Antinociceptive, anti-inflammatory effects and acute toxicity of aqueous and ethanolic extracts of Myrtus communis L. Aerial parts in mice.

Myrtus communis L. aerial parts have been used in traditional medicine for the treatment of inflammatory disease. In this study 350 mice were divided into three main groups: negative (saline), positive (morphine or diclofenac) controls, and test groups. The acute toxicity was assessed for 2 days. Antinociceptive activity was performed using hot plate and writhing tests. The anti-inflammatory effect was investigated using xylene-induced ear edema and a cotton pellet test. According to phytochemical screening, the extracts contained tannins, alkaloids, and flavonoids. The LD50 values of the aqueous and ethanolic extracts were 0.473 and 0.79 g/kg, respectively. In hot plate test, the aqueous and ethanolic extracts showed significant antinociceptive activity that was inhibited by naloxone. The extracts exhibited antinociceptive activity against acetic acid-induced writhing and also showed significant activity against acute inflammation which was dose dependent for aqueous extract. The ethanolic (0.05 g/kg) and aqueous extracts (0.005, 0.015, and 0.03 g/kg) demonstrated anti-inflammatory effects against chronic inflammation. The aqueous and ethanolic extracts of the aerial parts of M communis L. showed antinociceptive effects and these may be mediated by opioid receptors.