Monnieriside A from Evolvulus linarioides promotes antinociceptive effects in models of inflammatory and postoperative pain in male mice.

Monnieriside A (MoA) is a chromone isolated from Evolvulus linarioides. This study investigated the antinociceptive potential of MoA in mice. MoA (0.01-100 mg/kg, i.p.) inhibited nociception in the inflammatory phase of the formalin test without causing motor impairment. MoA (0.1-100 mg/kg, i.p.) also reduced hindpaw mechanical allodynia caused by either intraplantar injection of Complete Freund's Adjuvant (CFA) or surgical paw incision to simulate postoperative pain. Postoperative antinociception was accompanied by reduced IL-1β levels in the incised paw, assessed by ELISA. The antinociceptive action of MoA (100 mg/kg, i.p.) was preserved in IL-10 knockout mice submitted to paw incision, indicating that IL-10 is not essential to the antinociceptive effect. Interestingly, MoA (100 mg/kg, i.p.) increased the expression of TGF-β in IL-10 knockout mice, which could be a compensation mechanism leading to an antinociceptive effect in the absence of IL-10.