ABSTRACT
The mushroom shiitake (Lentinula edodes (Berkeley) Pegler) is been widely consumed in many countries, including Brazil, because of its pleasant flavor and reports of its therapeutic properties, although there is little available information on the genotoxicity and/or antigenotoxicity of this mushroom. We used the Comet assay and HEp-2 cells to evaluate the in vitro genotoxic and antigenotoxic activity of aqueous extracts of shiitake prepared in three different concentrations (0.5, 1.0 and 1.5 mg/mL) and three different temperatures (4, 22 and 60 ºC), using methyl methanesulfonate (MMS) as a positive control and untreated cells as a negative control. Two concentrations (1.0 and 1.5 mg/mL) of extract prepared at 4 ºC and all of the concentrations prepared at 22 ± 2 and 60 ºC showed moderate genotoxic activity. To test the protective effect of the three concentrations of the extracts against the genotoxicity induced by methyl methanesulfonate, three protocols were used: pre-treatment, simultaneous-treatment and post-treatment. Treatments were repeated for all combinations of preparation temperature and concentration. Two extracts (22 ± 2 ºC 1.0 mg/mL (simultaneous-treatment) and 4 ºC 0.5 mg/mL (post-treatment)) showed antigenotoxic activity.
Subject(s)
Humans , Shiitake Mushrooms , Carcinogenicity Tests , Electrophoresis , Mutagenesis , Shiitake MushroomsABSTRACT
The effects of crude extracts of the mushroom Agaricus blazei Murrill (Agaricaceae) on both DNA damage and placental form glutathione S-transferase (GST-P)-positive liver foci induced by diethylnitrosamine (DEN) were investigated. Six groups of adult male Wistar rats were used. For two weeks, animals of groups 3 to 6 were treated with three aqueous solutions of A. blazei (mean dry weight of solids being 1.2, 5.6, 11.5 and 11.5 mg/ml, respectively). After this period, groups 2 to 5 were given a single ip injection 200 mg/kg DEN and groups 1 and 6 were treated with 0.9 NaCl. All animals were subjected to 70 partial hepatectomy at week five and sacrificed 4, 24 and 48 h or 8 weeks after DEN or 0.9 NaCl treatments (10th week after the beginning of the experiment). The alkaline comet assay and GST-P-positive liver foci development were used to evaluate the influence of the mushroom extracts on liver cell DNA damage and on the initiation of liver carcinogenesis, respectively. Previous treatment with the highest concentration of A. blazei (11.5 mg/ml) significantly reduced DNA damage, indicating a protective effect against DEN-induced liver cytotoxicity/genotoxicity. However, the same dose of mushroom extract significantly increased the number of GST-P-positive liver foci