title: Barrenazine A and B; two new cytotoxic alkaloids from an unidentified tunicate.
abstract: [structure: see text] Two novel compounds, barrenazine A (1) and B (2), were isolated from an unidentified tunicate collected at Barren Islands, Madagascar. The two new compounds are of an unprecedented heterocyclic skeleton, namely 1,3,4,6,8,9-hexahydrodipyridino[3,4-b:3',4'-e]pyrazine. The structures of the two alkaloids were elucidated by interpretation of MS, COSY, HMQC, HMBC, NOESY, and (15)N-HMBC data. Barrenazine A exhibits mild cytotoxicity against LOVO-DOX colon carcinoma (with a GI(50) value of 0.9 g/mL)
authors.affiliation: School of Chemistry, Tel-Aviv University, Ramat Aviv 69978, Israel.
authors.forename: Liat
authors.initials: L
authors.lastname: Chill
authors.forename: Maurice
authors.initials: M
authors.lastname: Aknin
authors.forename: Yoel
authors.initials: Y
authors.lastname: Kashman
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D004354:Drug Screening Assays, Antitumor; D014407:Tumor Cells, Cultured; D014561:Urochordata / Q000737:chemistry*
chemical_list: D000970:Antineoplastic Agents