PRODUCTION AND CHARACTERIZATION OF POLYCLONAL ANTIBODIES AGAINST THE BITTER SESQUITERPENE LACTONES OF CHICORY (CICHORIUM-INTYBUS L)

Polyclonal antisera against lactucin and lactucopicrin, two bitter-tas ting principles of chicory (Cichorium intybus L.), were obtained after immunization of rabbits with KLH-lactucin and KLH-lactucopicrin conju gates, respectively. In competitive ELISA, the sera from KLH-lactucopi crin-immunized rabbits showed a very low cross-reactivity with other s esquiterpene lactones containing a guaiane skeleton, 0.5% with lactuci n, 1% with a mixture of lactucin and 11 beta,13-dihydrolactucin, and 5 % with 8-deoxylactucin and 11 beta,13-dihydro-8-deoxylactucin. The ser a from rabbits immunized with KLH-lactucin showed 50% cross-reaction w ith 8-deoxylactucin and its 11 beta,13-dihydro derivative and only 0.4 % cross-reaction with lactucopicrin. In competitive ELISAs, chicory ex tracts spiked with free sesquiterpene lactones showed an expected incr ease in inhibition level. These ELISAs seem useful in the assessment o f chicory bitterness.