Mechanism of apoptosis induced by peptide-rich fraction from the root of Aster tataricus in liver L-02 cells

To evaluate the hepatotoxicity and its mechanism of the peptide-rich fraction(Fr-2)of the root of Aster tataricus in human liver L-02 cells. Cell viability was assessed by MTT assay and the contents of LDH, ROS, GSH, cytochrome C and Caspase-9/3 were assessed by commercially available kits. Cell apoptosis and mitochondrial membrane potential were measured by flow cytometry. The protein expressions of p-JNK, Bax, Bcl-2 were analysed by Western blot assay. The results demonstrated that the Fr-2 fraction induced apoptosis in a concentration- and time-dependent manner and provoked oxidative stress-associated inflammation in L-02 cells. It was characterized by loss of mitochondrial membrane potential and release of cytochrome c from mitochondria. The enhanced Bax/Bcl-2 ratio and the activated Caspase-9/3 indicated that the Fr-2 fraction induces apoptosis via mitochondria-dependent pathway in liver L-02 cells.