Chrysophyllum albidum fruit peel attenuates nociceptive pain and inflammatory response in rodents by inhibition of pro-inflammatory cytokines and COX-2 expression through suppression of NF-κB activation

Abstract

Chrysophyllum abidum fruit is a seasonal fruit commonly eaten as snacks with abundant health promoting phytochemicals in the fruit peels. The fruit peels have been reported to be rich in anti-inflammatory eleagnine, myricetin rhamnoside, quercetin, linoleic acid and oleic acid. We hypothesized that the anti-inflammatory effect of the peel extract involve suppression of pro-inflammatory cytokines, cyclooxygenase-2 and nuclear factor-kappa B (NF-κB). Hence, this study was designed to assess the anti-nociceptive and anti-inflammatory effects of fruit peel extract of Chrysophyllum albidum in animal models of nociception and inflammation. The anti-nociceptive activity of CAPEE (100 and 400 mg/kg) was evaluated in acetic acid-induced writhing and formalin-induced paw licking in mice. Formalin-induced paw edema and carrageenan-induced air pouch models of inflammation were used to evaluate the anti-inflammatory activity. CAPEE (100 and 400 mg/kg) significantly reduced abdominal writhing and paw licking in acetic acid and formalin tests in mice, respectively. CAPEE demonstrated significant inhibition of paw edema at 24 h (41.0% and 55.7%) and 72 h (52.3% and 86.6%) after formalin injection. CAPEE suppressed inflammatory responses in carrageenan-induced air pouch by reducing exudates, inflammatory cells infiltration, nitrites and myeloperoxidase activity. There was significant inhibition of tumor necrosis factor-alpha, interleukin-6 levels and reduced immunopositive expression of COX-2 and NF-κB. In conclusion, CAPEE has anti-nociceptive and anti-inflammatory potentials via mechanisms associated with inhibition of pro-inflammatory cytokines and cyclooxygenase-2 (COX-2) expression through suppression of nuclear factor kappa B (NF-κB) activation, and has potential as a functional food ingredient.

Keywords: Carrageenan model; Cyclooxygenase-2; Nuclear factor kappa B; Star apple; Tumor necrosis factor-alpha.