Anti-inflammatory activity of taro-derived resistant starch and its effect on the intestinal flora

Taro (Colocasia esculenta (L.) Schott) is classified as an herbaceous root crop with a high starch content. No studies have been reported on the modulatory effects of taro-derived resistant starch (TRS) on intestinal inflammation and the gut microbiota. In this study, TRS with a concentration of 69.81% wt. was prepared from taro starch and its physicochemical and structural properties were evaluated by using SEM, FTIR, and XRD. The molecular degree of order (R1047/1022cm^-1) of the TRS was 0.915, while the degree of double-helix (R995/1022cm^-1) was 1.041. TRS exhibited the most prominent diffraction peak, observed at 17.0°, which is characteristic of type B crystallization. All animal studies were approved by the Experimental Animal Ethics Committee of Yangzhou University (license number SYXK2016-0019). The administration of 300 mg/kg TRS reduced colon shortening and alleviated colonic mucosal injury in colitis mice, thus reducing the infiltration of inflammatory cells. Compared to the DSS group, the levels of IL-6, TNF-α, and MDA were decreased in the DSS+TRS group, while the levels of IL-10, T-AOC, SOD, and CAT were increased, indicating that TRS enhanced the anti-inflammatory response. It is noteworthy that TRS restored the reduction in gut microbiota diversity and abundance caused by DSS-induced colitis in mice, while also reducing the abundance of potentially harmful bacteria, namely Desulfovibrio, norank_f_Desulfovibrionaceae, and norank_f_norank_o_Clostridia_UCG-014. Conversely, the prevalence of beneficial bacteria, such as Lactobacillus and norank_f_Muribaculaceae, was increased. Concomitantly, TRS treatment significantly increased the production of short-chain fatty acids, including acetate, propionate, and butyrate, in colitis mice. This was found to be positively correlated with the reinforcement of beneficial gut microbiota by TRS. These studies have demonstrated that TRS can attenuate the progression of colitis and is a promising candidate for the development of a new prebiotic treatment for ulcerative colitis.