Anti-Growth and Anti-Metastatic Potential of Raw and Thermally Treated Eragrostis tef Extract in Human Cancer Cells

Teff (Eragrostis tef), a gluten-free cereal crop cultivated originally in Northeast Africa, is increasingly utilized due to its nutritional and health benefits. The aim of the present study was to investigate the effects of ethanol extract obtained from raw and thermally treated teff, referred to as RTE and TTE, respectively, on uncontrolled growth and activated metastasis using human cancer cell lines. Both RTE and TTE contained flavones, such as orientin (luteolin 8-C-glucoside) and vitexin (apigenin 8-C-glucoside), and phenolic acids, such as protocatechuic acid and p-coumaric acid. TTE showed higher total phenol, protocatechuic acid, and p-coumaric acid contents, but lower orientin content compared to RTE. RTE and TTE significantly suppressed cell growth of H1299 human lung cancer cells, with TTE exhibiting more pronounced effects than RTE, while both extracts had only minimal effects on the growth of non-malignant human umbilical vein endothelial cells. The growth-inhibitory activities of RTE and TTE in H1299 cells were associated with apoptosis induction and cell cycle arrest at the G2/M phase. TTE produced an additional effect on inducing cell cycle arrest at the S phase in H1299 cells, potentially contributing to its stronger growth-inhibitory effects. Moreover, both RTE and TTE effectively inhibited key events in metastasis, such as invasion, migration, and adhesion, in H1299 cells under non-cytotoxic conditions, with TTE showing stronger effects. In HCT116 human colon cancer cells, a similar pattern of inhibition was demonstrated against the metastatic events, accompanied by reduced levels of matrix metalloproteinase-2 and -9. Our results indicate that teff extracts exhibit in vitro anti-growth and anti-metastatic activities, which are enhanced by thermal treatment of teff.