1H-1H COSY, 1H-13C COSY and CD methods.     

Cytotoxic and pro-apoptotic effects of Abrus precatorius L. on human metastatic breast cancer cell line, MDA-MB-231

Abrus precatorius is highly regarded as a universal panacea in the herbal medicine with diverse pharmacological activity spectra. This experimental study on the mechanism of the anticancer activity of A. precatorius leaf extracts, may offer new evidence for A. precatorius in the treatment of breast cancer in clinical practice. Cell death was determined by using MTT assay. Further analyses were carried out by doing DNA laddering, PARP cleavage, FACS, semi-quantitative RT-PCR and detection of cellular reactive oxygen species (ROS) by DCFDA assay. A. precatorius showed very striking inhibition on MDA-MB-231 cells. MTT assay showed more than 75 % inhibition of the cells and treated cells indicated visible laddering pattern with thick compact band. PARP cleavage produced 89 kDa cleavage product which was associated with apoptosis. Flow cytometer exhibited a sub-G0/G1 peak as an indicative of apoptosis. mRNA expression level of apoptosis-related genes p21 and p53 was markedly increased in cells treated with the extract as compared to control. The up-regulation of p21 and p53 may be the molecular mechanisms by which A. precatorius extract which induces apoptosis. An increase in the concentration of A. precatorius extract does not generate ROS, instead it reduces ROS formation in MDA-MB-231 cells, as evident from the shift in fluorescence below untreated control. This is the first report showing that A. precatorius leaf extract exhibits a growth inhibitory effect by induction of apoptosis in MDA-MB-231 cells. Our results contribute towards validation of the A. precatorius extract as a potentially effective chemopreventive or therapeutic agent against breast cancer.     

巴戟和鸡骨草的根系研究

调查研究了巴戟和鸡骨草两种药用植物根系的生长和分布与植株年龄、地上部生长及光照条件之间的关系。结果表明,随着植株年龄的增大,根系的生长和吸收中心逐渐下移,根生物量和根长垂直分布的变化反映了这种转移,地上部生长与根生物量有着显著相关性。荫蔽度是影响根系分布面积和深度的重要因素之一。文章还对这两种药用植物人工驯化栽培提出了意见。