Synergistic Herb-Herb Interaction of the Antinociceptive and Anti-Inflammatory Effects of and Combination.

The use of alternative medicine to treat pain has been increased, and the combination of several medicinal plants for its relief is a common practice in traditional medicine. The present study is aimed at determining whether a combination of () and L. () potentiates their antinociceptive and anti-inflammatory effects. These effects were explored using the formalin and carrageenan assays in rats, respectively. Animals received local pretreatment with oil or ethanolic extract (0.1-100 g/paw) alone or combined in a 1 : 1 rate. Concentration-response curves were built to compare pharmacological responses after an individual administration of , , or their combination. The pharmacological interaction was investigated by an isobolographic study using the EC of each component in a fixed 1 : 1 ratio. and administered alone showed significant and concentration-dependent antinociceptive and anti-inflammatory effects, but was more potent than in both the antinociceptive and anti-inflammatory effects (EC = 7.96 ± 0.6 g/paw vs. EC = 41.6 ± 1.7 g/paw; EC = 1.97 ± 0.3 g/paw vs. EC = 26.9 ± 2.5 g/paw, respectively). The isobolographic analysis of the combination of these species in a 1 : 1 ratio showed a synergistic interaction between and since (experimental value) was lower than (theoretical value) for both the antinociceptive effect (  = 0.45 ± 0.1 <   = 24.8 ± 1.3) and the anti-inflammatory effect (  = 5.2 ± 0.6 <   = 14.4 ± 2.2), suggesting a potentiation for both pharmacological effects. These results prove evidence of the efficacy of mixture herb-herb used in folk medicine for pain therapy. It also emphasizes the requirement of pharmacological studies to explore the efficacy and safety of herb interactions.