Pimenta pseudocaryophyllus (Gomes) Landrum extract inhibits inflammatory pain in mice: targeting neutrophil recruitment, oxidative stress, and cytokine production.

Pimenta pseudocaryophyllus (Gomes) Landrum is a Brazilian native plant. The mechanisms by which it promotes analgesia are unknown. We demonstrated the analgesic effect of P. pseudocaryophyllus dried extract (3 mg/kg; i.p.) in the following models of inflammatory pain (maximal inhibition): phenyl-p-benzoquinone (89%), formalin (72% - 1st phase and 96% - 2nd phase for flinches, and 50% - 1st phase and 71% - 2nd phase for licking behavior), complete Freund's adjuvant (95% - flinches and 33% - licking behavior), and carrageenin (56% - mechanical and 85% - thermal hyperalgesia) without motor impairment. Its analgesic effect depends on inhibiting neutrophil recruitment (95% - histopathology, 83% - myeloperoxidase activity, and 80% - LysM-eGFP mice), oxidative stress (86% - GSH and 98% - superoxide anion), and cytokine production (35% - IL-33, 80% - TNF-α, and 95% - IL-1β). The present study advances in understanding the analgesic mechanisms of P. pseudocaryophyllus .