Preliminary Study on Antibacterial and Antioxidant Activities of Crude Polysaccharide Extract from Grifola Frondosa

In order to determine the antibacterial and antioxidant activities of crude polysaccharides in Grifola frondosa, by using Grifola frondosa as the raw material, the polysaccharides were prepared from Grifola frondosa by hot water extraction and alcohol precipitation. Meanwhile, the oxford cup method was used to study the antibacterial effect of crude polysaccharides in Grifola frondosa on Escherichia coli and Staphylococcus aureus, and the antioxidant activity of crude polysaccharides in Grifola frondosa was determined by DPPH free radical scavenging capacity, hydroxyl radical scavenging ability and total reducing power. The results showed that crude polysaccharides in Grifola frondosa had antibacterial effects on Escherichia coli and Staphylococcus aureus, and the diameters of inhibition zone were respectively 12 mm and 14 mm. The crude polysaccharides in Grifola frondosa had strong scavenging effect on DPPH free radical, and the scavenging rate increased with the increase of concentration in the range of 0.2-1.6 mg·mL^-1. The scavenging rate reached 78.13% when the concentration was 1.6 mg·mL^-1, while decreased to 72.32% when the concentration was 2.0 mg·mL^-1. The total reducing power (OD) of crude polysaccharides in Grifola frondosa was also weak. The total reducing power (OD) value was 0.2-0.4 at the concentration of 0.2-2.0 mg·mL^-1.