title: Cytotoxic effect of the pentacyclic oxindole alkaloid mitraphylline isolated from Uncaria tomentosa bark on human Ewing's sarcoma and breast cancer cell lines.
abstract: Preparations from Uncaria tomentosa, a South American Rubiaceae, have been used in the Peruvian traditional medicine for the treatment of infective, inflammatory and tumoral processes. In this study, the pentacyclic oxindole alkaloid mitraphylline was isolated from the dried inner bark of this plant species, and its structure elucidated by analysis of NMR spectroscopic data. Mitraphylline was differentially identified from its stereoisomeric pair isomitraphylline by (15)N-NMR. Its antiproliferative and cytotoxic effects have been tested on human Ewing's sarcoma MHH-ES-1 and breast cancer MT-3 cell lines, using cyclophosphamide and vincristine as reference controls. A Coulter counter was used to determine viable cell numbers, followed by the application of the tetrazolium compound MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy phenyl)-2-(4-sulfophenyl)-2H-tetrazolium] an inner salt. A colorimetric method was employed to evaluate cell viability in this cytotoxic assay. Micromolar concentrations of mitraphylline (5 microM to 40 microM) inhibited the growth of both cell lines in a dose-dependent manner. The IC (50) +/- SE values were 17.15 +/- 0.82 microM for MHH-ES-1 and 11.80 +/- 1.03 microM for MT-3 for 30 hours, smaller than those obtained for the reference compounds. This action suggests that the pentacyclic oxindole alkaloid mitraphylline might be a new promising agent in the treatment of both human sarcoma and breast cancer.
authors.affiliation: Department of Pharmacology, Faculty of Pharmacy, University of Seville, Seville, Spain.
authors.forename: Dolores
authors.initials: D
authors.lastname: García Giménez
authors.forename: Elena
authors.initials: E
authors.lastname: García Prado
authors.forename: Teresa
authors.initials: T
authors.lastname: Sáenz Rodríguez
authors.forename: Angeles
authors.initials: A
authors.lastname: Fernández Arche
authors.forename: Rocío
authors.initials: R
authors.lastname: De la Puerta
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy*; D020948:Cat's Claw / Q000737:chemistry*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D026121:Indole Alkaloids / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D020128:Inhibitory Concentration 50; D000078183:Oxindoles; D008517:Phytotherapy; D024301:Plant Bark; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D012512:Sarcoma, Ewing / Q000188:drug therapy*
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D026121:Indole Alkaloids; D000078183:Oxindoles; D010936:Plant Extracts; C509328:mitraphylline