ABSTRACT
To detect major soy isoflavone glycosides, namely daidzin (DZ) and genistin (GEN), novel open sandwich fluorescence-linked immunosorbent assay (os-FLISA) was developed by taking advantage of enhanced interactions between variable regions of heavy (VH) and light chain (VL) domains in the presence of an antigen. The VH and VL genes were expressed in Escherichia coli as a chimera protein with green fluorescence protein (AcGFP1) and maltose-binding protein (MBP), respectively. Comprehensive characterization of os-FLISA displayed nearly the same specificity as parental DZ- and GEN-specific monoclonal antibody, demonstrating the potential of the developed assay for detection of both DZ and GEN. Their detectable range in this system exhibited at 0.1-12.5 µg mL-1. Subsequent validation analysis revealed that os-FLISA was reliable and accurate system for detection of total soy isoflavone glycosides. Notably, this is the first FLISA based on an open sandwich system, which can be employed for the detection of small molecules.
Subject(s)
Glycine max/chemistry , Immunosorbent Techniques , Isoflavones/analysis , Antibodies, Monoclonal/genetics , Escherichia coli/genetics , Fluorescence , Food Analysis/methods , Green Fluorescent Proteins/genetics , Immunoglobulin Heavy Chains/genetics , Immunoglobulin Light Chains/genetics , Isoflavones/immunology , Limit of Detection , Maltose-Binding Proteins/genetics , Recombinant Proteins/genetics , Reproducibility of ResultsABSTRACT
A new phenanthrene dimer, namely dendropalpebrone (1), was isolated from the whole plant of Dendrobium palpebre, along with nine known compounds (2-10). All of the isolates were evaluated for their hydroxyl radical scavenging effects using a deoxyribose assay. Dendroflorin (10) showed an appreciable activity, and therefore was selected for further studied in RAW264.7 cells. Compound 10 significantly decreased ROS in H2O2-stimulated RAW264.7 cells in a dose-dependent manner, and improved activity of SOD, GPx, and CAT enzymes.
