Catalysis mechanism to increase taxol from the extract of Taxus cuspidate callus cultures with alumina chromatography

In our previous research, we had reported a chromatographic protocol using basic Al2O3 column to separate and recover taxol from the extract of Taxus cuspidate callus cultures. On the basis of the amount of taxol detected in the starting materials of the crude plant extract, the recovery of taxol was more than 170% after the basic Al2O3 column chromatography step. It was found that the main source of taxol increase was 7-epi-taxol in the crude extract conversion to taxol by catalysis of the Al2O3 Medium, In this paper, the catalysis mechanism of Al2O3 in converting 7-epi-taxol to taxol was developed by investigating the surface structure of alumina and the formation of activity core of catalysis. It was found that the type of Al2O3, the content of Al2O3 in the stationary phase, and the concentration of H2O in the mobile phase of chromatography could influence the isomeric reaction. The isomerization of 7-epi-taxol to taxol was under the influence of Lewis souci and basic activity cores on the surface of alumina. The strength and type of activity core controlled the procedure of reaction.