RESUMEN
Objective: To study the material basis of cytotoxicity in polysaccharide from Solanum nigrum. Methods: Crude products of polysaccharide were isolated from S. nigrum fruit with free protein being removed by Sevage method. The crude products were decolored by 10% H2O2 and precipitated by 95% ethanol treatment. Polysaccharide-protein complex was isolated by DEAE-52 fiber column and the relative molecular weight was detected by SDS-PAGE. MTT assay was used in detecting the cytotoxicity of polysaccharide-protein complex for MCF-7 cells in vitro. Then polysaccharide-protein complex was separated by SephadexG-200 gel column and the cytotoxicity was detected by MTT method. Results: Polysaccharide-protein complex was isolated by DEAE-52 fiber column and the relative molecular wight was detected by SDS-PAGE as 3.0×10 4 and 2.5×104 for the two polysaccharide-protein complexes, It suggested that IC50 was 804.51 μg/mL by MTT. Glycoproteins A andd B were gained by Sephadex G-200 gel column from polysaccharide-protein complex. The IC50 of glycoproteins A and B were 532.96 and 613.91 μg/mL, respectively. Conclusion: Material basis of cytotoxicity in polysaccharide from S. nigrum is two kinds of glycoproteins whose relative molecular weight are 3.0×104 and 2.5×104.