Anti-oxidant, anti-inflammatory and anti-melanogenesis effects of Narcissus extracts

Abstract

The present study was performed to evaluate the inhibitory activity of extracts of Narcissus tazetta var. Chinensis on inflammation in RAW 264.7 and melanin synthesis in B16-F10 melanoma cells. Functional effects of Narcissus flower extract (NFE), Narcissus stem extract (NSE), and Narcissus root extract (NRE) were analyzed. Narcissus extracts (NE) displayed DPPH free radical scavenging activity in a dose-dependent manner. Based on cell viability assay, NFE, NSE and NRE had no cytotoxicity up to 10, 4, 20 μg/mL concentrations in RAW 264.7 cells and 20, 5, 20 μg/mL concentrations in B16-F10 melanoma cells respectively. Based on Western blot analysis, NE significantly inhibited the production of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein expression levels, with concomitant reductions in the production of nitric oxide (NO) in LPS stimulated RAW 264.7 cells. In addition, NE inhibited pro-inflammatory cytokine levels including TNF-α, IL-1β, and IL-6 in LPS stimulated RAW 264.7 cells. NE inhibited both melanin synthesis and tyrosinase activity in α-MSH stimulated B16-F10 melanoma cells in a dose dependent manner. RNA sequencing analysis showed differential gene expression patterns in genes related to immune response, inflammatory response and antioxidant activity in LPS stimulated RAW 264.7 macrophage cells. LPS stimulated differentially expressed 39 genes related to inflammatory response including NF-κB2, AXL, APOE, LDL, TLR4, NF-κB1, IFNB1, IRAK2, NR1H4, Cxcr2, Cxcr6, Ccl28 and Cxcl9 were normalized to the control level by each NE. Overall results suggest that NE scavenged DPPH free radicles dose dependently, exhibited anti-inflammatory effects via attenuating iNOS, COX-2 protein expression, TNF-α, IL-6 and IL-1β pro-inflammatory cytokines expression and normalizing the expression of genes related to inflammation which were perturbed by LPS in RAW 264.7 macrophage cells, and showed anti-melanogenesis effects on α-MSH stimulated B16-F10 melanoma cells by suppressing the cellular tyrosinase activity and melanin synthesis in B16-F10 melanoma cells. Bioactive compounds in NE can be applied for the development of anti-inflammatory drugs in pharmaceutical industry and for the development of anti-melanogenesis drugs in cosmetic industry.