Study on cytotoxicity of four 9,10-dihydrophenanthrenes

OBJECTIVE: To investigate the anti-proliferative effect of four 9,10-dihydrophenanthrenes isolated from Pholidota yunnanesis Rolfe on 4 human carcinomatous cells and the mechanism of the induced cytotoxicity. METHODS: Growth inhibition by the four compounds was analyzed using MTT assay. The effect on the cell cycle of HepG2 cells was detected using flow cytometry. The protein expression was determined using Western blot. RESULTS: 9,10- dihydrophenanthrenes showed considerable cytotoxic activity against HepG2 cells; 4,5-dihydroxy-2-methoxy-9,10-dihydrophenanthrene treatment induced the accumulation of cells in the G2/M phase and the protein level of Cdc-2 was not changed but that of Cyclin B1 was decreased in the treated cells. CONCLUSION: 9,10-Dihydrophenanthrenes show cytotoxic activity against HepG2 cells by arresting the cell at G2/M phase.