Nortropane alkaloids structures

Goldmann, A., B. Message, D. Tepfer, R. J. Molyneux, O. Duclos, F. D. Boyer, and A. D. Elbein. Biological activities of the nortropane alkaloid, calystegine B2, and analogs structure-function relationships. J. Nat. Prod. 59 1137-1142. 

Figure 2 Structures of nortropane alkaloids with two or three hydroxyl groups.

Tropane alkaloids (TAs), a class of specialized metabolites with a bicyclic tropane ring in their structures, include clinically important hyoscyamine and scopolamine, the stimulant and narcotic cocaine, and the nortropane alkaloids calystegines. Plants producing TAs are distributed, sometime sporadically, across separate angiosperm families (e.g., Proteaceae, Convolvulaceae, Brassicaceae, Euphorbiaceae, Rhizophoraceae, Solanaceae, and Erythroxylaceae) (Griffin and Lin 2000). Studies of TA biosynthesis have been performed predominantly in Solanaceae plants, and thus little is known regarding TA pathways in other families. 

Glycosidase-inhibiting alkaloids from plants are classified into five structural classes polyhydroxylated pyrrolidines, piperidines, indolizidines, pyrrolizidines, and nortropanes. Furthermore, they also occur as the glycosides. This review describes recent studies on isolation, characterization, glycosidase inhibitory activity, and therapeutic application of the sugar-mimicking alkaloids from plants. 

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