Photoprotective potential of Cordyceps polysaccharides against ultraviolet B radiationainduced DNA damage to human skin cells

Summary Background Ultraviolet (UV) radiation causes DNA damage resulting in photoageing and skin cancer. UVB (290-320nm) interacts directly with DNA, inducing two major photoproducts: cyclobutane-pyrimidine dimers (CPDs) and (6-4) pyrimidine-pyrimidone photoproducts. Cordyceps sinensis (Berk.) Sacc. is a medicinal fungus with reported anticancer and cytoprotective effects. Objectives To investigate genoprotective effects of polysaccharide-rich Cordyceps mycelial components against UVB-induced damage in normal human fibroblast cells. Methods Cultured human fibroblasts (BJ cells) were treated for 30min and, separately, for 24h with hot water extract of Cordyceps fungal mycelia or exopolysaccharides. Cells were washed, irradiated with UVB (302nm), and immediately lysed, after which DNA damage, as strand breaks, was measured using an enzyme-assisted comet assay that detects CPDs. Results DNA damage in UVB-irradiated cells was significantly lowered (P