Abstract

Purpose: The purpose of this study was to compare the apoptotic effects of the natural milk thistle seeds as a tincture and the commercial silymarin drug (Legalon) on HepG2 cell line.

Methods: The inhibitory concentration (IC50) was determined via the MTT assay for the natural milk thistle seeds tincture and the commercial silymarin drug. The cell cycle distribution assay was determined via flow cytometry. Apoptosis was confirmed by Annexin V -FITC/PI double staining and the percentages of change in the mean levels of P53, Bcl2, Bax, cytochrome c, and caspase 3 were evaluated via ELISA kits assay.

Results: Milk Thistle tincture and silymarin treated HepG2 cells showed cell cycle arrest at G2M. Both substances showed significant apoptotic effects on HepG2 where the percentage of early apoptotic, late apoptotic, and necrotic cells were higher in the HepG2 cells treated with milk thistle tincture than in those treated with silymarin. The mean levels of P53, Bax, cytochrome c, and caspase 3 increased significantly in the milk thistle tincture treated HepG2 cells compared to silymarin treated ones.

Conclusion: The natural milk thistle seed tincture and the commercial silymarin drug (Legalon) induce the hepatocellular apoptosis by activating the mitochondrion-dependent pathway and cell cycle arrest at G2/M. Milk thistle seeds tincture showed a more significant apoptotic effect on HepG2 cells than the silymarin drug (Legalon) as milk thistle seeds contain other constituents in addition to silymarin such as taxifolin, kaempferol, apigenin, quercetin oleic, and palmitic acid.