Quantitative Determination of Vinblastine in Tissue Cultures of Catharanthus roseus by Radioimmunoassay.

A radioimmunoassay has been developed for the quantitative determination of small amounts of vinblastine in tissue cultures of CATHARANTHUS ROSEUS (L.) G. Don. Antibody was obtained by the immunization of rabbits against a conjugate of vinblastine with bovine serum albumin. The antibody had a high affinity (Ka = 1.2 x 10 (9)l/mol) and specificity for vinblastine. The usable range of standard curve for assay was 0.5-10 ng/ml. Crude alkaloid extracts of tissue cultures could be assayed and many samples could be processed in one time. It was found that the vinblastine contents of multiple shoot cultures were lower than that of intact plants but much higher than that of callus cultures.