ABSTRACT
pH-sensitive polymeric dyes were fabricated by grafting phenol red (PR) and rosolic acid (RA) onto chitosan (CS) by a facile method. Successful grafting was confirmed by 1H NMR, FT-IR, UV-vis, XRD, and elemental analysis. The polymeric dyes exhibited no cell toxicity. The colorimetric pH-sensing films were fabricated by blending the polymeric dyes with CS to establish their pH-dependent color properties. The film color changed in the pH range 4-10, which may indicate food spoilage or wound status. Covalently grafting of polymeric dyes in the films led to excellent color stability, leaching resistance, and reversibility. Hence, the synthesized polymeric dyes had potential as pH-indicative colorants for food and biomedical fields.
Subject(s)
Chitosan/chemistry , Coloring Agents/chemical synthesis , Polymers/chemistry , Bacterial Infections/diagnosis , Cell Line , Cell Survival/drug effects , Coloring Agents/chemistry , Coloring Agents/pharmacology , Food Storage , Humans , Hydrogen-Ion Concentration , Phenolsulfonphthalein/chemistryABSTRACT
Endothelial cell (EC) dysfunction is the underlying cause for the development of several pathologies, and the interdependency between the pancreatic ß-cells and ECs has been established in the pathophysiology of diabetes. ECs release several factors that govern the expression of genes involved in the proliferation, physiology, and survival of the ß-cells. Of the known factors that collapse this intricately balanced system, endothelial dysfunction is the crucial condition that manifests as the causative factor for micro and macrovascular diseases. Our earlier studies demonstrated that activation of nuclear factor erythroid-related factor (Nrf2) renders protection to the ECs experiencing ER stress. In this study, using a co-culture system, the crosstalk between pancreatic cells under ER stress and ECs and the effect of a novel Nrf2 activator Rosolic Acid (RA), on the crosstalk was investigated. ECs pre-treated with different concentrations RA and co-cultured with thapsigargin-induced ER stressed pancreatic ß-cells showed increased levels of Nrf2 and its downstream targets such as heme oxygenase-1 (HO-1) and NADPH-quinone oxidoreductase-1 (NQO-1), and reduction of ER stress evinced by the decreased levels of glucose-regulated protein (GRP) 78 and C/ERB homologous protein (CHOP). The sensitization of ECs using RA, offered protection to pancreatic cells against ER stress as displayed by increased intracellular insulin and upregulated expression of cell survival and proliferative genes BCl2 and PDX-1. In addition, RA treatment resulted in elevated levels of various angiogenic factors, while inflammatory (TNF-α and IL-1ß) and apoptotic markers (CXCL10 and CCL2) decreased. RA treatment normalized the levels of 115 proteins of the 277, which were differentially regulated as revealed by proteomic studies of ER stressed pancreatic ß-cells in co-culture conditions. These findings clearly indicate the role of small molecule activators of Nrf2 not only in restoring the functioning of pancreatic cells but also in increasing the cell mass. Further, the study impinges on the strategies that can be developed to balance the pancreatic microenvironment, leading to the restoration of ß-cell mass and their normophysiology in diabetic patients.
Subject(s)
Aurintricarboxylic Acid/analogs & derivatives , Endoplasmic Reticulum Stress/drug effects , Endothelial Cells/metabolism , Pancreas/drug effects , Animals , Aurintricarboxylic Acid/pharmacology , Aurintricarboxylic Acid/therapeutic use , Humans , Mice , Pancreas/pathology , Tumor MicroenvironmentABSTRACT
Since quorum sensing (QS) is linked to the establishment of bacterial infection, its inactivation represents one of the newest strategies to fight bacterial pathogens. LsrK is a kinase playing a key role in the processing of autoinducer-2 (AI-2), a quorum-sensing mediator in gut enteric bacteria. Inhibition of LsrK might thus impair the quorum-sensing cascade and consequently reduce bacterial pathogenicity. Aiming for the development of a target-based assay for the discovery of LsrK inhibitors, we evaluated different assay set-ups based on ATP detection and optimized an automation-compatible method for the high-throughput screening of chemical libraries. The assay was then used to perform the screening of a 2000-compound library, which provided 12 active compounds with an IC50 ≤ 10 µM confirming the effectiveness and sensitivity of our assay. Follow-up studies on the positive hits led to the identification of two compounds, harpagoside and rosolic acid, active in a cell-based AI-2 QS interference assay, which are at the moment the most promising candidates for the development of a new class of antivirulence agents based on LsrK inhibition.
Subject(s)
Anti-Bacterial Agents/pharmacology , Enzyme Inhibitors/pharmacology , Phosphotransferases (Alcohol Group Acceptor)/antagonists & inhibitors , Quorum Sensing/drug effects , Anti-Bacterial Agents/chemistry , Bacterial Proteins/antagonists & inhibitors , Biomarkers , Dose-Response Relationship, Drug , Drug Discovery/methods , Enzyme Inhibitors/chemistry , High-Throughput Screening Assays , Humans , Recombinant Proteins , WorkflowABSTRACT
Objective: To establish an HPLC-ELSD method for the content determination of rosolic acid in Radix Rubi.Methods: The ELSD-HPLC content determination of rosolic acid was set up using a Vision HT C 18 HL column(250 mm× 4.6 mm ,5 μm), the mobile phase was methanol-0.1% trifluoroacetic acid with a flow rate of 0.8 ml·min-1 , the column temperature was 35℃, the temperature of drift tube heater was 90 ℃ and the gas was with the flow rate of 2.3 L ·min-1 .Results: The linear range of rosolic acid was 0.155-4.346 μg (r=0.999 9).The average recovery was 100.4% with RSD of 1.88% (n =6).Conclusion: The method is simple and accurate.It can be used for the quality control of Radix Rubi.
ABSTRACT
OBJECTIVE: To establish a method for determination of six triterpene acids in solid dispersion tablets of Eriobotryae Folium total triterpenoid acids by HPLC-ELSD.
