Effects of aloperine on acute and inflammatory pain models in mice

•Aloperine suppresses hypersensitivity in mouse.•Aloperine reduces inflammatory pain.•Aloperine exerts analgesic effect by suppressing pro-inflammatory cytokines.

Background and objectivesAloperine (ALO) is an alkaloid compound and presents in several medicinal plants. This study was undertaken to investigate the anti-nociceptive and anti-inflammatory activities of ALO on various chemical- and thermal-induced hypersensitivity models in mice.MethodsThe anti-nociceptive effect of ALO was evaluated using acetic acid-induced writhing test, hot plate test, tail flick test, formalin test, ear swelling test, locomotor activity test, rota-rod test and carrageenan-induced paw edema test in mice. Inflammatory cytokines including interleukin-10 (IL-10), tumor necrosis factor α (TNF-α), interleukin-1 beta (IL-1β) and prostaglandin E2 (PGE2) expression were examined in ALO- and vehicle-treated mice.ResultsThe results showed that ALO significantly attenuated acetic acid-induced writhing numbers in mice in a dose-dependent manner. ALO showed no effect on prolonging latency in the hot plate test and the tail-flick test. ALO showed analgesic activity in the inflammatory phase of formalin-induced pain. Its anti-inflammatory effect was also confirmed in the ear-swelling test. In the carrageenan-induced paw edema model, ALO significantly and dose-dependently reduced the carrageenan-induced paw edema, decreased the contents of TNF-α, IL-1β and PGE2, but increased the IL-10 production. On the other hand, ALO showed no influence on the rota-rod performance time or on spontaneous locomotor activity.ConclusionIt is concluded that ALO has both anti-inflammatory and analgesic effects, especially in the field of inflammation pain.ImplicationsOur findings support the hypothesis that ALO ameliorates inflammatory pain induced by chemical and thermal stimuli and provides a scientific basis for the resource development and clinical use of aloperine.

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