Alkaloids hyoscyamine and scopolamine

FIGURE 14.3 The henbane (Hyoscyamus niger Linne), a member of the nightshade family, whose leaves, with or without the tops, constitute the official drug Hyoscyamus and are a source of the valuable medicinal alkaloids hyoscyamine and scopolamine. 

Both untransformed (Hashimofo and Yamada, 1994) and transformed root cultures of Datura, Hyoscyamus, Atropa and Duboisia species (Robins and Walton, 1993) accumulate high levels of fhe fropane alkaloids, hyoscyamine and scopolamine (Fig. 2.3). These medically imporfanf fropane alkaloids present not only an interesting biochemical problem but also a realistic... 

The tropane alkaloids hyoscyamine and scopolamine (Fig. 3a) fnnction as acetylcholine receptor antagonists and are nsed chnically as parasympatholytics. The illegal drug cocaine also... 

Scheme 3. Biosynthesis of the tropane alkaloids hyoscyamine and scopolamine, the ca-lystegines, and nicotine. Molecular clones have been isolated for the enzymes shown. Abbreviations CYP82E4, nicotine A-demethylase H6H, hyoscyamine 6jS-hydroxylase ODC, ornithine decarboxylase PMT, putrescine A-methyltransferase TR-I, tropinone reductase-I TR-II, tropinone reductase-II.

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