Inhibitory Effects of Polysaccharides on the activity of CYP1A2 Enzyme in Rat Liver Microsomes in Vitro

OBJECTIVE To establish an LC-MS/MS method for the content determination of acetaminophen in rat liver microsomes and evaluate the inhibitory effects of several polysaccharides includes ginseng polysaccharide, mussel polysaccharide and xanthan gum on the activity of cytochrome P450(CYP)1A2 of rat liver microsomes in vitro. METHODS LC-MS/MS analytical method was eatablished to determine the concentration of acetaminophen in rat liver microsomes while taking gliclazide as the internal standard. α-Naphthalene flavone was used as the positive control drug, a series of polysaccharide solutions, phenacetin(as the specific probe substrate of CYP1A2 enzyme) and rat liver microsomes were incubated in vitro respectively. The content of metabolite acetaminophen was measured by LC-MS/MS and the half inhibitory concentration(IC₅₀) was calculated, so as to evaluate the inhibitory activity of ginseng polysaccharide, mussel polysaccharide and xanthan gum on CYP1A2 enzyme in rat liver microsomes. RESULTS The linear range of acetaminophen was 10-1 000 ng·mL^-1, RSD of precision test was<8.24%, extraction recoveries were 92.53%-103.23%, and RSD of stability test was <10.77%. In mixture metabolic system of rat liver microsome enzymes, the IC₅₀ of ginseng polysaccharide, mussel polysaccharide and xanthan gum were all >100 μmol·L^-1 under this condition. CONCLUSION There is no inhibitory effect of ginseng polysaccharide, mussel polysaccharide and xanthan gum on CYP1A2 enzyme subtypes at normal dose, and they can be used in combination with its substrate.