Anti-inflammatory Activity of Myricetin Isolated from Myrica rubra Sieb. et Zucc. Leaves

Myrica rubra Sieb. et Zucc. leaves are commonly used in folk medicine to treat inflammatory disorders in China. Present studies on the anti-inflammatory effect of myricetin from Myrica rubra Sieb. et Zucc. leaves was evaluated with various in vivo models of both acute and chronic inflammations such as xylene-induced ear edema, acetic acid-induced vascular permeability, carrageenan-induced paw edema, leukocyte migration assay, and cotton pellet granuloma models. Myricetin showed a significant inhibition on ear edema and hind paw edema caused by xylene and carrageenan, respectively. Furthermore, it also inhibited the increase in capillary permeability induced by the production of acetic acid in the human body. Myricetin significantly decreased the serum levels of MDA and, in turn, increased the serum levels of SOD in the carrageenan-induced paw edema model. Concurrently, myricetin also significantly decreased leukocyte count. During chronic inflammation, myricetin inhibited the formation of granuloma tissue. These results, collectively, demonstrate that myricetin possesses a potent anti-inflammatory function on acute and chronic inflammation. Its anti-inflammatory mechanisms are probably associated with the inhibition of antioxidant activity. These results also support the claims of traditional Chinese medicine practitioners about the use of Myrica rubra Sieb. et Zucc. leaves in the treatment of inflammatory diseases.