Diets rich in fruits and vegetables may reduce oxidative stress (OxS) and
inflammation via several mechanisms. These beneficial effects may be due to their high
polyphenol content. The aims of the present study are to evaluate the preventive and therapeutic aspects of
polyphenols in dried apple peel
powder (
DAPP) on intestinal
inflammation while elucidating the underlying mechanisms and clinical benefits. Induction of intestinal
inflammation in mice was performed by
oral administration of the inflammatory agent
dextran sulfate sodium (DSS) at 2.5% for 10 days. Physiological and supraphysiological doses of
DAPP (200 and 400 mg/kg/day respectively) were administered by gavage for 10 days pre- and post-DSS treatment. DSS-mediated
inflammation caused
weight loss, shortening of the colon, dystrophic detachment of the epithelium, and infiltration of mono- and poly-morphonuclear cells in the colon. DSS induced an increase in lipid peroxidation, a down-regulation of
antioxidant enzymes, an augmented expression of
myeloperoxidase (MPO) and
cyclooxygenase-2 (COX-2), an elevated production of
prostaglandin E2 (
PGE2) and a shift in mucosa-associated microbial composition. However,
DAPP normalized most of these abnormalities in preventive or therapeutic situations in addition to lowering inflammatory
cytokines while stimulating
antioxidant transcription factors and modulating other potential healing pathways. The supraphysiological dose of
DAPP in therapeutic situations also improved
mitochondrial dysfunction. Relative abundance of Peptostreptococcaceae and Enterobacteriaceae bacteria was slightly decreased in
DAPP-treated mice. In conclusion,
DAPP exhibits powerful
antioxidant and anti-inflammatory action in the intestine and is associated with the regulation of cellular signalling pathways and changes in microbiota composition. Evaluation of preventive and
therapeutic effects of
DAPP may be clinically feasible in individuals with intestinal
inflammatory bowel diseases.