Pyrrolizidine biosynthesis

Hartmann T, Ober D (2000) Biosynthesis and Metabolism of Pyrrolizidine Alkaloids in Plants and Specialized Insect Herbivores. 209. 207-243 Haseley SR, Kamerling JP, Vliegenthart JFG (2002) Unravelling Carbohydrate Interactions with Biosensors Using Surface Plasmon Resonance (SPR) Detection. 218 93-114... 

Some male arctiid moths produce their courtship pheromone from dietary pyrrolizidine alkaloids acquired during feeding by the larvae [ 126]. Conversion of monocrotaline to hydroxydanaidal by males is accomplished by aromatiza-tion, ester hydrolysis and oxidation of an alcohol to the aldehyde [7]. In the case of Utetheisa ornatirx the stereo-configuration at C7 of the dietary alkaloid is the same as the pheromone released (R). In contrast, another arctiid, Creatono-tos transiens, can convert a dietary precursor alkaloid with the (S) configuration at C7 (heliotrine) to (l )-hydroxydanaidal. The biosynthesis occurs by first oxidation-reduction at C7 to convert the stereochemistry and then proceeds through aromatization, hydrolysis, and oxidation [7]. 

Hartmann, T. and Toppel. G. 1987. Senecionine A-oxide, the primary product of pyrrolizidine alkaloid biosynthesis in root cultures of Senecio vulgaris. Phytochemistry, 26 1639-1643. 

Boppre, M. and Schneider, D. (1985). Pyrrolizidine alkaloids quantitatively regulate both scent organ morphogenesis and pheromone biosynthesis in male Creatonotos moths (Lepidoptera Arctiidae). Journal of Comparative Physiology A 157 569-577. 

Hartmann, T. and Ober, D. (2000). Biosynthesis and metabolism of pyrrolizidine alkaloids in plants and specialized insect herbivores. Topics in Current Chemistry 209 207-243. 

Wink, M. L Schneider, D. and Witte, L. (1988). Biosynthesis of pyrrolizidine alkaloid-derived pheromones in the arctiid moth, Creatonotos transiens stereochemical conversion of heliotrine. Zeitschrift fiir Naturforschung 43c 737-741. 

Robins DJ (1995) Biosynthesis of pyrrolizidine and quinolizidine alkaloids. The Alkaloids, Chemistry and Pharmacology (ed Cordell GA) Vol 46. Academic, San Diego, pp 1-61. 

Over seven-hundred references are concerned with the isolation and chemistry of alkaloids, and approximately one-third of these are devoted to synthesis and biosynthesis. It is perhaps in these areas that the most notable research is to be found. Although it is probably invidious to attempt the exercise, a personal selection of highlights would include new results on the biosynthesis of quinoliz-idine alkaloids (p. 4), the first synthesis of an eleven-membered macrocyclic pyrrolizidine diester (p. 49), the synthesis of Poranthera alkaloids (p. 68), and, in the indole field, the synthesis of tryptoquivalines G and L (p. 152), of a chiral intermediate in the construction of heteroyohimbine alkaloids (p. 167), and of a catharanthine intermediate, using palladium catalysts (p. 186). 

Biosynthesis and Metabolism of Pyrrolizidine Alkaloids in Plants and Specialized Insect Herbivores... 

Figure 9.2. Metabolism of pyrrolizidine alkaloids (PAs) in Senecio vernalis. The substrates for alkaloid biosynthesis, putrescine and spermidine, are derived from primary metabolism. Homospermidine, synthesized by homospermidine synthase (HSS), is the first pathway specific intermediate. It is exclusively incorporated into the necine base moiety of senecionine A-oxide, the backbone structure of all PAs found in this Senecio species. During allocation from the roots as site of synthesis to the shoots, it is chemically modified to provide the species specific PA-pattem.

BOTTCHER, F., ADOLPH, R.D., HARTMANN, T., Homospermidine synthase, the first pathway-specific enzyme in pyrrolizidine alkaloid biosynthesis. Phytochemistry, 1993,32, 679-689. 

ROBINS, D.J., Stereochemistry of enzymic processes in the biosynthesis of pyrrolizidine alkaloids. Experientia, 1991,47, 1118-1122. 

HARTMANN, T SANDER, H., ADOLPH, R.D., TOPPEL, G., Metabolic links between the biosynthesis of pyrrolizidine alkaloids and polyamines in root cultures of Senecio vulgaris. Planta, 1988,175,82-90. 

---