Charantin relieves pain by inhibiting pro-inflammatory cytokine induction

Background: The fruits of Momordica charantia, commonly known as bitter melon, have been used as a traditional medicine in several countries. Some studies have reported its pharmacological effects in various disorders. Objectives: Because there have been little reports on charantin's role as an analgesic, we evaluated its pain relief effect to determine if it could be a novel pain killer candidate. Materials and Methods: We established post-operative and neuropathic pain models, which represent acute and chronic pain, respectively. Mechanical withdrawal threshold assay and ultrasonic vocalization analysis were used as behavioral tests. Results: The administration of charantin reduced both the post-operative and neuropathic pain. The application of charantin did not make a difference in the activation of action potentials of dorsal root ganglion (DRG) neurons. However, charantin inhibited the induction of the pro-inflammatory cytokines interleukin IL-12 and IL-1β in DRG neurons. Conclusion: Our findings indicate that charantin seems to relieve pain by inhibiting the inflammatory process rather than by directly influencing the activity of neurons. We conclude that charantin, the commercially available extract from M. charantia, has great efficacy as a novel analgesic compound.