Antioxidant acitivity in vitro and in vivo of the capsule polysaccharides from Streptococcus equi subsp. zooepidemicus

Crude capsule polysaccharides (CCP) were prepared from the culture of Streptococcus equi subsp. zooepidemicus C55129 and were partially purified through an anion-exchange column chromatography to afford partially purified capsule polysaccharides (PCP). The main component of CCP and PCP was hyaluronic acid. In vitro antioxidant assay, the capsule polysaccharides showed strong inhibition of lipid peroxidation and hydroxyl radical scavenging activity and moderate 1,1-diphenyl-2-picryldydrazyl radical scavenging activity. In addition, CCP exhibited much stronger reductive power than PCP. For antioxidant testing in vivo, CCP and PCP were orally administrated over a period of 15 days in a d-galactose induced aged mice model. As results, administration of capsule polysaccharides inhibited significantly the formation of malondialdehyde in mice livers and serums and raised the activities of antioxidant enzymes and total antioxidant capacity in a dose-dependent manner. However, the antioxidant activity of CCP was lower than that of PCP. The results suggest that the capsule polysaccharides from Streptococcus equi subsp. zooepidemicus C55129 have direct and potent antioxidant activities.