Preliminary Study On Antioxidant Activity Of Oat Peptide And Its Regulatory Pathway

Various kinds of radiation,air pollution,heavy metals and organic agents in the external environment cause the body to generate excessive free radicals to cause oxidative stress,resulting in oxidative damage to biomacromolecule,which ultimately leads to the decline of the body's physiological functions.Therefore,intake of exogenous antioxidants is quite necessary in daily life.Oat is a medicinal and food crop,and it has a high yield and low price in China.Studies have shown that oat products have anti-oxidation and anti-aging effects,but the protective effect of oat peptides on oxidative damage and its mechanism are unclear.In this study,oat peptides were obtained by optimized enzymatic method process.Then,D-galactose(D-Gal)rat model was made and applied to study the antioxidant effect of oat peptides in vivo and to explore the molecular mechanism of anti-oxidation through RNA-Seq technique.The main conclusions are as following:(1)According to the single factor and response surface test,the optimum conditions for the preparation of oat peptides with anti-oxidation function were 1.68 mL/L Alcalase 2.4L FG,10% substrate concentration,94 min hydrolysis time,the pH was adjusted and maintained at 9.84,and the temperature was maintained at 55°C.Under these conditions,the reducing power of oat peptide reached 1.09675,and the yield of oat peptides is 17.02%.(2)Through D-Gal oxidative damage rat model,the antioxidant function of oat peptides was studied in vivo.The results showed that compared with the control group(NG),the model group(MG)produced significant differences in malondialdehyde content(MDA),carbonyl content,glutathione content(GSH),superoxide dismutase(SOD),catalase(CAT)and glutathione peroxidase(GSH-Px)(P<0.05).These results indicated that the oxidative damage rat model was successfully made.The results of oat peptide prevention experiment showed that compared with MG group,MDA and carbonyl content were significantly reduced(P<0.05),GSH content was significantly increased(P<0.05),and the activity of SOD,CAT,GSH-Px was significant increased(P<0.05),which indicated that long-term intake of oat peptides could improve the antioxidant capacity of rats.The oat peptide had application on the protection of the body from oxidative damage.The results of liver and brain hippocampus histopathology and behavioral experiment also showed that oat peptides had the ability to regulate liver lipid metabolism disorders and prevented damage to the brain hippocampus,and could improve rat behavior deficits caused by oxidative damage.(3)The RNA-Seq technique was used to preliminary explore the molecular mechanism of oat peptide antioxidant.The results showed that the up-regulation of the Egfl1,Vwf and Spp1 genes caused a significant increase in the phosphorylation levels of P38,ERK and Akt after D-Gal treatment,which suggested that the MAPK and PI3K/Akt pathways were activated during liver oxidative damage.In addition,the up-regulation of the Egfl1 gene cause the methylation of the downstream gene FoxO,resulting in DNA damage and eventually cell apoptosis.While oat peptides could inhibit the up-regulation of Egfl1,Vwf and Spp1 genes,thereby inhibiting the phosphorylation of P38,ERK and Akt,and the methylation of FoxO,indicating that oat peptides may reduce D-Gal-induced liver damage by participating in MAPK,PI3K/Akt,and FoxO signaling pathways.