Effects of beta-carotene, flavonoid quercitin and quinacrine on cell proliferation and lipid peroxidation breakdown products in BHK-21 cells.

Exposure of BHK-21 (baby hamster kidney cells) to varying concentration of beta-carotene (0- 156 nM) induced a reduction in a cell proliferation rate, increased lipid peroxidation breakdown products, elevated levels of cellular reduced glutathione (GSH), and increased cellular DNA content. Similarly concentration of hydrogen peroxide (0-1.0 microM) added to growth medium truncated rates of cell proliferation as hydrogen peroxide (H2O2) concentration increased and augmented cellular DNA content dramatically. Electrophoresis analysis of DNA from cells treated with H2O2 on agarose gel indicated no excessive DNA fragmentation. Escalating concentration of flavonoid quercitin (0-10 microM) in culture cell medium enhanced the rate of cell growth and diminished levels of lipid peroxidation breakdown products. Quinacrine an inhibitor of phospholipase A2 activity not only abated the decline in cellular lipid peroxidation breakdown products but also abridged the rate of cell proliferation. A combination of beta-carotene (50 nM) and H2O2 (100 microM) added to growth medium depressed cell growth further and increased cellular lipid peroxidation breakdown products. High levels of lipid peroxidation breakdown products were also evident in newly established cultures but these levels decreased with increased growth rate.