HO-1 Induction by Selaginella tamariscina Extract Inhibits Inflammatory Response in Lipopolysaccharide-Stimulated RAW 264.7 Macrophages

Selaginella Herba is the dried, aerial part of Selaginella tamariscina (P.Beauv.) Spring and has been used to treat amenorrhea, abdominal pain, headaches, and hematuria in Korea. However, scientific evidence regarding the anti-inflammatory activity and action mechanism of Selaginella tamariscina is lacking. Thus, the present study was performed to investigate the anti-inflammatory and antioxidant activities of Selaginella tamariscina ethanol extract (STE) against lipopolysaccharide (LPS)-induced inflammatory responses and identify the molecular mechanism responsible. STE was prepared by heating in 70% ethanol and its quality was confirmed by HPLC. STE dose-dependently inhibited the productions of inflammatory mediators (NO and PGE(2)) and proinflammatory cytokines (IL-1β and IL-6) in LPS-stimulated RAW 264.7 cells. STE markedly suppressed the phosphorylations of MAPKs, IκB-α, and NF-κB and the nuclear translocation of NF-κB induced by LPS stimulation. In addition, STE exhibited good free radical scavenging activity and prevented ROS generation by LPS. STE also upregulated the expression of Nrf2 and HO-1 and promoted the nuclear translocation of Nrf2. Taken together, STE was found to have anti-inflammatory and antioxidant effects on RAW 264.7 macrophages and the mechanism appeared to involve the MAPK, NF-κB, and Nrf2/HO-1 signaling pathways. These results suggest that STE might be useful for preventing or treating inflammatory diseases and provide scientific evidence that supports the developments of herbal prescriptions or novel natural products.