Development of an antibody against diosgenin and spiroaminoketal alkaloids

An antibody was developed that exhibited affinity for diosgenin as well as the spiroaminoketal alkaloids solasodine and tomatidine. Rabbits were immun ized with a diosgenin conjugate prepared by succinylation of diosgenin, fol lowed by purification with a silica solid-phase extraction cartridge and ac tive ester conjugation to Limulus polyphemus hemocyanin (LPH). Rabbit serum was evaluated using an indirect competitive ELISA with diosgenin-BSA as th e coating conjugate. A reduction in absorbance of 50% could be obtained usi ng concentrations of ca. 0.8 muM diosgenin, 30 muM solasodine and 100 muM t omatine. The antibody exhibited no affinity for solanidine, a non-spiral gl ycoalkaloid.