Inhibition of Proliferation of Breast Cancer Cells MCF7 and MDA-MB-231 by Lipophilic Extracts of Papaya (<i>Carica papaya</i> L. var. Maradol) Fruit

Abstract

Several epidemiological studies have suggested that carotenoids have antineoplasic activities. The objective of this study was to determine the antiproliferative effect of rich carotenoid lipophilic extracts of papaya fruit pulp ( Carica papaya L., cv Maradol) in breast cancer cells, MCF-7 (estrogen receptor positive) and MDA-MB-231 (estrogen receptor negative), and in non-tumoral mammary epithelial cells MCF-12F. Antiproliferative effect was evaluated using the methylthiazolydiphenyl-tetrazolium bromide (MTT) assay and testing lipophilic extracts from different papaya fruit ripening stages (RS1, RS2, RS3, RS4), at different times (24, 48 and 72 h). Papaya lipophilic extracts do not inhibit cell proliferation of MCF-12F and MDA-MB-231 cells. However, MCF-7 cells showed a significant reduction in proliferation at 72 h with the RS4 papaya extract. Results suggested that lipophilic extracts had different action mechanisms on each type of cells and therefore, more studies were required to elucidate such mechanisms.