Venom gland alkaloids

Some ants make products reminiscent of the coccinellid alkaloids. Three indolizidines are known from the venom gland of Monomorium pharaonis (Figure 9.10), and a pyrrolizidine from a Solenopsis ant has been known for some time. They would appear to be formed from polyketides or fatty acids as in the case of the coccinellines. More pyr-rolizidines and indolizidines with two alkyl and alkenyl groups have been found in Monomorium and Solenopsis species. Tetraponerine ants smear the venom of their poison glands onto prey. The venom consists of tricyclic alkaloids called tetraponerines (Figure 9.10). They are divided... 

More than a dozen 2,5-dialkylpyrrolidines have been identified in the venoms of Solenopsis and Monomor ium species (J7) AH of these compounds are of the trans configuration. Whereas Solenopsis species may produce only one compound in their poison glands, the venoms of Monomorium species generally consist of mixtures of these alkaloids. 

Several N-methylpyrrolidines have been identified in the venoms of Monomorium (Monomorium) species. M. latinode, an Old World species, is distinctive in producing an alkaloidal-rich venom containing two N-methylpyrrolidines with saturated side chains (IV) (6J. On the other hand, the poison gland secretions of several North American species contain N-methylated compounds in which one (V) or both side chains (VI) are terminally unsaturated (6 ) they are accompanied by the corresponding norpyrrolidines. 

It has long been known that salamanders are venomous animals just a century ago Zalesky [1) isolated a poisonous substance from the skin glands. This substance behaved like an alkaloid and was named saman-darine though it is now known to be a mixture of alkaloids. 

Occurrence Since most A. are nerve poisons they cannot form in larger amounts in the animal world, except in skin glands where they are excreted for specific purposes as neurotoxins (e.g. the amphibian venoms samandarine and other salamander alkaloids, tetrod-otoxin, batrachotoxins, bufotenine and other toad poisons, glomerine, serotonine, histamine, tyra-mine and other biogenic amines). Most A. occur in plants as by-products of amino acid metabolism where they are mostly stored in peripheral parts of the plant (leaves, roots, barks, fruits) and much less frequently in the wood. A. occur only rarely as free bases in plants and are mostly found as salts with oxalic, acetic, lactic, and citric acids, etc. Some higher plant families are... 

Ants in the myrmicine genera Solenopsis and Monomorium are distinctive in producing venoms that are dominated by alkaloids rather than proteins (15). Fire ants (Solenopsis spp.) in the subgenus Solenopsis characteristically synthesize poison gland secretions that are dominated by the cis- and trans-isomers of 6-alkyl- or 6-alkylidene-2- methylpiperidines ( ). On the other hand, species in the subgenus Diplorhoptrum frequently produce... 

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