Tumoricidal Effects of β-Glucans: Mechanisms Include Both Antioxidant Activity Plus Enhanced Systemic and Topical Immunity

Abstract

A study to evaluate the mechanisms of tumoricidal activity resulting from orally administered extract of Agaricus blazei Murill (A. blazei) was performed in mice bearing syngeneic and xenogeneic tumors. Tumor regression was comparably seen in both syngeneic and xenogeneic tumor-bearing mice when administered oral extract preparations. In addition, in a murine syngeneic tumor model, oral administration of water-soluble extracts of A. blazei resulted in significant production of cytokines such as IFN-γ, and TNF-α in peritoneal exudate cells, in parallel with the marked regression of tumor development. The water-soluble extracts also induced pronounced antioxidant activity in in vitro and in vivo assays using two different methods. These results indicate the A. blazei extract may enhance not only the immnunomodulatory effects that promote activity of peritoneal exudate cells for tumor regression but also potentially result in the direct destruction of tumor cells through its antioxidant activity.

ACKNOWLEDGMENTS

This work was supported by the Hi-Tec Research Program of Suzuka University of Medical Science from the Ministry of Education, Culture, Science, and Technology.

Notes

^a Abbreviation is as follows: L/P, lymphocyte/polymorphonuclear leukocyte ratio. L/P activity was evaluated in blood samples obtained on Day 6, 10, and 14 after injections of A. blazei extracts or phosphate-buffered saline control.

^b P < 0.001. Align values in TB on decimals.

^a Abbreviations are as follows: IFN, interferon; TNF, tumor necrosis factor. Peritoneal cavities were lavaged with 5 ml of PBS 4 wk after administration of water control (n = 5) or A. blazei (n = 5) into Ehrlich tumor-bearing mice. After rubbing the abdominal region, peritoneal lavage fluids were examined for cytokine production.

^b p < 0.001.