Anti-inflammatory and anti-allergic activities of Skipjack tuna (Katsuwonus pelamis) dark muscle hydrolysates evaluated in cell culture model

Background: Oxidative stress and inflammation are inextricably linked and play major roles in the onset and development of Non-communicable diseases (NCD) which are the most common cause of death and disability in modern world. Hydrolyzed proteins have also been suggested to be used to manage adverse food allergic reaction. Therefore, this study aimed to investigate anti-inflammatory and anti-allergy activities of dark muscle tuna hydrolysates using biological cell line systems as a function of enzyme, the extent of hydrolysis and molecular weight range.Methods: Dark muscle tuna hydrolysates were prepared with two different enzyme types; Alcalase and Flavourzyme. Anti-inflammation activity was measured by inhibitory effect of nitric oxide (NO) production on lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. Anti-allergy was determined from ability of hydrolysates to inhibit b-hexsosaminidase (b-HEX) release from RBL-2H3 mast cells. Cytotoxicity was also investigated in both RAW 264.7 macrophage cells and RBL-2H3 mast cells.Results: No cytotoxic effect on RAW 264.7 macrophage cells and RBL-2H3 mast cells was observed. The NO inhibition and b-HEX release were found significant in dose dependent manner (p<0.05). Alcalase hydrolysates demonstrated greater anti-inflammatory and anti-allergic activities than Flavourzyme hydrolysates (p<0.05). IC50 of both effects were lower than the unhydrolyzed control, > 45.44 mg/ml for NO inhibition and > 65.23 mg/ml for b-HEX release inhibition. These effects increased with the extent of hydrolysis and enzyme concentration. The peptide of lowest molecular weight range (< 3 KDa) was highest in anti-inflammatory and anti-allergic actions. Reducing secretion of TNF-a, IL-6 and IL-1b was found greater in Alcalase hydrolysate than Flavourzyme one.Conclusions: Skipjack tuna dark muscle hydrolysates from Alcalase resulted in peptides with anti-inflammation activity, as determined by NO production in LPS-stimulated RAW 264.7 macrophage cells and anti-allergic properties as measured by a suppression of degranulation of sensitized RBL-2H3 cells. Anti-inflammatory effect may be due to their anti-oxidative capacity and relevant inflammatory factors attenuated with hydrolysate by reducing secretion of pro-inflammatory cytokine (TNF-a, IL-6 and IL-1b). Inhibition of b-HEX release by peptides may be due to membrane-stabilizing action or/and blockade of IgE antibody at fragment region.Keywords: Skipjack tuna, anti-inflammation, enzymatic hydrolysate, dark muscle, anti-allergy