Induction of Apoptosis in Human Hepatoma HepG2 Cell Line by Dandelion Extracts

[[abstract]]Dandelions have long been used as the folk medicine for their choleretic,diuretic and antirheumatic properties and are available today in market for a variety of health benefits. The anti-inflammatory activity of dandelion extracts has been confirmed in animal studies and dandelion flower fractions have been shown to possess both antioxidantive and cytotoxic properties.Considering the long history of the dandelion as the herb medicine, relatively little is known about their efficacy against liver cancer. In the present study,we examined the antioxidantive capabilities and cytotoxicity of aqueous and 70% ethanolic extracts?AED and EED, respectively?of dandelion as well as apoptosis induction and mechanism in human hepatoma HepG2 cell line. Both AED and EED displayed similar patterns on DPPH scavenging activity and reducing power, while only AED exhibited ferrous ion chelating ability. The contents of total phenolic compounds and flavonoids were higher in AED as compared with those of EED. By trypan blue assay, we demonstrated that dandelion extracts reduced viability of HepG2 cells via a dose- and time-dependent manner. Furthermore, apoptotic features such as cell shrinkage, DNA fragmentation, Sub-G1 accumulation, increased fluorescence intensities of annexin V/propidium iodide staining and TUNEL assay were observed in dandelion extracts-treated HepG2 cells. During the process of apoptosis induction, we noticed that administration of dandelion extracts resulted in the activation of caspase-8 protein and alteration of caspase-8 and caspase-3 mRNA expressions. Taking together, our results show that dandelion extracts presented both antioxidantive and cytotoxic effects. The dandelion extracts-induced suppression of cell viability of HepG2 may in part be attributed to their phytochemical contents and as an effective inducer of apoptosis as well