Synergistic Interaction of Matricaria Chamomilla Extract with Diclofenac and Indomethacin on Carrageenan-Induced Paw Inflammation in Rats.

Preclinical Research The coadministration of non-steroidal anti-inflammatory drugs (NSAIDs) with medicinal plant extracts may increase anti-inflammatory activity, thus permitting the use of lower NSAID doses and limiting the side effects. The aim of this study was to explore the interactions between an ethanolic extract of M. chamomilla extract (MCE) with two NSAIDs, diclofenac and indomethacin on carrageenan-induced paw inflammation and gastric injury in rats. Diclofenac, indomethacin and MCE, or combinations with MCE produced an anti-inflammatory effect. Effective dose (ED) values were estimated for the individual drugs, and isobolograms were constructed. The final experimental ED values were 483.7 mg/kg for diclofenac + MCE combination, and 212.6 mg/kg for indomethacin + MCE. These values were lower (p < 0.05) than the theoretical ED values (1186.9 mg/kg for diclofenac + MCE combination, and 1183.8 mg/kg for indomethacin + MCE). These data suggest that the interactions between NSAIDs and MCE that mediate the anti-inflammatory effects at the systemic level are synergistic and may have therapeutic advantages for the clinical treatment of inflammatory processes. Drug Dev Res 78 : 360-367, 2017. © 2017 Wiley Periodicals, Inc.

Isolation, identification and molecular docking as cyclooxygenase (COX) inhibitors of the main constituents of Matricaria chamomilla L. extract and its synergistic interaction with diclofenac on nociception and gastric damage in rats.

Chamomile (Matricaria chamomilla L., Asteraceae) is a medicinal plant widely used as remedy for pain and gastric disorders. The association of non-steroidal anti-inflammatory drugs (NSAIDs) with medicinal plant extracts may increase its antinociceptive activity, permit the use of lower doses and limit side effects. The aim was to isolate and identify the main chemical constituents of Matricaria chamomilla ethanolic extract (MCE) as well as to explore their activity as cyclooxygenase (COX) inhibitors in silico; besides, to examine the interaction between MCE and diclofenac on nociception in the formalin test by isobolographic analysis, and to determine the level of gastric injury in rats. Three terpenoids, α-bisabolol, bisabolol oxide A, and guaiazulene, were isolated and identified by (1)H NMR. Docking simulation predicted COX inhibitory activity for those terpenoids. Diclofenac, MCE, or their combinations produced an antinociceptive effect. The sole administration of diclofenac and the highest combined dose diclofenac-MCE produced significant a gastric damage, but that effect was not seen with MCE alone. An isobologram was constructed and the derived theoretical ED35 for the antinociceptive effect was significantly different from the experimental ED35; hence, the interaction between diclofenac and MCE that mediates the antinociceptive effect is synergist. The MCE contains three major terpenoids with plausible COX inhibitory activity in silico, but α-bisabolol showed the highest affinity. Data suggest that the diclofenac-MCE combination can interact at the systemic level in a synergic manner and may have therapeutic advantages for the clinical treatment of inflammatory pain.