Inhibitory effects of Enteromorpha prolifera on the production of nitric oxide, prostaglandin E2, and pro-inflammatory cytokines in RAW 264.7 cells

Abstract

Inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 have been used as tools for the screening of anti-inflammatory agents. In a search for inhibitors of COX-2 and iNOS, we found that extracts of Enteromorpha prolifera inhibit the production of nitric oxide (NO) and prostaglandin (PG)E₂ in LPS-stimulated RAW 264.7 macrophage cells. We first extracted E. prolifera with 80% ethanol and the extract was partitioned with hexane, dichloromethane, ethyl acetate, butanol, and water, successively. The results indicate that the hexane and ethyl acetate fractions effective inhibited LPS-induced NO and PGE₂ production in RAW 264.7 cells. To test the inhibition effects of the E. prolifera fractions on other cytokines, we also performed an ELISA assay on tumor necrosis factor (TNF)-α, IL-1β, and IL-6 in LPS-stimulated RAW 264.7 macrophage cells. The expression of TNF-α, IL-1β, and IL-6 was also decreased following treatment with the hexane and ethyl acetate fractions. To test the potential application of the E. prolifera extract as a cosmetic material, we also performed MTT assays on keratinocyte HaCaT cells as well as primary skin irritation tests. In these assays, the E. prolifera extracts did not induce any adverse reactions. Based on these results, we suggest that E. prolifera extracts may be considered potential anti-inflammatory candidates for skin health.