Caulerpa taxifolia inhibits cell proliferation and induces oxidative stress in breast cancer cells

Caulerpa taxifolia (M. Vahl) C. Agardh or killer alga is known to possess several bioactive secondary metabolites with unique structural modifications. We investigated anti-oxidant and anti-proliferative activity of C. taxifolia extract (CTE) on breast and lung cancer cells, along with possible effects on mitochondrial membrane potential (MMP) and cell cycle progression. The results revealed up to 6-folds increase in reactive oxygen species (ROS), 2-folds increase in glutathione reductase (GR) activity, 1.7-fold increase in superoxide dismutase (SOD) activity and 1.8-fold change in catalase activity w.r.t. untreated cells i.e. 10.72 to 21.44 nmol/min/mL, 2.0 to 3.49 U/mL and 37.51 to 69.26 U/min/g FW, respectively, in MDA-MB-cells. Likewise, selective anti-proliferative activity with IC50 0.19 + 0.1, 0.27 + 0.1, and 0.43 + 0.1 mu g/mu L, was recorded in MDA-MB-231, T-47D, and H1299 cells. In addition, dose-dependent increase in MMP of up to 40% and G(1/)S phase mitotic arrest was documented by CTE treatment in MDA-MB-231 cells. The results suggest an anti-proliferative and oxidative stress inducing activity of CTE. Changes in MMP and cell cycle arrest further support the anti-cancer effects of CTE. It is believed that C. taxifolia may be considered as a potent source of anti-cancer drugs, subject to further validations.