Electrophoretic mobility in agarose gel as an isolating technique and correlation with synergestic cytotoxicity enhancement

In previously published work, we reported that Saponinum album dramatically improves the inhibition of tumor growth by targeted toxins in mice in a synergistic way. Herein, we report a simplified slab gel based electrophoretic isolation technique to determine the highly effective fraction of Saponinum album with a relative electrophoretic mobility (Rf) of 0.44 from the mixture. In total, four different fractions were separated at a preparative scale, and evaluated by ESI-MS, HPLC and thin layer chromatographic analysis. Electrophoretic mobility and electrochemical properties of the different fractions of saponins from Saponinum album were set into relation to their ability to enhance the cytotoxicity of epidermal growth factor (EGF)-based targeted toxins. We here treated HER-14 cells, which are NIH-3T3 Swiss mouse embryo cells transfected with the human EGF receptor. Untransfected NIH-3T3 cells served as control. The major bulk of Saponinum album (72.3%) (Rf 0.62) migrated to the farthest and was found to be significantly ineffective (p<0.05) in enhancing the cytotoxicity of the targeted toxin, while the second fraction (Rf 0.45) showed an enhancement of 9800-fold. The third (EM 0.30µ) had an enhancement factor of 3200, the fourth (Rf 0.08) was again significantly ineffective (p<0.05) in exhibiting any enhancement of cytotoxicity. This is the first report for the use of slab gel electrophoresis as a convenient isolation technique for saponins.

Acknowledgement: Authors would like to acknowledge Alexander von Humboldt foundation for postdoctoral fellowship.

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