Anti proliferative Effect of Lignosus rhinocerus extract on Colorectal Cancer Cells via Apoptosis and Cell Cycle Arrest

Lignosus rhinocerus, locally known in Malaysia as cendawan susu rimau or tiger milk mushroom, belongs to Polyporaceae family. The mushroom is traditionally used in Malaysia to improve health status as well as cure for cough, asthma, fever, chronic hepatitis and cancer. In this study, pressurized liquid extraction was performed to L. rhinocerus and cellular effects of L. rhinocerus methanol extract(LRME)and aqueous extract (LRAE)were assessed in HCT 116 human colorectal carcinoma cells. LRME exerted higher cytotoxic activity (IC50: 600 μg/ml) compared to LRAE (IC50: 1200 μg/ml) in HCT 116 cells as determined by MTT assay. Interestingly, both extracts did not exert cytotoxic activity on CCD-18co human normal colon fibroblast cells and V79-4 Chinese hamster lung fibroblast cells (IC50> 2000 μg/ml). LRME and LRAE effect on cell cycle and mode of cell death were then investigated in HCT 116 cells as targeted cells. The mode of cell death induced by LRME and LRAE was primarily apoptosis as assessed by Annexin V-FITC/PI dual staining. Under low dose, both extracts arrested HCT 116 cells at G0/G1 phases with corresponding decrease of S-phase population. In conclusion, this is the first report of Lignosus rhinocerus possible mechanism of inducing anti-proliferation on HCT 116 cells.