FORSKOLIN PRODUCTION IN UNTRANSFORMED ROOT CULTURE OF COLEUS-FORSKOHLII

Untransformed cultures of Coleus forskohlii Briq. were initiated from in vitro micropropagated shoots derived from shoot tip culture. Effect s of IAA, IBA and two IAA derivatives, 4-Cl-IAA and 5,6-Cl2-IAA were c ompared for growth and forskolin production in cultured roots grown on different basal media under different culture regimes. The roots grew well in the presence of all dosages of 4-Cl-IAA and 5,6-Cl2-IAA with 25% MS plus 1% sucrose and produced more forskolin as compared with IA A or IBA. The optimum concentrations needed for forskolin production w ere 1 mug l-1 for 5,6-Cl2-IAA and 50 mug l-1 for 4-Cl-IAA. The highest amount of forskolin (0.09%) was raised at 50 mug l-1 4-Cl-IAA after 6 0 days of culture. This enhanced level of forskolin was almost equal t o the content in the wild plant. However, under similar conditions and with 500 mug l-1 IAA or IBA, the amount of forskolin produced was muc h smaller. IAA derivative-induced production of forskolin indicates th e possibility for scaling up of the production of this compound in unt ransformed root culture.