Sesquiterpene lactones; Damsin and Neoambrosin suppress cytokine-mediated inflammation in complete Freund's adjuvant rat model via shutting Akt/ERK1/2/STAT3 signaling

Ethnopharmacologial relevance: Although Damsissa (Ambrosia maritima) is traditionally used as anti-inflammatory and diuretic, the biological activity and mechanism of action of its major constituents is to be elucidated.

Aim: to decipher the anti-arthritic potential of damsin and neoambrosin and to unfold their molecular signaling in complete Freund's adjuvant (CFA)-induced arthritis model.

Materials and methods: the right hind paw was inoculated with CFA (0.1 ml) at day 0 and 7 while treatments were started from the 14^th day and continued for 2 weeks. Rats were randomly assigned into 4 groups; normal group (NRML), CFA-induced arthritis group, CFA-induced arthritis treated with DMS and NMS (10 mg/kg/day) as 3^rd and 4^th group; respectively.

Results: Throughout experimental period, treatments ameliorated the increase of paw volume, knee joint diameter and nociception tests as reflected in open field arena. Also, DSM and NMS suppressed phosphorylation of Akt, STAT-3, ERK1/2 which was further mirrored by inactivation of GSK3β and downregulation of MCP-1 together with CCN1 and NF-kβ in hind paw tissue. Concomitantly, inflammation markers; TNF-α, IL-6, -12 were lowered as confirmed microscopically during examination of hind paw tissue.

Conclusion: DSM and NMS-induced suppression of NF-kβ subdues clinical features of RA most probably through repression of Akt/ERK1/2/STAT3 pathway. Therefore, DMS and NMS can serve as safe and effective treatment for rheumatoid arthritis, one of the most disabling chronic, inflammatory and painful autoimmune disease.

Keywords: Akt/ERK1/2/STAT3 pathway; Complete Freund’s Adjuvant; Damsin; Neoambrosin; Rheumatoid arthritis.