Abstract: In this study,the effects of polysaccharides from Portulaca oleracea L.(POPs) on proliferation of 3T3-L1 preadipocytes and its cytotoxicity were investigated.The obtained results suggested that treatment with POPs (0.01-0.5 mg/mL) for 1,3,and 5 d markedly inhibited the proliferation of 3T3-L1 preadipocytes (P<0.01, P<0.001).Compared with the control group,the number of cells in POPs-treatment groups decreased significantly by MTT assay and LDH assay (P<0.01).Through NRU assay,cells treated with POPs for 3 d exhibited lower cell proliferation level compared to that of control group (P<0.05).However,on the 3 d or 5 d POPs treatment,the cytotoxicity of POPs was observed in the high concentration (0.5 mg/mL) POPs-treated groups.Cells showed obvious shrinkage,cracking,floating,etc. These results revealed that all of three methods can be used to evaluate the anti-proliferation activity of POPs on 3T3-L1 preadipocytes.MTT assay and LDH assay were more sensitive than NRU assay.Polysaccharides from P.oleracea mainly affect membrane integrity and mitochondrial function of 3T3-L1 preadipocytes.

Key words: Portulaca oleracea L.polysaccharides, 3T3-L1 preadipocytes, proliferation, cytotoxicity