Evaluation of anti-inflammatory and antinociceptive activities of Murraya exotica

Context: Leaves of Murraya exotica L. (Rutaceae) are used for the treatment of various disorders such as cough, fever, and infectious wounds, as well as alleviating pains in folk medicine in southern China. Objective: The objectives of this study were to investigate the in vivo antinociceptive and anti-inflammatory activities of ethanol (70%) extracts and isolated compounds obtained from the dried leaves of M. exotica. Materials and methods: The antinociceptive activities were evaluated with the methods of acetic acid-induced writhing response and hot-plate latent pain response test. Carrageenan induced hind paw edema, xylene induced ear edema, and a rat knee osteoarthritis model were employed to measure the anti-inflammatory activities. The compounds were isolated using column chromatography and thin-layer chromatography, and the structures identified by H-1 NMR, C-13 NMR, MS, and IR. Results: The ethanol (70%) extracts significantly decreased in the acetic acid-induced writhing response; increased in hot-plate latency; suppressed xylene induced ear swelling and the carrageenan-induced paw edema effectively. In the rat knee osteoarthritis model, the treatment of the ethanol (70%) extracts resulted in a significant increase in the activity of superoxide dismutase, an inhibition on inducible nitric oxide synthase activity, and a decrease in the contents of interleukin-1 beta and tumor necrosis factor-alpha of the rat serum. Following this, we explored the components of the ethanol (70%) extracts and isolated six known coumarins, including murracarpin, which exhibited the most potential in antinociceptive and anti-inflammatory activities. Discussion and conclusion: M. exotica displayed remarkable antinociceptive and anti-inflammatory activities.