Detoxifying effects of ultrafiltration fractions of Dendrobium aphyllum peptides on chemical and AAPH-induced oxidative stress

Abstract

Antioxidative peptides were extracted from Dendrobium aphyllum. The Lactobacillus strain was identified as Lactobacillus amylolyticus L6. Analysis of amino acid composition and HPLC-MS/MS analysis indicated a high antioxidative potential of the low molecular weight DA-P fractions which contained 21 different types of polypeptides. DA-P exhibited antioxidative abilities and the DA-P fraction with a size less than 1 kDa displayed optimal activity, as determined through DPPH and ABTS free radical scavenging assays and the reducing power assay. Human erythrocytes subjected to an 2,2′-azobis[2-methylpropionamidine] dihydrochloride (AAPH)-induced hemolysis assay using the DA-P fraction with the size below 1 kDa quenched the intracellular antioxidant system by inhibiting the generation of reactive oxygen species and malondialdehyde and regulating the activity of cellular antioxidative enzymes, including superoxide dismutase, catalase, and glutathione peroxidase. These results provide valuable information for the use of Dendrobium aphyllum as a functional food for Lactobacillus sp.