Induction of hairy root cultures of Azadirachta indica A.!Juss and their production of azadirachtin and other important insect bioactive metabolites

Hairy root cultures were established from stem and leaf explants of Azadirachta indica A. Juss (neem) following infection with Agrobacterium rhizogenes. Transformation was confirmed using polymerase chain reaction analysis. The cultures had a relatively fast growth rate (0.134 g dry weight day(-1)) and showed a 100-fold increase in biomass over a 4-week culture period. Both the roots and cultivation medium were antifeedant as determined by a no-choice bioassay using the desert locust, Schistocerca gregaria. Azadirachtin, nimbin, salannin, 3-acetyl-1-tigloylazadirachtinin and 3-tigloylazadirachtol were detected in the hairy roots by supercritical fluid chromatography. The cultivation medium contained 3-acetyl-1-tigloylazadirachtinin, 3-tigloylazadirachtol and desacetylsalannin.