Structural characterization and protective effect on PC12 cells against H2O2-induced oxidative damage of a polysaccharide from Isaria cicadae Miquel mycelium and its zinc derivative

A homogeneous polysaccharide, ICMP-1, was isolated from the cultured mycelia of Isaria cicadae Miquel by hot water extraction. ICMP-1 (3.87 ×103 kDa) was a heteropolysaccharide mainly consisting of T-α-D-Glcp, →4)-α-D-Glcp-(1→, →4,6)-α-D-Manp-(1→, and →4)-β-D-Galp-(1→. In order to improve the antioxidant activity and the potential applications of ICMP-1, a typical ZnCl2 modification on ICMP-1 was carried out. Fourier-transform infrared spectroscopy (FT-IR), Energy dispersive spectrometer (EDS), scanning electron microscopy (SEM), atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS) analysis confirmed that Zn was successfully introduced into the polymer chain of ICMP-1. The zinc modification derivative (ICMP-1-Zn) can alleviate H2O2-induced oxidative damage on PC12 cells. The stronger antioxidant activity of ICMP-1-Zn may be achieved by promoting the activity of zinc-containing enzymes, such as superoxide dismutase and lactate dehydrogenase.