Enhanced production of saikosaponins by root culture of Bupleurum falcatum L. using two-step control of sugar concentration.

The effect of sugar concentration on the production of saikosaponins was investigated using a root culture of Bupleurum falcatum L. The formation of the lateral roots, which were induced in the presence of indolebutyric acid, was suppressed as the sugar concentration was increased. After the lateral root tips had emerged from the inoculated roots, however, high concentrations of sugar showed no inhibitory effect on the development of the lateral roots. A two-step culture, with 1% sucrose at the beginning of the culture and addition of 6% sucrose at 14 days, when lateral roots have emerged, greatly improved the productivity, affording 0.8 g/l of saikosaponin-a and -d.