Letinula edodes (Berk.) Pegler (Shiitake) modulates genotoxic and mutagenic effects induced by alkylating agents in vivo

We evaluated the antimutagenic effect of Letinula edodes (Berk.) Pegler (Sh iitake) on the frequency of micronuclei in mice treated with N-ethyl-N-nitr osourea (ENU) or cyclophosphamide (Cl?). Mice were orally (gavage) pretreat ed for 15 consecutive days with solutions of Shiitake (0.6 ml per day, gava ge) prepared at three different temperatures: 4, 21 (RT), and 60 degreesC. Then, the animals were intraperitoneally injected on day 15 with CP (25 or 50 mg/kg) or ENU (50 mg/kg) and killed 24 or 48 h after treatment for evalu ation of micronucleated polychromatic erythrocytes (MNPCEs) in bone marrow and micronucleated reticulocytes (MNRETs). A mixture of L. edodes lineages (LE 95/016, 96/14, 96/17, 96/22, 96/23, 97/27, and 97/28) significantly dec reased the frequencies of MNPCEs and MNRETs induced by CP (25 and 50 mg/kg) . When a single lineage from the mixture (LE 96/17) was tested we also foun d a significant reduction in the frequencies of MNPCEs and MNRETs induced b y both CP or ENU (50 mg/kg). The comet assay was also performed 3 h after E NU treatment using mice pretreated with the single lineage (LE 96/17) of L. edodes. The results showed a high degree of variability with some indicati ons of an antigenotoxic effect. Taken together, our data show that solution s from Shiitake inhibit in vivo mutagenicity of CP and ENU. (C) 2001 Elsevi er Science B.V. All rights reserved.