Enzyme-linked immunosorbent assay for secalonic acid D

A competitive enzyme-linked immunosorbent assay was developed for the xanthone dimer secalonic acid D. The immunogen and enzyme marker were prepared by direct reaction of secalonic acid D with bovine serum albumin and horseradish peroxidase, respectively. The resultant conjugates were characterized by UV/VIS spectra and thin layer chromatography. The hapten:protein ratios in the conjugates were estimated by difference UV/VIS spectra and by fluorescent techniques. Immunization procedures were conducted utilizing New Zealand rabbits over a period of 12 weeks. The competitive enzyme-linked immunosorbent assay on microtiter plates showed that secalonic acid D was detectable within a range of 250–25 000 ng/assay.