Quantitative Determination of the Glucosinolates Sinigrin and Progoitrin by Specific Antibody ELISA Assays in Brussels Sprouts.

Glucosinolates from Brussels sprout samples were extracted using an effective concentration of 2% phosphoric acid followed by a neutralization step and heat treatment for removal of inactivated protein. The (potentially) bitter glucosinolates sinigrin and progoitrin were found to be stable during this new extraction protocol. Antisera, as raised against hemisuccinate-linked glucosinolate conjugates, were very specific in sandwich ELISA assays for their corresponding substrates. The ELISA assays showed maximally 7.4% cross-reactivity to other aliphatic glucosinolates and were log-linear from the nM to µM range. In comparison to the standard HPLC method, the sinigrin and progoitrin ELISA respectively slightly and considerably overestimate the actual content of these glucosinolates. The progoitrin content of samples as determined either with the ELISA assay or by HPLC, however, is highly correlated (r(2) = 0.92, n = 12, p < 0.01), suggesting that the former assay is also applicable for the screening of the progoitrin content in Brussels sprout samples.