OBJECTIVE: To study the growth inhibition and mechanism of phytic acid on HepG2 cells.METHODS:HepG2 cells were cultured in vitro and treated with various concentrations(0,1,2,3 mmol/L)of phytic acid.Immunocytochemical stain was used to detect the expression of PCNA.RT-PCR was used to determine the expression of oncogene Mdm2 mRNA in HepG2 cells.Western Blot was used to detect the expression of nuclear transcription factor NF-κB p65.RESULTS:The OD values of PCNA expression in phytic acid groups(1,2,3 mmol/L) were 0.189±0.004,0.179±0.003,0.175±0.002 and in the control group(0 mmol/L) it was 0.209±0.013.The expression in phytic acid groups was lower than that in the control group,and the difference was statistically significant(F=21.491,P0.05).Mdm2 mRNA expression values in phytic acid groups were 0.871±0.058,0.720±0.035,0.593±0.061 and that in the control group was 0.889±0.092,the expression value in phytic acid groups were lower than that in the control group and the difference was statistically significant(F=13.698,P0.05).NF-кB p65 protein expression values in phytic acid groups were 0.933±0.007,0.920±0.014,0.908±0.012,in control group it was 0.965±0.021,and the expression level in phytic acid groups were lower than that in control group and the difference was statistically significant(F=8.472,P0.05).CONCLUSION: Phytic acid inhibits the growth of HepG2 cells.The mechanism may be related to the decrease expression of PCNA,Mdm2,NF-кB p65 with phytic acid,as well as the inhibition of proliferation and induction of apoptosis on HepG2 cells.