Increase of the cellular growth of old human diploid fibroblasts by radical scavenger: methanolic extract of broad beans.

Abstract

The methanolic extract from broad beans (MEBB), which is comprised of phenolic compounds, has free-radical scavenging activity. The effects of MEBB on cytosolic antioxidant enzymes and cell proliferation were examined in cultures of old (78-84% life-span completed) WI-38 human diploid fibroblasts. Because catechin is polyphenol and has radical scavenging activity, it was used as the control in experiments. We observed that MEBB increased cellular growth when added to the cell culture. In MEBB at 40 and 120 micrograms/mL, the cell proliferation increased by 14 and 27%, respectively, as compared to the control. In catechin, cell proliferation increased as well. Regarding cytosolic glutathione peroxidase (GSH-Px) activity, treatment of old cells with MEBB at 40 and 120 micrograms/mL resulted in decreases as compared to the control. In contrast, catechin showed no similarities to the modification of GSH-Px activity. Cytosolic SOD activity was increased by treatment with 40 micrograms/mL MEBB, and the activity showed a gradual decrease with increased MEBB concentrations. A similar trend occurred in the cells treated with catechin (4-20 microM). These results suggest that cytosolic antioxidant enzyme activities in old cells may be modulated by MEBB treatment. We conclude that there may be a relation between the optimum MEBB concentration for the increase of cellular growth and the MEBB concentration required to exhibit a decrease in GSH-Px activity.