Terminalia ivorensis demonstrates antioxidant properties and alters proliferation, genomic instability and migration of human colon cancer cells in vitro.

Abstract

Colorectal cancer is a global killer that causes approximately 940 thousand deaths annually. Terminalia ivorensis (TI) is a tropical tree, the bark of which is used in African traditional medicine for the treatment of diabetes, malaria and ulcer. This study investigated TI as a potential anticancer agent in human colon cells in vitro. TI was extracted sequentially with petroleum ether, chloroform, ethyl acetate and ethanol. Antioxidant activity was assessed by DPPH and FRAP, and differential effects on cell viability, growth, DNA damage, DNA repair, and migration were measured in human colon cancer cells (CaCo-2) and/or non-cancerous human colonocytes (NCM460). The TI phytochemicals most strongly associated with these effects were identified by partial least-squares discriminant analysis. DPPH and FRAP activity were highest in TI ethyl acetate and ethanol extracts (p=0.001). All TI extracts significantly inhibited cell viability and growth and induced DNA damage and inhibited DNA repair in both cell models. The majority of TI extracts were significantly (p=0.01) more toxic to cancer cells than non-cancerous colonocytes. DNA repair was significantly (p=0.001) inhibited in CaCo-2 cells by ethyl acetate extract compared with NCM460 cells. Migration was also significantly inhibited (p<0.001) in CaCo-2 by ethyl acetate (80%) and ethanol extracts (75%). Specific benzoic acids, flavonoids and phenols were identified to be strongly associated with these effects. TI displayed strong antioxidant activity and specific anticancer effects by inducing cell death and DNA damage, and by inhibiting DNA repair, cell proliferation and migration.