ABSTRACT
Pinaceae piperidine alkaloid compounds are water soluble and volatile (Tawara et al. 1993). Still, they can be considered antifeedants rather than volatile deterrents as no evidence has been found that coniferous trees will emit alkaloids. Structurally, Pinaceae alkaloids are 2,6-disubstituted piperidines, nitrogen located in a heterocyclic ring (Stermitz et al. 1990; Tallent and Horning 1956). Based on the biosynthetic route, Pinaceae
6.1 Introduction ............................................................................................119 6.2 Biosynthesis of Pinaceae piperidine alkaloids ................................. 121
6.2.1 Biosynthetic route ..................................................................... 121 6.2.2 Control of biosynthesis ............................................................ 123
6.3 Appearance of Pinaceae piperidine alkaloids .................................. 124 6.3.1 Genera and species-specic differences in the alkaloid
chemistry of conifers ................................................................ 124 6.3.2 Amounts and localization of Pinaceae piperidine alkaloids .... 126
6.4 Biological roles of Pinaceae piperidine alkaloids ............................. 127 6.5 Conclusion ............................................................................................. 128 References ........................................................................................................ 128
alkaloids can also be dened as pseudo-alkaloids, as their carbon backbone is not originated from lysine as in true piperidine alkaloids (Leete and Juneau 1969; Leete et al. 1975). Pinaceae alkaloid compounds have small molecular weights from 137 to 171 g/moL depending on possible double bond, oxygen and hydroxyl group typically located on 6-carbon attached side chain (Gerson and Kelsey 2004; Stermitz et al. 1994; Tawara et al. 1993, 1999) (Figure 6.1). However, double bond, oxygen or hydroxyl group can also be attached to the heterocyclic ring structure (Tawara et al. 1993, 1999).
