Abstract

Neuropathic pain (NP) is a common condition accompanied by nerve injury. To date, there is no definite treatment approved for this disorder. In addition, many drugs that are used for NP cause adverse reactions. Luteolin is a naturally occurring flavonoid with diverse pharmacological properties such as anti-inflammatory, antioxidant and anticancer. We sought to investigate luteolin effects on chronic, acute and neuropathic pain as well as its potential to increase morphine anti-nociceptive effects in mice. Albino mice (20-25g) were randomly divided into 14 groups (n=7) including morphine 1mg/kg body weight +luteolin (5mg/kg body weight), morphine (9mg/kg body weight, i.p.), luteolin (2.5, 5 and 10mg/kg body weight), imipramine 40mg/kg body weight and normal saline (NS) (0.9) as vehicle and subjected to hot plate test. Formalin test was done in the following groups: NS, diclofenac sodium (10mg/kg body weight, i.p.), morphine (9mg/kg body weight, i.p.) and luteolin (2.5, 5 and 10mg/kg body weight). Administration of luteolin single dose (5 and 10mg/kg body weight) significantly reduced neuropathic pain (p < 0.05) in comparison to negative control. Anti-nociceptive effects of luteolin were comparable to imipramine as the standard positive control (p < 0.001). Co-administration of luteolin and morphine potentiated morphine 1mg/kg body weight painkilling effects (p <0.001). Our results showed that luteolin alone reduces neuropathic pain. Furthermore, when co-administered with morphine 1mg/kg body weight, luteolin potentiates morphine effects. Therefore, luteolin-morphine co-administration might be a valuable alternative for the conventional treatment. © 2017 Walter de Gruyter GmbH, Berlin/Boston.