title: Cytotoxic furanogermacranolides from the flowers of Helianthus angustifolius.
abstract: The dichloromethane extract of the flowers of Helianthus angustifolius L. (Asteraceae, Heliantheae) was investigated in vitro for its cytotoxic activity using human cancer cell lines: CCRF-CEM leukemia, MDA-MB-231 breast cancer, U251 glioblastoma, HCT 116 colon cancer cells, and the human lung fibroblast cell line MRC-5. Cytotoxicity-guided fractionation led to the isolation of four related heliangolide-type sesquiterpene lactones. The structures were elucidated by means of NMR spectroscopy and high-resolution mass spectrometry. Of the investigated compounds, 8-methacrylyl-4,15-iso-atriplicolide (1) showed the highest activity against all tested cancer cell lines with IC₅₀ values ranging from 0.26 ± 0.01 µM for CCRF-CEM cells to 4.22 ± 0.26 µM for MRC-5 cells.
authors.affiliation: Department of Pharmacognosy, Institute of Pharmaceutical Sciences, Karl-Franzens-University Graz, Graz, Austria.
authors.forename: Nadine
authors.initials: N
authors.lastname: Kretschmer
authors.forename: Martina
authors.initials: M
authors.lastname: Blunder
authors.forename: Olaf
authors.initials: O
authors.lastname: Kunert
authors.forename: Gerald N
authors.initials: GN
authors.lastname: Rechberger
authors.forename: Rudolf
authors.initials: R
authors.lastname: Bauer
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schuehly
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D045744:Cell Line, Tumor; D035264:Flowers / Q000737:chemistry; D006368:Helianthus / Q000737:chemistry*; D006801:Humans; D020128:Inhibitory Concentration 50; D007783:Lactones / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D010946:Plants, Medicinal / Q000737:chemistry; D012717:Sesquiterpenes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D007783:Lactones; D010936:Plant Extracts; D012717:Sesquiterpenes