[Effect of the combination of alkaloids from Euodiae Fructus and berberine in Zuojin Pill on cytotoxicity in HepG2 cells].

OBJECTIVE: To investigate the hepatotoxicity of alkaloids from Euodiae Fructus combined with berberine (BBR) in Zuojin Pill, and to preliminarily explore the possible detoxification mechanism of the combination components. METHODS: The combination ratio of components was determined by the maximum concentration (Cmax) of the chemical components in Zuojin Pill. HepG2 cell model was used to investigate the combined toxicity of the hepatotoxic components from Euodiae Fructus, such as evodiamine (EVO) or dehydroevodiamine (DHED), with BBR for 48 h. The experimental groups were set as follows: the vehicle control group, the EVO group, the DHED group, the BBR group, and the combination group of EVO or DHED with BBR. The cell counting kit-8 (CCK-8) method was used to determine the cell viability, and the combination index (CI) was used to determine the combined toxicity of the components. The alanine transaminase (ALT), aspartate aminotransferase (AST), lactate dehydroge-nase (LDH), and alkaline phosphatase (ALP) activities as well as total bilirubin (TBIL) content in the cell culture supernatant were detected. The protein expression levels of bile acid transporters, such as bile salt export pump (BSEP) and multidrug resistance-associated protein 2 (MRP2), were detected by Western blot. The intracellular malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in HepG2 cells were detected. RESULTS: Compared with EVO or DHED group, the combination of EVO 1 μmol/L with BBR 10 μmol/L or DHED 50 μmol/L with BBR 35 μmol/L significantly increased cell viability of HepG2 cells (P < 0.01), with CI values of 77.89 or 4.49, respectively, much greater than 1. Significant decreases in the activities of ALT, AST, LDH, ALP, and TBIL content in the cell culture supernatant were found in both combination groups (P < 0.05, P < 0.01). Compared with the EVO group, the combination of EVO with BBR upregulated the protein expression levels of BSEP and MRP2. Compared with the DHED group, the combination of DHED with BBR significantly downregulated the protein expression levels of BSEP and MRP2 (P < 0.01). Compared with EVO or DHED group, the combination of EVO or DHED with BBR significantly reduced the MDA content in HepG2 cells (P < 0.05, P < 0.01). CONCLUSION: A certain ratio of BBR combined with EVO or DHED had an antagonistic effect on HepG2 cytotoxicity, which might be related to regulating the expression of bile acid transpor-ters, and reducing lipid peroxidation damage.