Characterization, Antioxidant Capacity and Protective Effect of Peptides from Cordyceps militaris Cultivated with Tussah Pupa on Oxidative Injured HepG2 Cells

The antioxidant capacity and protective effect of peptides from protein hydrolysate of Cordyceps militaris cultivated with tussah pupa (ECPs) on H₂O₂-injured HepG2 cells were studied. Results indicated ECP1 (<3 kDa) presented the strongest antioxidant activity compared with other molecular weight peptides. Pretreated with ECPs observably enhanced survival rates and reduced apoptosis rates of HepG2 cells. ECPs treatment decreased the ROS level, MDA content and increased CAT and GSH-Px activities of HepG2 cells. Besides, the morphologies of natural peptides from C. militaris cultivated with tussah pupa (NCP1) and ECP1 were observed by scanning electron microscopy (SEM). Characterization results suggested the structure of NCP1 was changed by enzymatic hydrolysis treatment. Most of hydrophobic and acidic amino acids contents (ACC) in ECP1 were also observably improved by enzymatic hydrolysis. In conclusion, low molecular weight peptides had potential value in the development of cosmetics and health food.