Objective: To investigate the effects of serum containing Scutellaria Barbata extract (ESB) on apoptosis rate and mitochondrial transmembrane potential (MTP) of liver cancer cell line H22 from mice in vitro.
Methods: H22 cells were cultured in vitro and divided into 5 groups: blank control group, low-dose ESB group, medium-dose ESB group, high-dose ESB group and fluorouracil (5-Fu) group. Methyl thiazolyl tetrazolium assay was utilized to determine the proliferation rates of H22 cells. Cellular morphology was observed under a transmission electron microscope (EM). The rhodamine 123 was used as a fluorescence probe to label the H22 cells, and the fluorescence intensities were observed with a laser scanning confocal microscope. The fluorescence intensity of H22 cells indicated the MTP of H22 cells.
Results: The inhibition of serum containing ESB on the proliferation of H22 cells in vitro was observerd in a time-dependent manner. The typical morphological changes of apoptosis were observed after incubation with ESB-containing serum in high dose for 48h. The apoptosis rate of blank control group, 5-Fu group, low-dose ESB group, medium-dose ESB group and high-dose ESB group were (0.51±0.32)%, (11.26±2.97)%, (1.07±0.46)%, (3.15±1.12)%, (7.83±2.25)% respectively. ESB could reduce the MTP of H22 cells from mice as compared with those in the untreated group. The MTPs of the blank control group, ESB in low dose, medium dose, and high dose groups and 5-Fu group were (245.45±67.37), (127.42±41.35), (213.68±65.52), (186.34±56.37) and (142.65±39.44) respectively, which was negatively correlated with apoptosis rate.
Conclusion: ESB-containing serum effectively induces apoptosis, which may be related to the decrease of MTP in H22 cells.

Key words: Scutellaria barbata, liver cancer, apoptosis, mitochondrial transmembrane potential, drug- containing serum, in vitro