Investigations on the anti-leukemia and immunomodulating activities of Agaricus blazei extract

The medicinal mushroom Agaricus blazei (AB) is traditionally used as a remedy against various cancer, infection, and immune related diseases [1–3]. In present study, we investigated both the anti-leukemia and immunomodulatory effects of an ethanol-water extract of Agaricus blazei . In MTT and tritiated thymidine incorporation assays, the AB extract showed statistical significant suppression on the growth of human acute promyelocytic leukemia NB-4 (IC 50 values at 82.2±23.5µg/ml and 109.6±51.7µg/ml respectively) and the chronic myelogenous K-562 cells (IC 50 values at 219.2±87.6µg/ml and 138.3±16.5µg/ml respectively) but has no growth-inhibitory effect on human normal liver cells WRL 68. In an attempt to clarify the underlying mechanisms, NB-4 cells were treated with AB extract and resulted in apoptosis characteristic DNA laddering using gel electrophoresis (20, 100 and 400µg/ml, 72h) and enrichment of nucleosome to maximum of 2.5-folds (250µg/ml, 48h) using cell death detection ELISA. To investigate the immunomodulatory effect of AB extract, BALB/c mice were orally fed with water (as control) or extract (100 or 500mg/kg/day, n=7) for 28 days. Splenic lymphocytes isolated from these mice on day-14 and day-28 were incubated with mitogens LPS or Con A for 72h. Our results indicated that both AB extract treated groups significantly lowered the ex-vivo mitogen-stimulated lymphocyte proliferation in tritiated thymidine incorporation assay, with p