Antiproliferative Activity of Soybean and Tempeh Extracts on Human Colorectal Cancer Cells

Abstract

Tempeh, an indigenous Indonesian soybean product, is produced through a fermentation process of soybean that enhances the bioavailability of its beneficial nutrients such as proteins and phytoestrogens. Recent studies suggest that the fermentation process of tempeh may enhance the biofunctionality properties of soybeans including anticancer activity. The current study is designed to present a comparative analysis to see if defatted extracts of unfermented soybeans and tempeh (fermented soybeans) possess anti-proliferative activity in human colorectal cancer (CRC) cells. The experimental methods involve the production and extraction of soybeans extract (SE) and tempeh extract (TE) at a concentration of 35 g/100 mL (w/v) with 70% ethanol, followed by rotary evaporation and freeze-drying. MTT assays indicated that both SE and TE exhibited inhibitory activity in viability of human CRC cells, with TE demonstrating a more pronounced dose-dependent inhibition of cell growth compared to SE. Cell cycle analysis led to a significant increase of G1 arrest in both SE and TE-treated cells. The induction of apoptosis was observed from the cells treated with both SE and TE. Western blot analysis revealed an increase of PARP cleavage for both treatments, demonstrating activation of apoptotic pathways in SE and TE-treated cells.