title: Free radical scavenging and antioxidant activities of EPS2, an exopolysaccharide produced by a marine filamentous fungus Keissleriella sp. YS 4108.
abstract: The reactive oxygen species (ROS) and free radical-initiated reactions are ascertained to play multiple roles in degenerative or pathological events such as aging, cancer, heart dysfunction and Alzheimer's disease. EPS2 with a mean molecular weight of 1.3 x 10(5) was characterized as an antioxidant exopolysaccharide from the broth of a marine filamentous fungus Keissleriella sp. YS 4108. Compositionally, it is composed of galactose, glucose, rhamnose, mannose and glucuronic acid in an approximate proportion of 50:8:1:1:0.4. The radical eliminating and antioxidant actions of the glycan was assessed in different in vitro systems showing that EPS2 exhibited profound scavenging activities in superoxide radical. As a reinforcement of the action, similar radical scavenging effects of EPS2 were also discerned with both site-specific and non site-specific hydroxyl radical using the deoxyribose assay method. Moreover, EPS2 effectively blocked as well the non site-specific strand-breaking of DNA induced by the Fenton reaction at concentrations of 0.1 and 1 mg/mL. Further investigation of the effect of EPS2 on human low density lipoprotein (LDL) system demonstrated that it significantly inhibited copper-mediated oxidation of LDL in a dose-dependent manner. These results suggest that EPS2, possessing pronounced free radical scavenging and antioxidant activities, could be of considerable preventive and therapeutic significance to some life-threatening health problems such as cancer, atherogenesis and Alzheimer's disease which pathologically initiated by the presence of free radicals leading to the inevitable peroxidation of important biomolecules.
authors.affiliation: Institute of Functional Biomolecules, State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, PR China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Sun
authors.forename: Jian-Wen
authors.initials: JW
authors.lastname: Wang
authors.forename: Lei
authors.initials: L
authors.lastname: Fang
authors.forename: Xiang-Dong
authors.initials: XD
authors.lastname: Gao
authors.forename: Ren-Xiang
authors.initials: RX
authors.lastname: Tan
mesh_terms: D000975:Antioxidants / Q000378:metabolism / Q000494:pharmacology*; D001203:Ascomycota / Q000737:chemistry*; D002614:Chelating Agents / Q000378:metabolism / Q000494:pharmacology*; D008078:Cholesterol, LDL / Q000378:metabolism; D003300:Copper / Q000378:metabolism*; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004249:DNA Damage / Q000187:drug effects; D016166:Free Radical Scavengers / Q000378:metabolism / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism; D017665:Hydroxyl Radical / Q000378:metabolism; D066298:In Vitro Techniques; D015227:Lipid Peroxidation; D010084:Oxidation-Reduction / Q000187:drug effects; D010957:Plasmids / Q000235:genetics; D011134:Polysaccharides / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D012623:Seawater; D013481:Superoxides / Q000378:metabolism
chemical_list: D000975:Antioxidants; D002614:Chelating Agents; D008078:Cholesterol, LDL; D016166:Free Radical Scavengers; D011134:Polysaccharides; D013481:Superoxides; D017665:Hydroxyl Radical; D003300:Copper; D004247:DNA; D005947:Glucose