Whey peptides exerts antioxidant activity on astrocytes and microglial brain cells

The brain is considered a susceptible organ to oxidative stress (OS) due to its high consumption of oxygen and lipid molecules content, which are prone to lipid peroxidation by the formation of reactive oxygen species (ROS). Whey protein hydrolysate (WPH) have been shown to exert oxidative protection on neuronal cells; however, less attention has been paid to the potential effects on glial cells, the main cells of the brain's immune system. In this work we evaluate the antioxidant potential of whey protein digests on microglia BV2 and astrocytes C6 cells. Whey protein isolates were hydrolyzed by simulated gastric digestion, following the international recognized Infogest protocol. WPH showed high protein concentration (64,6 ± 0,1%) and high degree of hydrolysis (35.2 ± 2,4 %). The WPH ultrafiltrate (5kDa) showed most of the peptides in the molecular range of 200 to 400 Da (40,7 %) evaluated by molecular exclusion in FPLC system. Peptides showed intermediate hydrophobicity analyzed by reversed-phase liquid chromatography. Low fraction of WPH did not compromise cell viability, by MTT assay, and were able to attenuate ROS elevation in microglial and astrocyte cell lineage, measured by DCF assay. LPS was used as an inflammatory stimulus and induced a reduction on GSH content on astrocytes and an increase of NO secretion on microglia cells. Both effects were reversed by the pre-treatment with WPH at 0,5; 1 and 2 mg/mL Peptides resistant to the gastric digestion process have greater potential to be absorbed and exert biological functions. The use of cell cultures to evaluate the bioactivity of food bioactive compound is a useful method for evaluating the mechanisms of action of compounds in the cell. The antioxidant capacity of WPH on glial cells revealed physiological response and big potential for the production of new supplements.