MORPHINE-FREE POPPIES

Abstract

PICTURE A FIELD OF POPPIES and you're quite likely to think of the licit and illicit drugs derived from the unripe seed capsules of the opium poppy ( Papaver somniferum ). most abundant of these is morphine—usually. But a mutant strain of poppies developed in Australia doesn't produce any morphine at all. Australian and German researchers describe a mutant poppy that accumulates the morphine precursors thebaine and oripavine instead of producing morphine or codeine, another drug along the same biosynthetic pathway [ Nature , 431 ,413 (2004)]. strain was discovered among the progeny of commercial poppies treated with a mutagen. treatment appears to have blocked the biosynthetic pathway to morphine by disrupting the enzyme thebaine demethylase. This enzyme normally removes methyl groups from the morphine precursors; the demethylated intermediates then are transformed to morphine via two different routes. The new poppy puts all the biosynthetic effort into producing thebaine and oripavine, says...