title: Songaricalarins A-E, cytotoxic oplopane sesquiterpenes from Ligularia songarica.
abstract: Five new highly oxygenated oplopane sesquiterpenes, songaricalarins A-E (1-5), and two known analogues (6 and 7) were isolated from the roots and rhizomes of Ligularia songarica. Their structures and configurations were elucidated by spectroscopic methods, including 2D-NMR techniques, and the structure of 1 was confirmed by single-crystal X-ray diffraction. All compounds were evaluated for in vitro cytotoxic activity against cultured A-549, MCF-7, KB, and KBVIN cells, and 4 exhibited cytotoxicity with EC50 values of 4.9, 0.8, 3.4, and 3.2 μg/mL, respectively.
authors.affiliation: Department of Pharmacognosy, School of Pharmacy, Fudan University, Shanghai 201203, People's Republic of China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.forename: Tzu-Hsuan
authors.initials: TH
authors.lastname: Chen
authors.forename: Kenneth F
authors.initials: KF
authors.lastname: Bastow
authors.forename: Susan L
authors.initials: SL
authors.lastname: Morris-Natschke
authors.forename: Kuo-Hsiung
authors.initials: KH
authors.lastname: Lee
authors.forename: Dao-Feng
authors.initials: DF
authors.lastname: Chen
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D019659:Asteraceae / Q000737:chemistry*; D004354:Drug Screening Assays, Antitumor; D004365:Drugs, Chinese Herbal / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007624:KB Cells; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D018517:Plant Roots / Q000737:chemistry; D027343:Rhizome / Q000737:chemistry; D012717:Sesquiterpenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D004365:Drugs, Chinese Herbal; D012717:Sesquiterpenes