Interference of Asian, American, and Indian (Ashwagandha) Ginsengs in Serum Digoxin Measurements by a Fluorescence Polarization Immunoassay Can Be Minimized by Using a New Enzyme-Linked Chemiluminescent Immunosorbent or Turbidimetric Assay

Abstract

Ginsengs are widely used by the general population. These herbs interfere with serum digoxin measurement using the fluorescence polarization immunoassay. To assess potential interference of different ginsengs (Asian, American, and Indian, also known as Ashwagandha) in vitro and in vivo in a mouse model by using a new enzyme-linked chemiluminescent immunosorbent digoxin assay and an existing turbidimetric assay. Comparisons were made with the fluorescence polarization immunoassay. Aliquots of drug-free serum pools were supplemented with ginseng and apparent digoxin concentrations were measured using enzyme-linked chemiluminescent immunosorbent digoxin assay, turbidimetric assay, and fluorescence polarization immunoassay digoxin assays. Mice were fed with different ginseng preparations and apparent digoxin concentrations were measured 1 and 3 hours later. In a separate experiment, aliquots of serum digoxin pools were further supplemented with ginsengs and the serum digoxin concentrations were measured again. A significant apparent digoxin concentration was observed both in vitro and in vivo using the fluorescence polarization immunoassay, but no apparent digoxin concentration was observed using enzyme-linked chemiluminescent immunosorbent digoxin assay and turbidimetric assay. No interference was observed with enzyme-linked chemiluminescent immunosorbent digoxin assay and turbidimetric assay when digoxin serum pools were further supplemented with various ginsengs. It was concluded that both enzyme-linked chemiluminescent immunosorbent and turbidimetric digoxin assays are free from ginseng interferences.