Investigation of the effect of phlomisoside F on complete Freund's adjuvant-induced arthritis.

Phlomis younghusbandii Mukerjee (Labiatae) has been reported to be effective in the treatment of rheumatoid arthritis (RA). In the present study, the anti-inflammatory and anti-arthritic effects of phlomisoside F (PF), isolated from P. younghusbandii Mukerjee (Labiatae), were investigated in male Wistar rats subjected to carrageen-induced paw edema and complete Freund's adjuvant (CFA)-induced arthritis. Arthritis scores were evaluated by a 5-point ordinal scale (scores 0-4). Expression levels of TNF-α, IL-1β, IL-6, IL-10, COX-2 and 5-LOX were determined via ELISA and western blot assays. Subsequent to establishing the edema and arthritis models, oral administration of PF (5, 10 and 20 mg/kg) significantly inhibited mean edema rate, compared with the control group in carrageenan-induced paw edema assay. In addition, administration of PF (5, 10 and 20 mg/kg/day) for 28 days markedly exhibited an anti-arthritic activity by offsetting the body weight loss, inhibiting the paw edema, reducing the arthritis scores and the indices of thymus and spleen, inhibiting the expression levels of TNF-α, IL-1β, IL-6, COX-2 and 5-LOX, and increasing the expression of IL-10, when compared with the respective control group in CFA-induced arthritis assay. In conclusion, PF is a valuable anti-arthritic constituent of P. younghusbandii, and the present study results suggest that this herb may be used in the treatment of RA.