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 immunized with a diosgenin conjugate prepared by succinylation of diosgenin, followed by purification with a silica solid-phase extraction cartridge and active ester conjugation to Limulus polyphemus hemocyanin (LPH). Rabbit serum was evaluated using an indirect competitive ELISA with diosgenin-BSA as the coating conjugate. A reduction in absorbance of 50% could be obtained using concentrations of ca. 0.8  M diosgenin, 30M solasodine and 100M tomatine. The antibody exhibited no affinity for solanidine, a non-spiral glycoalkaloid.