Structure and antioxidant activity of a novel poly-N-acetylhexosamine produced by a medicinal fungus

► Exopolysaccharide (EPS) fractions were collected from liquid medium of a medicinal fungus. ► A novel polyhexNAc about 6 kDa was purified from the low-MW EPS fraction. ► It had a ManNAc-GalNAc-ManNAc main chain with Gal branches. ► It showed significant antioxidant activities in chemical and cell culture assays.