Pyrrolizidine alkaloids from Echium glomeratum (Boraginaceae)
Alali, F. Q., Nakanishi, Y., Ibrahim, E. S., Qandil, A. M., Tawaha, K., Burgess, J., ... Oberlies, N. (2008). Pyrrolizidine alkaloids from Echium glomeratum (Boraginaceae). Phytochemistry, 69(12), 2341-2346. DOI: 10.1016/j.phytochem.2008.06.017
The methanolic extract of the whole plant of Echium glomeratum Poir. (Boraginaceae) has afforded five pyrrolizidine alkaloids, three that were (7S, 8R)-petranine (1), (7S, 8S)-petranine (2), and (7R, 8R)-petranine (3a) or (7R, 8S)-petranine (3b), comprising a tricyclic pyrrolizidine alkaloids subclass; and two that were known but to the species: 7-angeloylretronecine (4) and 9-angeloylretronecine (5). All compounds were tested against a human tumor panel for cytotoxicity; no activity was observed (EC50 values > 20 ?g/ml).