Detection of natural toxins derived from potatoes by biotin-streptavidin direct ELISA

Abstract

α-solanine (SO) and α-chaconine (CHA) are natural toxins of potato and often cause food poisoning. We have previously developed a polyclonal antibody (anti-Sold antibody) that bind to SO and CHA and used them in an enzyme-linked immunosorbent assay (ELISA). This ELISA has a weak point of low sensitivity in detecting SO and CHA, we have tried to improve it in this study. The SO and CHA in the samples were coated on an ELISA plate, and biotin-labeled anti-Sold antibody and peroxidase-labeled streptavidin were added to the plate. The absorbance of the samples containing SO and CHA prepared in 10 mM phosphate buffer was about 5-fold higher than that of the conventional ELISA. Furthermore, the absorbance of the samples containing SO and CHA prepared in human serum and urine was enhanced about 2.5- and 1.6-fold, respectively, compared to that of the conventional ELISA. Using this ELISA, it was also possible to measure the content of SO and CHA in extracts of potato tubers, peels, and sprouts. On the other hand, this ELISA cross-reacted with solanidine and solasodine, which have similar chemical structures to SO and CHA, and also with cholesterol in serum. Although this ELISA has a detection performance applicable to human biological samples, cross-reactivity should be fully considered when judging the results.