Cytotoxic effect of Agaricus bisporus and Lactarius rufus β-d-glucans on HepG2 cells

The cytotoxic activity of β-d-glucans isolated from Agaricus bisporus and Lactarius rufus fruiting bodies was evaluated on human hepatocellular carcinoma cells (HepG2). NMR and methylation analysis suggest that these β-d-glucans were composed of a linear (1→6)-linked and a branched (1→3), (1→6)-linked backbone, respectively. They both decreased cell viability at concentrations of up to 100μgmL−1, as shown by MTT assay. The amount of LDH released and the analysis of cell morphology corroborated these values and also showed that the β-d-glucan of L. rufus was more cytotoxic to HepG2 cells than that of A. bisporus. The treatment of HepG2 cells with L. rufus and A. bisporus β-d-glucans at a dose of 200μgmL−1 for 24h promoted an increase of cytochrome c release and a decrease of ATP content, suggesting that these polysaccharides could promote cell death by apoptosis. Both β-d-glucans were tested against murine primary hepatocytes at a dose of 200μgmL−1. The results suggest that the L. rufus β-d-glucan was as cytotoxic for hepatocytes as for HepG2 cells, whereas the A. bisporus β-d-glucan, under the same conditions, was cytotoxic only for HepG2 cells, suggesting cell selectivity. These results open new possibilities for use of mushroom β-d-glucans in cancer therapy.