Synergistic apoptotic effects of ethanolic extracts of ginger and Ganoderma lucidum in a colorectal cancer cell line.

Current conventional therapy for colorectal cancer includes surgery, radiation and chemotherapy, all of which produce side effects. Herbal medicine can control the side effects of conventional treatments. We investigated the synergistic effect of a mixture of Zingiber officinale Roscoe (Ginger) and Ganoderma lucidum extracts on colorectal cancer cell apoptosis in vitro. We prepared ethanolic extracts of ginger (GEE) and G. lucidum (GLEE). Cytotoxicity was evaluated using MTT assay and the half-maximal inhibitory concentration (IC₅₀) of each extract was calculated. The effect of these extracts on apoptosis in cancer cells was assessed using flow cytometry; Bax, Bcl2 and caspase-3 gene expression was evaluated using real-time PCR. GEE and GLEE decreased CT-26 cell viability significantly in a dose-dependent manner; however, the combined application of GEE + GLEE was most effective. Bax:Bcl-2 gene expression ratio, caspase-3 gene expression and the number of apoptotic cells were increased significantly in CT-26 cells treated at the IC₅₀ level of each compound, especially in the GEE + GLEE treatment group. Combined ginger and Ganoderma lucidum extracts exhibited synergistic antiproliferative and apoptotic effects on colorectal cancer cells.