AROMATASE INHIBITORS FROM URTICA-DIOICA ROOTS

Methanolic extracts of stinging nettle (Urtica dioica L.) roots were i nvestigated for aromatase inhibition. Enzyme inhibition was detected o nly after appropriate chromatographic separation. Inhibitory effects o n aromatase could be demonstrated in vitro for a variety of compounds belonging to different classes. The following compounds developed weak to moderate activity: secoisolariciresinol (1), oleanolic and ursolic acid (2 and 3), (9Z, 11E)-13-hydroxy-9,11-octadecadienoic acid (4), a nd 14-octacosanol (5). Inhibitory effects on aromatase have been known to date neither for pentacyclic triterpenes nor for secondary fatty a lcohols. The potential physiological significance of the above finding s is discussed. Compound 5 is a previously unknown constituent of plan ts.