Major terpenoids from flowers and their cytotoxic activity .

In addition to known constituents of , an acetone extract from ray florets of the plant yielded: 5,5'-dibutoxy-2,2'-bifuran (), 5,5'-diisobutoxy-2,2'-bifuran (), α-tocopherol (), β-tocopherol (), loliolide palmitate (), a mixture of calenduladiol esters - 16β-hydroxylupeol-3-O-palmitate () and 16β-hydroxylupeol-3-O-myristate (), 1-epiinuviscolide (), inuviscolide (), 3-epiisotelekin (), 4α-hydroxy-9β,10β-epoxy-1β(H)-11(13)-guaien-8α,12-olide (), 4α-hydroxy-1β(H)-9(10),11(13)-guaiadien-8α,12-olide (), loliolide () and 4β,10β-dihydroxy-1α(H),5α(H)-11(13)-guaien-8α,12-olide (). Calenduladiol esters and asperilin () were the major constituents of the extract. Their cytotoxic effect on human normal prostate epithelial cells (PNT-2), human prostate carcinoma cell lines, human skin fibroblasts (HSF) and human melanoma cell lines was examined . Triterpene esters showed no cytotoxicity against nearly all cell lines tested, except for Du145 prostate carcinoma cells (IC - 62.0 μΜ). Asperilin displayed activity against the cell lines under study, especially against three tested lines of melanomas (A375, IC - 17.6 μΜ, WM793, IC - 28.2 μΜ and Hs 294T, IC - 29.5 μΜ).