Triterpenoids from Parthenium argentatum x P. tomentosa.

Four tetracyclic triterpenoids and lupeol were isolated from the hybrid Parthenium argentatum x P. tomentosa. The new triterpenoids were identified as 16, 24-epoxy-3 alpha-hydroxylanost-8-ene (argentatin E); 16, 24-epoxy-25-hydroxycycloart-1, 11, 22-trien-3-one (argentatin F); 16,24-dihydroxycycloart-20, 25-dien-3-one (argentatin G) and 16, 24-dihydroxycycloart-25-en-3-one (argentatin H). The chemical identities of these compounds were confirmed by the different spectrometric measurements.