Ziziphora clinopodioides ameliorated rheumatoid arthritis and inflammatory paw edema in different models of acute and chronic inflammation.

Ziziphora clinopodioides has been used in traditional medicine for its anti-inflammatory properties. Current study is believed to first time report the potential of Z. clinopodioides extracts to ameliorate joint inflammation using model of chronic joint inflammation (FCA-induced rheumatoid arthritis). The study further investigates the effects on joint inflammation using acute inflammatory paw edema models. The anti-inflammatory effects were also supported by using xylene-induced ear edema model. Results showed that Z. clinopodioides significantly ameliorated rheumatoid arthritis as indicated by the inhibition of arthritic development and paw edema. Histopathological examination showed significant attenuation in pannus formation, bone erosion, and joint inflammation. Treatment with the plant extracts also nearly normalized counts of RBCs, platelets, and total leukocytes along with hemoglobin (Hb) content. Biochemical analysis (AST, ALT, urea, and creatinine) showed that plant extracts did not possess hepatotoxic or nephrotoxic effects. Water displacement plethysmometric analysis showed that Z. clinopodioides significantly attenuated carrageenan-induced paw edema. To evaluate the mechanism, anti-inflammatory effects were further evaluated using histamine- and serotonin-induced inflammatory paw edema models. Z. clinopodioides significantly suppressed paw edema induced by both histamine and serotonin, and also caused the inhibition of xylene-induced ear edema. This suggested the inhibition of autacoids as one of the mechanisms of anti-inflammatory effects of plant. GC-MS analysis showed that the plant is rich in essential oils, including terpenoids, esters, alcohols, furans, cyclic ketones, epoxides, oxanes, and acyclic hydrocarbons. In conclusion, current study demonstrated that Z. clinopodioides possessed significant anti-arthritic and anti-inflammatory properties which might be attributed to the inhibition of autacoids.