Anti-hyperalgesic properties of ethanolic crude extract from the peels of Citrus reticulata (Rutaceae)

Abstract

The therapeutic effects from Citrus reticulata on painful infl ammatory ailments are associated to its fl avonoids constituent and phytochemical studies with Citrus genus affi rm that the peels have important amounts of it. These bioactive compounds have been a considerable therapeutic source and evaluate potential application of the peel extract is signifi cant. This research aims to investigate the infl uence of ethanolic crude extract from the peels of Citrus reticulata and its possible mechanism of action in different animal models of pain. The extract reduced hyperalgesia in the second phase of formalin test (vehicle: 501.5 ± 40.0 s; C. reticulata extract 300 mg/kg: 161.8 ± 41.1 s), in the carrageenan model (vehicle at 4 th h: 82.5 ± 9.6 %; C. reticulata extract 300 mg/kg at 4 th h: 47.5 ± 6.5 %) and in Complete Freund's Adjuvant model (vehicle: 501.5 ± 40.0 s; C. reticulata extract 300 mg/kg: 161.8 ± 41.1 s). The possible contribution of opioidergic and adenosinergic systems in the anti-hyperalgesic effect of C. reticulata extract was observed after treatment, with non-selective antagonists for both systems, which produced reversal effects. In conclusion, these properties of C. reticulata extract suggest a potential therapeutic benefi t in treating painful conditions.