Influence of Storage Conditions on Immunomodulating Activities in Lentinus edodes (Berk.)Sing. (Agaricales s.l., Basidiomycetes)

The immunomodulating activities of tumor necrosis factor-α (TNF-α) and nitric oxide (NO) production from mouse macrophages stimulated with extract from Lentinus edodes (Berk.)Sing. stored under different conditions were investigated. TNF-α production was approximately 60 pg ml−1 from macrophages stimulated with the extract from fresh L. edodes in vitro. This effect of the extract from the stored L. edodes showed no drastic difference under low temperature (1 and 5°C) storage. However, TNF-α production from macrophages stimulated with extract from L. edodes stored at 20°C for 7 days decreased to approximately 12 pg ml−1. Also, TNF-α production in vivo from macrophages stimulated with the extract from L. edodes stored at 20°C decreased approximately 20%, compared with that made from the fresh mushroom. This result showed the same tendency as in vitro. NO production from macrophages stimulated with the fresh mushroom extract was 7.4 μM. Although NO production from macrophages stimulated with the extract from the mushroom stored at low temperature was not different significantly from that observed in the fresh L. edodes extract, its production was scarcely detected in the extract from L. edodes stored at 20°C for 7 days. Moreover, lentinan was enzymatically degraded by β-glucanase in L. edodes; in addition the effect of lentinan on the production of these cytokines was decreased with degradation of lentinan. These results showed that the decrease of immunomodulating activities in L. edodes might be reflected by the reduction of lentinan content, which was degraded by β-glucanase during storage of the mushroom.