Analgesic Effects of Extracts on Postoperative, Neuropathic, and Menopausal Pain in Rat Models.

, widely cultivated in East Asia, has been reported to exhibit pharmacological efficacy in various disorders. However, little has been reported on its role as a pain killer. In this study, we reveal that the extract (COE) has great efficacy as a novel analgesic in various pain models. Administration of COE attenuated hypersensitivity in all postoperative, neuropathic, and menopausal pain models. Decreased hyperalgesia was confirmed by a mechanical withdrawal threshold assay and ultrasonic vocalization call analysis. In addition, application of COE inhibited the induction of the proinflammatory cytokines and calpain-3 on dorsal root ganglion neurons in a spared nerve injury rat model. Treatment with ferulic acid, which was identified as one of the components of COE by HPLC analysis, alleviated nociceptive behaviors. Our findings suggest that ferulic acid is an active compound from COE, and COE is a potential phytomedical source for pain relief by inhibiting the process of inflammation.