title: Withanolides from Withania aristata and their cytotoxic activity.
abstract: Seven new withanolides (1-7), along with three known ones (8-10), were isolated from the leaves of Withania aristata. Their structures were elucidated on the basis of spectroscopic analysis, including 2D NMR experiments and spectrometric techniques, and the absolute configuration of 1 and 2 was established by CD analysis. In the search for new cytotoxic compounds from Withania species, the isolated compounds 1-9, along with two derivatives, were assayed for their cytotoxicity against HeLa, MCF-7 and A-549 human tumor cell lines. Derivative (4S,20R,22R)-27-acetoxy-4-p-bromobenzoyloxy-1-oxo-witha-2,5,16,24-tetraenolide (13) showed cytotoxicity against all the cell lines assayed with IC(50) values ranging from 2.8 to 3.6microM, and (4S,20R,22R)-4,27-diacetoxy-4-hydroxy-1-oxo-witha-2,5,16,24-tetraenolide (12) exhibited an IC(50) value of 5.4microM on the MCF-7 cell line.
authors.affiliation: Instituto Universitario de Bio-Orgánica "Antonio González", Departamento de Química Orgánica, Universidad de La Laguna, and Instituto Canario de Investigación del Cáncer, Avda. Astrofísico Francisco Sánchez 2, 38206 La Laguna, Tenerife, Spain.
authors.forename: Gabriel G
authors.initials: GG
authors.lastname: Llanos
authors.forename: Liliana M
authors.initials: LM
authors.lastname: Araujo
authors.forename: Ignacio A
authors.initials: IA
authors.lastname: Jiménez
authors.forename: Laila M
authors.initials: LM
authors.lastname: Moujir
authors.forename: Jesús T
authors.initials: JT
authors.lastname: Vázquez
authors.forename: Isabel L
authors.initials: IL
authors.lastname: Bazzocchi
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D045744:Cell Line, Tumor; D006801:Humans; D020128:Inhibitory Concentration 50; D032341:Withania / Q000737:chemistry*; D054358:Withanolides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*
chemical_list: D000970:Antineoplastic Agents; D054358:Withanolides