Antinociceptive synergistic interaction between Achillea millefolium and Origanum vulgare L. extract encapsulated in liposome in rat

Aim: This study aims to evaluate the antinociceptive effect of combined Achillea millefolium and Origanum extract encapsulated in liposome. Methods: The effect of Achillea millefolium and Origanum vulgare L. extract, and their liposome-incorporated form was assessed using 3% formalin test in rat. 12 male Wistar rats, 4 in each group, were used in this study, and increasing doses of Achillea millefolium (31.6, 100, 178, and 316mg/kg) and Origanum vulgare L. extract (5.6, 10, 17.8, and 31.6 mg/kg), and co-administered extract were i.p. administered 10 min before 3% formalin. The mechanisms of action were evaluated for the liposomal encapsulated co-administered extract using N(G)-nitro-L-arginine methyl ester (L-NAME) (3mg/kg) and naloxone (1 mg/kg). Results: The interaction index and isobolographic analysis revealed a synergistic effect of the extracts. We observed a lower experimental ED30 as compared to the theoretical ED30. Naloxone also reduced the antinociceptive effect of the liposome encapsulated co-administered extract. Conclusion: These data suggest that the Achillea millefolium and Origanum vulgare L. extract encapsulated in liposome gave a synergistic effect.