Officinatrione: an unusual (17S)-17,18-seco-lupane skeleton, and four novel lupane-type triterpenoids from the roots of Taraxacum officinale

Novel 5 lupane-type of triterpenois, i.e., 3 beta-acetoxy-18 alpha,19 alpha-epoxylupan-21 beta-ol (1), 18 alpha,19 alpha-epoxy-21 beta-hydroxylupan-3-one (2), lup-18-ene-3,21-dione (3), lupa-18,21-dien-3 beta-yl acetate (4), and (17S)-17,18-seco-lup-19(21)-ene-3,18,22-trione (5), named officinatrione, as well as 16 known compounds from the roots of Taraxacum officinale collected in Takatsuki city, Osaka, Japan. Of the above compounds, 5 was the first lupane-type triterpene, of which the D-ring was open to form a nine-membered ring. Compounds 2 and 5 exhibited moderate cytotoxic activities against L1210 cell line (IC50 10.5 and 10.1 mu M). (c) 2012 Elsevier Ltd. All rights reserved.