Fucogalactans from Agaricus brasiliensis (EPF-Ab) and A. bisporus var. hortensis (EPF-Ah) were prepared via by aqueous extraction and a purification procedure. EPF-Ab had M(w) 19.4 x 10(3) g/mol and EPF-Ah M(w) 31.1 x 10(3) g/mol. EPF-Ab had a (1 -> 6)-linked alpha-D-Galp main-chain partially substituted in O-2 by non-reducing end-units of alpha-L-Fucp. EPF-Ah had a similar main-chain with O-2 substitution, but was partially methylated at HO-3, as well as having 2.5% non-reducing end-units of beta-D-Gal. In mice, EPF-Ab gave 39% antinociceptive inhibition (ID(50) > 100 mg/kg) and no anti-inflammatory activity. EPF-Ah also gave an inhibition of 39% at ID(50) 0.33 mg/kg and also inhibited by 61% (ID(50) 5.0 mg/kg) total cell migration and by 32% peritoneal capillary permeability, which is related to the anti-inflammatory effect. The small differences in chemical structure in these polysaccharides thus modified their biological activities. (C) 2010 Published by Elsevier Ltd.