Morphine versus apigenin-induced antinociception in rodent models- A randomised comparative study

Abstract

Apigenin a plant-derived flavone with anti-inflammatory and antioxidant properties. Therefore, it is of interest to evaluate the antinociceptive activities in the acetic acid–induced writhing test in the rats and compared with morphine while assessing opioid receptor involvement using naloxone. Twenty-four Wistar rats were divided into four groups (n = 6): control, morphine (5 mg/kg, S.C.), apigenin (20 mg/kg, p.o.), and naloxone (5 mg/kg, i.p.) plus apigenin, and writhing responses were recorded 5–20 min after intraperitoneal injection of 0.6% acetic acid. Morphine significantly reduced writhing counts at all-time points compared with control (p < 0.001), whereas apigenin produced modest antinociceptive activity and the naloxone + apigenin group showed intermediate effects. Repeated-measures and one-way ANOVA demonstrated significant within and between group differences (p < 0.001). Thus, data shows that apigenin exerts mild antinociceptive effects that are largely independent of predominant μ-opioid receptor mediation.