Multi-Potential Cancer Preventive Efficacy and the Current Safety Status of Agaricus blazei Murill Products

Abstract

Agaricus blazei Murill (ABM), widely known as “Himematsutake” in Japan, has been one of the most popular dietary supplements, especially among the aged-population. ABM has been traditionally used to treat age-related disease such as cardiovascular disease, diabetes, and cancers. Previously, ABM has been shown to have immunostimulatory, antioxidant, antimutagenic, and antitumorigenic properties. In contrast to antitumor effects in rodent tumor cell lines, ABM has only minimal to moderate antitumor effects in a few human cancer cell lines, and antitumor effects were thought to be attributed to a high molecular weight fraction containing highly branched β-glucans, while a low molecular weight fraction of ABM (ABM F500) is a very effective cancer preventive agent. The question of genetic toxicity with agaritine has been scrutinized by using the transgenic F344 rat LacI, a state-of-the-art mutagenicity testing system. Neither K-ABM nor agaritine proved mutagenic. Furthermore, expected DNA adducts (8-HMPdGuo and 8-HMPdAdo) with the postulated mutagenic metabolite 4-(methylhydroxy)phenylhydrazine (HMPD) of agaritine were not found. These new mutagenicity test results provide irrefutable evidence that the earlier positive Ames mutagenicity test results with K-ABM were in fact false positive. Thus, the most recent mutagenicity test results together with the 2-year chronic carcinogenic bioassay strongly suggest neither agaritine nor quality controlled ABM are mutagenic or carcinogenic. Clinical improvement of QOL among cancer patients undergoing chemotherapy complimented by ABM consumption appears to be due to immunostimulation of immunosuppressed patients. Retrospective QOL analysis of 782 cancer patients further supports the thesis that ABM consumption improves QOL in cancer patients. Thus, it is reasonable to expect ABM treatment in combination with cancer chemotherapy may synergistically enhance the outcome of such chemotherapy. Complimentary clinical contribution of ABM to conventional therapy or type II diabetes is also expected. Further clinical studies are necessary to evaluate and validate the chemopreventive potential of ABM F500 as well as clinical merits of ABM as a complimentary medicine in cancer chemotherapy.