Black Lentil Aqueous Extract Attenuates Colitis-Associated Colon Carcinogenesis in Mice (OR04-06-19).

Objectives: The objective was to compare the efficacy of a black lentil aqueous extract (BL) and a semi-purified anthocyanin (ANC) extract to prevent tumor development and inflammatory processes and impact on immune response in an azoxymethane (AOM)/dextran sodium sulfate (DSS) mouse model.

Methods: BL was obtained from an overnight soak of organic beluga black lentils (1:2 w/v) in water, filtered, frozen, and freeze-dried. The major ANC identified was delphinidin 3- O -(2-O-β-d-glucopyranosyl-α-l-arabinopyranoside (D3G). Seven and a half week old C57BL/6 mice were randomly separated into four groups: healthy control ( n  = 6), disease control ( n  = 14), BL ( n  = 12), and D3G ( n  = 12). After a one week acclimation, the mice were given treatments for 11 weeks, either placebo or BL: 600 or D3G: 41 mg/kg body weight (equivalent to D3G in a BL extract) using a voluntary jelly administration every morning throughout the study. Following the first week of treatments, mice received an AOM injection of 10 mg/kg body weight. Three cycles of DSS in water started one week later. The first cycle had 2% DSS for one week; the second and third cycles had 1%. Each cycle had two weeks of regular water post-DSS. Inflammation, progression, and immune markers were analyzed in the colon, spleen, and plasma by histology, gene expression, ELISA, and protein arrays.

Results: BL had total ANC concentration of 21.3 mg D3G equivalent/g dry extract and total polyphenol concentration of 264.9 mg gallic acid equivalent/g dry extract. BL group had a lower disease activity index (DAI), throughout and at the end, of 2.4 compared to 6.3 of the disease control and 4.0 of D3G group ( P  < 0.05). Mice in the BL group had an average of 7.8 neoplasms while the disease control had 12.8 and D3G had 12.1 ( P  < 0.05). BL group had a lower relative spleen weight and colon weight to length at 5 and 59 mg/cm compared to 10 and 82 mg/cm and 10 and 83 mg/cm of the disease control and D3G groups, respectively ( P  < 0.05). Based on colon cancer cell results, BL lowered expression of inhibitory immune markers, like PD-L1 ( P  < 0.05).

Conclusions: BL attenuated the DAI and helped mice maintain their weight throughout the AOM/DSS treatment. BL also resulted in a lower total and lower large neoplasm number, relative lower spleen weight, and colon weight to length ratio compared to the disease control. BL showed anti-carcinogenic anti-inflammatory properties.

Funding Sources: USDA-NIFA-HATCH project 1014457.