Black Lentil Water Extract Inhibited Inflammatory Cytokines in a Colitis-Associated Colon Carcinogenesis Model

Abstract

Abstract Objectives The objective was to compare the impact of black lentil water extract (BL) and delphinidin 3-O-(2-O-β-d-glucopyranosyl-α-l-arabinopyranoside) (D3G)-rich lentil extract on tumor development and inflammation in an azoxymethane (AOM)/dextran sodium sulfate (DSS) model. Methods C57BL/6 mice were randomly separated into four groups: healthy control (n = 6), AOM/DSS control (n = 14), AOM/DSS + BL (600 mg/kg body weight, n = 12), and AOM/DSS + D3G (41 mg/kg body weight, equivalent to D3G concentration in BL, n = 12). Mice were given treatments for 11 weeks using a voluntary oral jelly administration. Fecal samples were collected three times: after one week of treatments prior to the first AOM injection, after the first (of three) DSS cycle, and at the time of euthanasia. Secretory leukoprotease inhibitor (SLPI) expression was evaluated by qPCR, calprotectin by ELISA and fecal metabolite profiles by Agilent GC-MS system. Results AOM/DSS + BL presented a lower (p < 0.05) disease activity index, throughout and at the end (2.4) compared to AOM/DSS control (6.3). AOM/DSS + BL mice had an average of 7.8 neoplasms/mouse vs. 12.8 for the AOM/DSS (p < 0.05). Pro-inflammatory cytokines were downregulated in the colon mucosa in AOM/DSS + BL and AOM/DSS + D3G: interleukin 1β (−77.5%, −70.7%), interleukin 6 (−44.4%, −44.9%), respectively, compared to the AOM/DSS control. In non-polyp tissue, SLPI expression was higher compared to the healthy (1.0) and AOM/DSS control (5.0), AOM/DSS + BL (14.6) and AOM/DSS + D3G (10.3) groups. In polyp tissue, SLPI expression was highest in the AOM/DSS + BL group (24.3) versus the AOM/DSS control (9.3) and AOM/DSS + D3G (10.0). At the time of euthanasia, fecal calprotectin concentration was low for the healthy control (1.6 µg/g), AOM/DSS + BL (1.8 µg/g), and AOM/DSS + D3G (2.4 µg/g), but increased dramatically for the AOM/DSS control (4.1 µg/g) (p < 0.05). Gallic and protocatechuic acids and epicatechin were found in feces; the concentration of amino acids such as alanine, isoleucine, and leucine was lower, and unsaturated fatty acids were higher for AOM/DSS + BL and AOM/DSS + D3G versus the AOM/DSS control. Conclusions BL and D3G-rich extracts showed anti-inflammatory effects and modified fecal metabolites while BL additionally prevented growth of neoplasia. Funding Sources US Department of Agriculture Hatch 1,014,457.