Glycation with uronic acid-type reducing sugar enhances the anti-inflammatory activity of fish myofibrillar protein via the Maillard reaction

The role of carboxyl group in uronic acid in enhancing the anti-inflammatory activity of fish myofibrillar protein (Mf) was investigated, when lyophilized Mf was reacted with various reducing sugars at 60 degrees C and 35% relative humidity through the Maillard reaction. After pepsin and trypsin digestion, the anti-inflammatory activity was evaluated by measuring the secretions of tumor necrosis factor-alpha, interleukin-6, interleukin-10, and nitric oxide in lipopolysaccharide-stimulated RAW 264.7 macrophage. The anti-inflammatory activity of Mf was not affected by glycation with glucose or galactose, whereas strongly enhanced by glycation with uronic acid-type reducing sugars: glucuronic acid, galacturonic acid, and alginate oligosaccharide. These results indicate that the presence of carboxyl group in reducing sugar is important for enhancing the anti-inflammatory activity of Mf. This study also shows that the enhanced effect could depend upon the number of carboxyl group in bound reducing sugar.

Automated summary

This study investigated the role of carboxyl group in uronic acid in enhancing the anti-inflammatory activity of fish myofibrillar protein. Lyophilized Mf was reacted with various reducing sugars through the Maillard reaction, and the anti-inflammatory activity was evaluated. The results showed that glycation with uronic acid-type reducing sugars greatly enhanced the anti-inflammatory activity of Mf, while glycation with glucose or galactose had no significant effect. The study also suggested that the number of carboxyl group in bound reducing sugar could be a determining factor for the enhanced effect.