Planta Med 2013; 79 - PI29
DOI: 10.1055/s-0033-1352119

Isolation of pyrrolizidine alkaloids from Cynoglossum columnae Ten. (Boraginaceae)

H Damianakos 1, M Jeziorek 2, A Pietrosiuk 2, K Sykłowska-Baranek 2, I Chinou 1
  • 1University of Athens, Dept. of Pharmacognosy and Chemistry of Natural Products, Faculty of Pharmacy, 15771 Athens, Greece
  • 2Medicinal University of Warsaw, Faculty of Pharmacy, Dept. of Biology and Pharmaceutical Botany, 02 – 097 Warsaw, Poland

Cynoglossum species such as C. officinale, C. amabile and C. creticum, among other Boraginaceae plants, are known to accumulate pyrrolizidine alkaloids (PAs) as a major means of chemical defense [1]. In the present study one novel PA of the C-7-O, 9-O acyclic diester type has been isolated, having the skeletal formula of 7O-tiglic-9O-(2-deoxy-2-methyl-echimidinic) diester of heliotridine N-oxide 1, from the endemic Greek plant C. columnae. The methanolic extract of the aerial parts has been submitted directly to column chromatography (without reduction) and the collected fractions further subjected to prep-TLC. PA structure has been identified by means of one dimensional 1H/13C, 1H-1H and 1H-13C correlation NMR spectroscopy, while ESI-MS verified the calculated molecular weight. The absolute configuration of the necine base as heliotridine was deduced according to observed NOESY correlations, while the stereochemical structure of the 9-O-esterified necic acid was not determined. Moreover, three known pyrrolizidine alkaloids (PAs) were also isolated from C. columnae, namely the N-oxides of echinatine, rinderine and 3'-O-acetylrinderine.

Fig. 1

References:

[1] El-Shazly, A. et al.(1996) Biochem. System. Ecol.24:415 – 421.