Casuarinin from the bark of Terminalia arjuna induces apoptosis and cell cycle arrest in human breast adenocarcinoma MCF-7 cells

Casuarinin, a hydrolyzable tannin isolated from the bark of Terminalia arjuna L. (Combretaceae), was investigated for its antiproliferative activity in human breast adenocarcinoma MCF-7 cells. The results showed that casuarinin inhibited the proliferation of MCF-7 by blocking cell cycle progression in the G0/G1 phase and inducing apoptosis. An enzyme-linked immunosorbent assay showed that casuarinin increased the expression of p21/WAF1 concomitantly as the MCF-7 cells underwent G0/G1 arrest. An enhancement in Fas/APO-1 and its two forms of ligands, membrane-bound Fas ligand (mFasL) and soluble Fas ligand (sFasL), might be responsible for the apoptotic effect induced by casuarinin. Our study reports here for the first time that the induction of p21/WAF1 and the activity of Fas/Fas ligand apoptotic system may participate in the antiproliferative activity of casuarinin in MCF-7 cells.