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

• Published in: Planta Medica
• Main Authors: Damianakos, H, Jeziorek, M, Pietrosiuk, A, Sykłowska-Baranek, K, Chinou, I
• Format: Conference Proceeding
• Language: English
• Published: 21.08.2013
• ISSN: 0032-0943; 1439-0221
• DOI: 10.1055/s-0033-1352119

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 7 O -tiglic-9 O -(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 1 H/ 13 C, 1 H- 1 H and 1 H- 13 C 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.