Antioxidant, anti-inflammatory, and α-amylase inhibitory activities of Ulva lactuca extract

Abstract

In this study, an extract of Ulva lactuca was investigated for its in vitro antioxidant activities (2,2-diphenyl1-picrylhydrazyl radical, hydroxyl radical, and superoxide anion radical scavenging activity, and reducing power) and enzyme inhibitory activities (α-amylase and α-glucosidase). The anti-inflammatory effect of U. lactuca extract was evaluated in lipopolysaccharide-stimulated RAW 264.7 cells, a widely used macrophage cell line. We observed that U. lactuca extract contained a relatively high total phenolic content (7.72 mg of gallic acid equivalents/g of extract) and exhibited multiple antioxidant activities including the scavenging of 2,2-diphenyl-1-picrylhydrazyl radical, hydroxyl, and superoxide anion radicals as well as reducing power. Simultaneously, we found that U. lactuca extract exhibited anti-inflammatory activity as evidenced by the reduction of nitric oxide in the U. lactuca extract-treated RAW 264.7 cells. Moreover, U. lactuca extract had a moderate inhibitory effect on α-amylase, although it showed no obvious inhibitory effect on α-glucosidase at the concentration tested. Collectively, our results demonstrated that the phenolic-enriched U. lactuca extract exhibited antioxidant and anti-inflammatory activities, and inhibited enzyme (α-amylase) relevant to hyperglycemia. Further research is required to determine the potential of developing the U. lactuca extract as a nutraceutical or pharmaceutical ingredient.