title: Part 1: Effect of vitamin C on the biological activity of two euryfurylbenzoquinones on TLT, a murine hepatoma cell line.
abstract: 2-euryfuryl- and 2-euryfuryl-3-nitro-1,4-benzoquinone Q2 and Q3, prepared via oxidative coupling reactions of sesquiterpene euryfuran 1 to 2-nitro-1,4-benzoquinone and 1,4-benzoquinone, were tested for their cytotoxicity towards TLT cells (a murine hepatoma cell line) in the absence and in the presence of vitamin C. Their cytotoxic profile was completely different. In cells incubated with Q2 (from 1 to 50 microg/ml), cell survival was not modified, both GSH and ATP were depleted to about 50% of control values (at 50 microg/ml); and caspase-3 was activated in a dose-dependent manner. These effects were observed whatever cells were incubated or not in the presence of vitamin C. In the case of Q3, the cytotoxicity was rather unrelated to its concentration but the association of vitamin C plus the highest Q3 concentration (50 microg/ml) results in a strong cell death (more than 60%). At such a concentration, a complete lack of caspase-3 activity was observed, probably due to cell lysis. At lower concentrations of Q3 (1 and 10 microg/ml), caspase-3 activity was lower than that observed in the absence of vitamin C or even under control conditions. Both GSH and ATP were kept fairly constant as compared to control values but in the presence of vitamin C and Q3, at 50 microg/ml, a decrease in their amounts was observed.
authors.affiliation: Departamento de Ciencias Químicas y Farmacéuticas, Universidad Arturo Prat, Iquique, Chile, Avenida Arturo Prat 2120, Casilla 121 Iquique, Chile.
authors.forename: Julio
authors.initials: J
authors.lastname: Benites
authors.forename: Leonel
authors.initials: L
authors.lastname: Rojo
authors.forename: Jaime A
authors.initials: JA
authors.lastname: Valderrama
authors.forename: Henryk
authors.initials: H
authors.lastname: Taper
authors.forename: Pedro Buc
authors.initials: PB
authors.lastname: Calderon
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry* / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000494:pharmacology*; D016227:Benzoquinones / Q000737:chemistry* / Q000494:pharmacology*; D006528:Carcinoma, Hepatocellular / Q000473:pathology*; D053148:Caspase 3 / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D003593:Cytoplasm / Q000187:drug effects / Q000201:enzymology; D004789:Enzyme Activation / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D051379:Mice
chemical_list: D000970:Antineoplastic Agents; D016227:Benzoquinones; C004532:quinone; D000255:Adenosine Triphosphate; D007770:L-Lactate Dehydrogenase; D053148:Caspase 3; D005978:Glutathione; D001205:Ascorbic Acid