Antioxidant protection of a polysaccharide produced by Chaetomium globosum CGMCC 6882 on H2O2-challenged HepG2 cells

Effective utilization of waste kitchen oil (WKO) is important to environmental protection and economic development. Presently, an endophytic fungus Chaetomium globosum CGMCC 6882 polysaccharide (CGP-WKO) was successfully produced through submerged fermentation with the sole carbon source of WKO. CGP-WKO had a yield of 1.53 ± 0.27 g/L and contained 95.85 % ± 3.02 % carbohydrate and 2.94 % ± 0.62 % protein. Structural feature analysis indicated that CGP-WKO contained glucose, glucosamine, mannose, rhamnose, galactose, fructose, and glucuronic acid in a molar ratio of 30.38: 1.34: 32.22: 9.68: 1.59: 0.62: 3.73. The weight-averaged molecular weight of CGP-WKO was 26.64 kDa, and its polydispersity was 1.48. Moreover, antioxidant capacity detection in vitro demonstrated that when the concentration of CGP-WKO was 1.0 mg/mL, its scavenging effects against 1,1-diphenyl-2-picrylhydrazyl; 2,2′-azinobis-di-(3-ethyl-benzothiazolin-6-sulfonic acid) diammonium salt; and hydroxyl and superoxide radicals were 45.89 % ± 1.89 %, 55.89 % ± 1.12 %, 29.02 % ± 2.61 %, and 52.76 % ± 2.12 %, respectively; and the IC₅₀ values were 6.4612, 0.8888, 13.8585, and 0.9398 mg/mL, respectively. CGP-WKO increased the content of superoxide dismutase, catalase, and glutathione peroxidase and reduced malondialdehyde content in H₂O₂-challenged HepG2 cells. Overall, the present work indicated that CGP-WKO can be used as an antioxidant agent in the food, cosmetics, and pharmaceutical industries.