Pyrrolizidine alkaloids from Echium glomeratum (Boraginaceae)
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).
Alali, FQ., Nakanishi, Y., Ibrahim, ES., Qandil, AM., 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