Evaluation of mitragyna speciosa analgesic activity in mice / Salina Mohd Saad

The leaves of mitragyna spectosa (Rubiaceae) have been traditionally used as substitute for opium. Mitragynine is a major alkaloid constituent that is known to produce opioid like action when smoked, chewed or drunk. This study is done to evaluate analgesic properties of mitragyna speciosa in mice. Investigation of the antinociceptive activity of intraperitoneal (i.p) injection of saline, Mitragyna speciosa extract (l5mg/kg, 25mg/kg and 35mg/kg) and acetaminophen (35mg/kg) was done by using hot-plate test. The mice was placed on a metal plate maintained 55 ± 0.5°C and latency to show nociceptive responses such as hind paw licking, hind paw flicking or jumping was measured 5 minutes prior dosing and every 10 minutes over 80 minutes after dosing. Mitragyna speciosa showed increase in latency reaction compare to saline (control). However the results were not statistically significant .The test did not exhibit a dose dependent pattern. The latency time of mitragyna speciosa 15mg/kg was longer than Mitragyna speciosa 35mg/kg. Mitragyna speciosa may be a potential new analgesic. Nevertheless further studies need to be carried out in future to more understand its pharmacological properties.