Optimized culture conditions for the production of furanocoumarins by micropropagated shoots of Ruta graveolens

Ruta graveolens in vitro cultures are a potential source of secondary metab olites (furanocoumarins) of significant medical interest. Experiments led i n our laboratory showed that micropropagated shoots were richer in furanoco umarins than any other plant material. In order to optimize the molecule pr oduction by such cultivation systems, several factors related to the cultur e medium were studied. Effects of medium composition on biomass growth and furanocoumarin content were analysed and optimal conditions were determined for phosphate (300 mg l(-1) of NaH2PO4), nitrate (2527 mg l(-1) of KNO3), carbon source (10 g l(-1) of sucrose) and phytohormones (2,4- dichloropheno xyacetic acid (2,4-D) 50 muM and benzylaminopurine (BAP) 50 muM). Ruta shoo t growth and furanocoumarin production were compared for optimized and stan dard culture conditions. Specific medium gave better results in terms of gr owth (t(D) equal to 6.9 days against 8.6 for standard conditions) but no si gnificant differences appeared concerning metabolite concentrations. Howeve r, the present study opens the way to scale-up studies with bioreactor cult ivation systems.