Naringin protects against dextran sodium sulfate-induced colitis in mice

Naringin (4′,5,7-trihydroxyflavanone 7-rhamnoglucoside) is a well-known natural flavonoid that acts as a potent anti-oxidant, superoxide scavenging, anti-apoptotic, anti-atherogenic and metal chelating agent [1]. Orally administered naringin is metabolized to its aglycone, naringenin, which has a wide range of pharmacological properties, including an anti-inflammatory effect through inhibition of nitric oxide and prostaglandin E2 production [2]. The aim of this study is to determine the effect of naringin on a model of inflammatory bowel disease (IBD), namely dextran sulfate sodium (DSS)-induced colitis in mice. Female Balb-C mice were randomized to receive either normal water or 5% DSS drinking water to induce colitis. The mice were fed a control diet or a diet supplemented with 2% naringin or 2% rutin for 7 days [3,4]. On day 8, the mice were sacrificed and their colons were removed, immediately snap-frozen on liquid nitrogen and stored until use. The disease activity index score (DAI) was analyzed taking weight loss as well as stool blood and rectal bleeding into consideration. The removed colons were subjected to protein extraction and COX-2 expression was analyzed with the aid of Western blot techniques. Naringin was found to significantly reduce the extent and severity of injury to the colon as shown by the DAI score (49% reduction), colon length (40% reduction vs. blank) and COX-2 levels (78% inhibition). Rutin, a polyphenolic flavonoid used as reference, also diminished these parameters by percentages of 60, 42 and 75, respectively. These results indicate that naringin may prove to be a useful agent for treating IBD.