Isolation and comparison of α- and β-D-glucans from shiitake mushrooms (Lentinula edodes) with different biological activities

A polysaccharide-enriched extract obtained from Lentinula edodes was submitted to several purification steps to separate three different D-glucans with beta-(1 -> 6), beta-(1 -> 3),(1 -> 6) and alpha-(1 -> 3) linkages, being characterized through GC-MS, FT-IR, NMR, SEC and colorimetric/fluorimetric determinations. Moreover, in vitro hypocholesterolemic, antitumoral, anti-inflammatory and antioxidant activities were also tested. Isolated glucans exerted HMGCR inhibitory activity, but only beta-(1 -> 6) and beta-(1 -> 3),(1 -> 6) fractions showed DPPH scavenging capacity. Glucans were also able to lower IL-1 beta and IL-6 secretion by LPS-activated THP-1/M cells and showed cytotoxic effect on a breast cancer cell line that was not observed on normal breast cells. These in vitro results pointed important directions for further in vivo studies, showing different effects of each chemical structure of the isolated glucans from shiitake mushrooms.