GC/MS analysis and anti-inflammatory effect of leaf extracts from Hibiscus syriacus through inhibition of NF-κB and MAPKs signaling in LPS-stimulated RAW264.7 macrophages

Hibiscus syriacus (H. syriacus), which belongs to Malvaceae, is a perennial herb widely distributed in East Asia. In this study, we investigated the anti-inflammatory effects and its potential molecular mechanisms of leaves extracted with 70% ethanol of H. syriacus (HS-L) at the mRNA and protein level when RAW264.7 macrophages were stimulated by LPS. HS-L dose dependently (0, 25, 50, 100 μg/mL) reduced NO production by inhibiting iNOS, COX-2, and IL-β expression in LPS-induced RAW264.7 macrophages. HS-L decreased the LPS-stimulated degradation and phosphorylation of IkB-a. Moreover, treatment with HS-L suppressed LPS-induced DNA binding of NF-kB and nuclear translocation of p65. Furthermore, HS-L suppressed the phosphorylation of ERK1/2 and p38. HS-L was analyzed to contain compounds such as 2-pentadecanone, methyl palmitate, and ethyl palmitate in GC/MS analysis. These results suggested that HS-L could utilize anti-inflammatory activity by inhibiting NF-κB and MAPKs signaling pathways and that HS-L could be used as a natural anti-inflammatory agent.