ABSTRACT
In 1955, the Northern Regional Research Laboratory (NRRL) group reported the successful separation of their gibberellin A into two components – one called gibberellin X, the other gibberellin A, which was thought to be identical with the Japanese gibberellin A. Direct comparison among various GAs isolated by the three groups disclosed that gibberellin A1 and gibberellin A were identical, and gibberellic acid, gibberellin X, and gibberellin A3 were identical; gibberellin A2 was a new GA. This chapter describes both large and small scale isolation and purification procedures. It also presents chromatographic characteristics of GAs and their derivatives. In the large-scale purification of an AE fraction containing free GAs, the fraction is sometimes submitted to countercurrent distribution conducted between ethyl acetate as the upper phase and a phosphate buffer as a lower phase. In the isolation of free GAs, silicic acid adsorption chromatography is often used before or after charcoal chromatography.
