Evaluation of the inhibitory abilities of taraxacum formosanum extract and taraxacum of female extract on human breast cancer cells and human colorectal cancer cells

Dandelion is widely consumed as food and traditional herbal medicine around the world. The purpose of this research is to study the functional properties of T. formosanum and compare with T. officinale, including inhibitory effects on cancer cell proliferation and migration ability. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay was employed for molecular authentication of T. formosanum and T. officinale. For preparation of T. formosanum water extract (TFE) and T. officinale water extract (TOE), the dried stems and leaves of dandelion were extracted by boiling water. The results of DPPH radical scavenging assay indicated both TOE and TFE exhibited antioxidant activity, and TFE showed significant higher antioxidant activity than TOE (p < 0.05). TOE and TFE demonstrated growth inhibitory effects on four cancer cell lines encompassing breast cancer cell lines (MCF-7, MDA-MB231, SK-BR3) and a colorectal cancer cell line (HCT116) in in vitro cancer cell viability test (MTT assay), and dose-dependent relationship in the concentration range of 0.02~10 mg/mL. TFE showed better growth inhibitory effects than TOE on breast cancer cell lines MCF-7 and MDA-MB231 based on significant lower half maximal inhibitory concentration (IC₅₀) values. In the experiment of normal cell line (NIH3T3), TOE affected the growth of normal cells at high concentrations (10 mg/tnL), whereas TFE did not. There were significant differences between TOE and TFE on normal cells (p < 0.05). The content of triterpenoids in T. formosanum was higher than that of T. officinale (2.41% v.s. 2.17%). In the wound-healing assay, both T. formosanum water extract (TFE) and T. formosanum root water extract (TFRE) inhibited migration ability of breast cancer cell line MDA-MB231, and TFE showed significant higher ability than TFRE (p < 0.01). Our findings showed that similar to TOE, TFE had promising antioxidant and anti-cancer activities. It is for the first time to report comparative results of T. formosanum and T. officinale to evaluate the functional properties of T. formosanum, which could be beneficial to Taiwanese dandelion product development and ex-situ restoration.