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 Químicas y Farmacéuticas, 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]

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