In vitro anti-tumoral and immunomodulatory effects of acidic polysaccharides isolated from the fungus Gloeosoma mirabile

Abstract

Polysaccharides from wood-rooting fungi have attracted attention due to their broad pharmacological properties. Herein, we report the antitumor and immunomodulatory activities of acid polysaccharides isolated from fungi Gloeosoma mirabile. The polysaccharide extracts displayed significant antiproliferative activity against cancer cell lines (MCF-7, HCT-116, U-937) in a dose-dependent manner and induction of IL-6 in macrophage RAW 264.7. Furthermore, flow cytometry analysis showed that high polysaccharide concentrations induced apoptosis by 83% in HL-60 cells. Based on gas chromatography-mass spectrometry (GC-MS) and Fourier transform infrared (FT-IR) spectroscopy studies, acidic polysaccharides from G. mirabile were mainly composed of arabinose, α-D-galactopyranose and methyl β-D-galactopyranoside. 2 Experimental Materials and Reagents The reagents were obtained from Merck (Darmstadt, Germany). Culture medium, Dulbecco's Modified Eagle Medium-DMEM (Biowest, REF: L0103-500) and RPMI-1640 (Biowest, REF: L0500-500) were purchased from Biowest. Cell culture medium components such as: fetal bovine serum (FBS) (Biowest, REF: S1810-500), penicillinstreptomycin solution 100X (Biowest, REF: L0022-020) and amphotericin B (Biowest, REF: L0009-020) were also purchased from Biowest. Phosphate buffered saline (PBS) were purchased from Invitrogen Corporation (Burlington, ON, USA). Macrophage cell line RAW 264.7 and tumoral cells was purchased from ATTC. The Interleukin-6 was purchased from Invitrogen. All other solvents and chemicals were of analytical grade. Derivatization reagent (BSTFA) was obtained from Sigma Aldrich Fluka (Fluka, U.S.A.) and MTT [(3-(4,5dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide was obtained from Sigma Aldrich (Sigma, MO, USA). Distilled water was used in all the experiments. Determination of Gloeosoma mirabile The strain of Gloesoma mirabile (Berk. & M.A.Curtis) Rajchenb., Pildain & C.Riquelme (Stereaceae, Russulales, Agaricomycetes) was obtained from basidiomes collected from Brazil,