1: Eur J Med Chem. 2007 Dec 5 [Epub ahead of print] Part 1: Effect of vitamin C on the biological activity of two euryfurylbenzoquinones on TLT, a murine hepatoma cell line. Benites J, Rojo L, Valderrama JA, Taper H, Calderon PB. Departamento de Ciencias QuĂmicas y FarmacĂ©uticas, Universidad Arturo Prat, Iquique, Chile, Avenida Arturo Prat 2120, Casilla 121 Iquique, Chile. 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 50mug/ml), cell survival was not modified, both GSH and ATP were depleted to about 50% of control values (at 50mug/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 (50mug/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 10mug/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 50mug/ml, a decrease in their amounts was observed. PMID: 18179847 [PubMed - as supplied by publisher] Related Links The effect of 3-(5-nitro-2-thienyl)-9-chloro-5-morpholin-4-yl[1,2,4]triazolo[4,3-c]quinazoline on cell growth, cell cycle, induction of DNA fragmentation, and activity of caspase 3 in murine leukemia L1210 cells and fibroblast NIH-3T3 cells. [Cell Biochem Funct. 2006] PMID:16342136 Characterization of cell death events induced by anti-neoplastic drugs cisplatin, paclitaxel and 5-fluorouracil on human hepatoma cell lines: Possible mechanisms of cell resistance. [Biomed Pharmacother. 2007] PMID:17399942 Toxicology and Carcinogenesis Studies of C.I. Pigment Red 3 (CAS No. 2425-85-6) in F344/N Rats and B6C3F1 Mice (Feed Studies). [Natl Toxicol Program Tech Rep Ser. 1992] PMID:12621523 Influence of vitamins C and E on cytotoxic activity of adriamycin in chosen cell cultures. [Acta Pol Pharm. 2002] PMID:12026110 NTP Toxicology and Carcinogenesis Studies of C.I. Direct Blue 218 (CAS No. 28407-37-6) in F344/N Rats and B6C3F1 Mice (Feed Studies). [Natl Toxicol Program Tech Rep Ser. 1994] PMID:12616301