Antiproliferative activity and induction of apoptosis in estrogen receptor-positive and negative human breast carcinoma cell lines by Gmelina asiatica roots.

Low risk of breast cancer has been proposed to be associated with high intake of lignans. We have reported the presence of lignans in Gmelina asiatica roots. There are no scientific reports on the antiproliferative activity of G. asiatica roots. The objective of the present study was to evaluate the effect of ethyl acetate extract from G. asiatica roots (EGAR) on estrogen receptor-positive (MCF-7) and negative (MDA-MB-231) human breast cancer cell lines. The effects of 50% inhibitory concentrations (IC(50)) of EGAR on MCF-7 and MDA-MB-231 cells were determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay kit. The mode of cell death caused by EGAR was determined using dual apoptosis assay kit by observing the cells under fluorescent microscope. The quantification of apoptosis and necrosis in cells caused by EGAR was determined using cell death detection kit through ELISA. Down-regulation of the proliferative activity occurred in a clear dose-dependent response with IC(50) values of 32.9 ± 3.8 μg/mL in MCF-7 and 19.9 ± 2.3 μg/mL in MDA-MB-231 cell lines. Treatment of breast cancer cells with EGAR resulted in significant apoptosis. The EGAR contain lignans and flavonoids. The antiproliferative activity of the extract is attributed to the presence of these secondary metabolites. The results suggest the efficacy of G. asiatica roots as antiproliferative agents on human breast cancer cells, supporting the hypothesis that plants containing lignans have beneficial effects on human breast cancer.