Five groups of polysaccharides were prepared from mycelium extract and top and bottom fraction of filtrate precipitates by submerged culture of Grifola frondosa at two different media (glucose and PMP medium) and their individual biological activities were studied. These polysaccharides had diverse molecular mass (470-1650 kDa) and different biological activities at the concentrations of 0.01-0.2% (w/v). Most of polysaccharides had antioxidant and free radical scavenging activities after UV irradiation, where G-2 (bottom fraction of filtrate precipitates from glucose medium, MW 770 kDa) and G-3 polysaccharide (mycelium extract from glucose medium, MW 500 kDa) showed strong activity. The P-1 (from top fraction of filtrate precipitates from PMP medium, MW 1650 kDa) and P-3 polysaccharide (from mycelium extract from PMP medium, MW 470 kDa) increased the proliferation of fibroblasts by approximately 23-25%. Other two groups of polysaccharides produced from glucose medium (G-2 and G-3 polysaccharides) showed also notable proliferation activity for fibroblasts. Treatment of fibroblasts with P-3 polysaccharide significantly increased the biosynthesis of collagen by approximately 80%. G-2 and G-3 polysaccharides showed also marked activity. However, G-1 and P-1 polysaccharides had only negligible activity in collagen biosynthesis. (C) 2003 Elsevier Science Inc. All rights reserved.