EFFECT OF GIBBERELLIC-ACID ON BERBERINE AND TYROSINE ACCUMULATION IN COPTIS-JAPONICA

The enhancement of berberine production by gibberellic acid (GA(3)) in addition to cell cultures of Coptis japonica was investigated. Coptis cells cultured in the presence of GA(3) gave increases in sucrose uptake, activation of 3-deoxy-D-arabino-heptulosonic acid 7-phosphate (DAHP) synthetase, a putative regulatory enzyme of the shikimate pathway, and free tyrosine levels relative to the controls. The timing of this increase in cellular berberine corresponded closely to the time course of the activation of DAHP synthetase and free tyrosine accumulation. Furthermore, the addition of tyrosine to the medium stimulated berberine production, but only in the presence of GA(3). We propose that GA(3) treatment contributes to berberine production by activating primary metabolic steps involved in tyrosine biosynthesis.