Chromatographic Separation Of Validamycin A And B

Jinggangmycins, which is effective fungicide against the sheath blight of rice plants, is the most widely used homemade farm-antibiotics. Experiments about separation of validamycin A and validamycin B with anion-exchange resin and cation-exchange resin were carried out.Cation-exchange resin 001X4 was used in our experiment. Optimum separation conditions were obtained when separation was carried out in 20 X 400 mm column: flow rate was 0.5mL/min, adder quantity was 0.7g and eluent was 0.1mol/L pyridine-acetic acid at pH value of 6.0.As to anion-exchange resin A600, the influences of elute flow rate, adder quantities, bed height, eluate pH value on separation of validamycin A and validamycin B were investigated. It was found that the influence of bed height on retention volume was the strongest, compared with other factors. The retention volume could decrease with increase of elute flow rate and adder quantity or decrease of bed height. Validamycin A and validamycin B could be separated effectively in the 10X400 mm column under the optimized conditions: elution flow rate of 19.1 cm/h, adder quantity of 0.7 g, bed height of 33.0 cm and used de-ion water as eluent. Except for Validamycin A and B, other minor components, Validamycin D and E were also separated from crude validamycin powder. The separation was also scaled up. Then a kinetic model was established to describe this procedure, two adsorption coefficients, KbdS[R+] and Kbds[ROH], were calculated. The value of these two coefficients was very high, so the main mechanism that contributed to separation was adsorption. At last, hydrolyzation validamycin B by enzymes were also carried out.