Backgrounds: Inula helenium L. is an herb with anti-inflammatory properties. Sesquiterpene lactones (SLs), mainly alantolactone (AL) and isoalantolactone (IAL), are considered as its active ingredients. However, the anti-inflammatory effects of SL-containing extracts of I. helenium have not been explored. Here we prepared total SLs from I. helenium (TSL-IHL), analyzed its chemical constituents, and performed cellular and animal studies to evaluate its anti-inflammatory activities.
Materials and methods: The chemical profile of TSL-IHL was analyzed by HPLC-UV. Its in vitro effects on the activation of signaling pathways and expression of inflammatory genes were examined by western blotting and quantitative real-time PCR, respectively, and compared with those of AL and IAL. Its in vivo anti-inflammatory effects were evaluated in adjuvant- and collagen-induced arthritis rat models.
Results: Chemical analysis showed that AL and IAL represent major constituents of TSL-IHL. TSL-IHL, as well as AL and IAL, could inhibit TNF-α-induced activation of NF-κB and MAPK pathways in b. End3 cells, suppress the expressions of MMP-3, MCP-1, and IL-1 in TNF-α-stimulated synovial fibroblasts, and IL-1, IL-6, and iNOS in LPS-activated RAW 264.7 cells in a dose-dependent manner in the range of 0.6–2.4μg/mL. Oral administration of TSL-IHL at 12.5−50 mg/kg could dose-dependently alleviate the arthritic severity and paw swelling in either developing or developed phases of arthritis of rats induced by adjuvant or collagen.
Conclusions: These results indicated potentials of TSL-IHL in prevention and therapy of rheumatoid arthritis.