The Antinociceptive Effects of Hydroalcoholic Extract of Bryonia dioica in Male Rats

Background: Side effects of synthetic analgesic drugs in the clinical practice have drawn researchers’ attention on developing the herbal medicine as more appropriate analgesic agents. Objectives: This study aimed to investigate the antinociceptive effect of hydroalcoholic leaf extract of Bryonia dioica (HEBD) on male rats. Materials and Methods: In this experimental study, 42 adult male rats were divided into 7 groups: control, HEBD (80, 100, and 300 mg/ kg, ip), morphine (1 mg/kg, ip), indomethacin (1 mg/kg, ip), and naloxone (1 mg/kg ip). In order to assess the analgesic effects of the extract, writhing, tail-flick, and formalin tests were used. Also, Tukey post hoc and 1-way analysis of variance (ANOVA) tests were used to analyze the data. Results: Using writhing, tail-flick, and formalin tests, dramatic antinociceptive effects were observed for HEBD at the dose of 300 mg/kg with P < 0.01. The results of data analysis also revealed that there was no significant difference between indomethacin and dose of 300 mg/ kg of extract in formalin test. LD50 of the plant was 4200 mg/kg. Conclusions: The experimental data verified that HEBD leaves displayed remarkable antinociceptive activity. Furthermore, the nonselective opioid receptor antagonist, naloxone blocked the antinociceptive effect of the extract in all tests, suggesting that HEBD may act both at peripheral and central levels.