Fluorescence spectroscopy and docking study in two flavonoids,isolated tectoridin and its aglycone tectorigenin,interacting with human serum albumin: a comparison study

Two flavonoids, tectoridin (TD) isolated from rhizomes of Iris tectorum and hydrolyzed aglycone tectorigenin (TG) were prepared and characterized to compare their different interaction ability with human serum albumin (HSA). Based on the results, the affinity of TG–HSA was stronger than that of TD–HAS, and TG combined more closely with HSA than did TD. HSA fluorescence was quenched by TD/TG. The interactions between TD/TG and HSA involved static quenching. The thermodynamic parameters indicated that both binding processes were spontaneous; hydrogen binding and van der Waals force were the main forces between TD and HSA, whereas a hydrophobic interaction was the main binding force between TG and HSA. Synchronous and 3D fluorescence spectra showed that the binding of TD/TG to HSA induced conformational changes. Moreover, a docking study confirmed the experimental results. Copyright © 2015 John Wiley & Sons, Ltd.     

Tectorigenin inhibits RANKL‐induced osteoclastogenesis via suppression of NF‐κB signalling and decreases bone loss in ovariectomized C57BL/6

Metabolism of bone is regulated by the balance between osteoblast‐mediated bone formation and osteoclast‐mediated bone resorption. Activation of osteoclasts could lead to osteoporosis. Thus, inhibiting the activity of osteoclasts becomes an available strategy for the treatment of osteoporosis. Tectorigenin is an extract of Belamcanda chinensis In the present study, the anti‐osteoclastogenesis effects of tectorigenin were investigated in vitro and in vivo. The results showed preventive and therapeutic effects of tectorigenin at concentrations of 0, 10, 40, and 80 μmol/L in the maturation and activation of osteoclasts. A signalling study also indicated that tectorigenin treatment reduces activation of NF‐κB signalling in osteoclastogenesis. Animal experiment demonstrated that tectorigenin treatment (1‐10 mg/kg, abdominal injection every 3 days) significantly inhibits bone loss in ovariectomized C57BL/6. Our data suggest that tectorigenin is a potential pharmacological choice for osteoporosis.     

Interaction of the β-Transglycosylase of Trichoderma longibrachiatum with Cellulose

The effects of cellulose on the production and stimulation of β-transglycosylase were studied. The β-transglycosylase of Trichoderma longibrachiatum was produced specifically in the presence of cellulose in Czapeck-Dox medium containing sucrose as a sole carbon source. The enzyme activity was stimulated by the addition of cellulose in the reaction mixture, where the transfer reaction product (a water-insoluble glucan) was apparently synthesized on the surface of the added cellulose fibers.

The hyphal wall fraction of the fungus had the same stimulatory effect on β-transglycosylase as the cellulose fibers. A cellulose-like material in this fraction was found by partial acid hydrolysis and gas chromatography. Cellotriose was the smallest substrate effective for the synthesis of a water-insoluble glucan in the presence of cellulose by the β-transglycosylase, though a significant amount of glucan could not be synthesized without the addition of cellulose.     

葛花鸢尾苷的酸水解及其对乙醇脱氢酶激活作用的研究

本文对葛花提取物鸢尾苷经酸解法得到鸢尾苷元的水解工艺及鸢尾苷和鸢尾苷元对乙醇脱氢酶的激活作用进行了研究.结果表明,葛花鸢尾苷酸水解的最佳条件为:固液比1∶1 (mg/mL),甲醇浓度50％,反应温度80℃,反应时间5h,盐酸浓度4％,此条件下,鸢尾苷水解率可达99％以上.鸢尾苷和鸢尾苷元对乙醇脱氢酶均有一定的激活作用,其激活率分别为127.35％和132.35％.酸水解提高了葛花异黄酮类物质的生物利用率.     

高效液相色谱法测定川射干鸢尾苷元磺酸钠及其制剂泰克吉宁注射液含量和有关物质

建立高效液相色谱法测定鸢尾苷元磺酸钠(4′,5,7-三羟基-6-甲氧基异黄酮-5′-磺酸钠)及其制剂泰克吉宁注射液的含量及有关物质。采用C18色谱柱(150×4.6mm,5μm),流动相为甲醇-5%醋酸水(80:20),流速为1.0mL/min,检测波长为263nm。鸢尾苷元磺酸钠在11～100μg/mL范围内线性关系良好,回归方程Y=43.3609X-1.5973(r=0.99998),平均回收率为99.77%(n=9)。最低检测限为0.052μg/mL,与有关物质分离良好。本法快速、简便、准确,专属性强。