Recent studies have suggested that flavonoids such as quercetin and probiotics such as Bifidobacterium bifidum (Bf) and Lactobacillus gasseri (Lg) could play a relevant role in inhibiting colon cancer cell growth. Our study investigated the role of dietary supplementation with microencapsulated probiotics (Bf and Lg) along with quercetin in the development of mouse colorectal cancer (CRC). Methods: Adenomatous polyposis coli/multiple intestinal neoplasia (ApcMin/+) mice were fed a standard diet or the same diet supplemented with microencapsulated probiotics (Bf and Lg strains, 107 CFU/100 g food) or both probiotics strains plus microencapsulated quercetin (15 mg/100 g food) for 73 days. Changes in body and organ weights, energy metabolism, intestinal microbiota, and colon tissue were determined. The expression of genes related to the Wnt pathway was also analyzed in colon samples. Results: Dietary supplementation with microencapsulated probiotics or microencapsulated probiotics plus quercetin reduced body weight loss and intestinal bleeding in ApcMin/+ mice. An improvement in energy expenditure was observed after 8 weeks but not after 10 weeks of treatment. A supplemented diet with microencapsulated Bf and Lg reduced the number of aberrant crypt foci (ACF) and adenomas by 45% and 60%, respectively, whereas the supplementation with Bf, Lg and quercetin decreased the number of ACF and adenomas by 57% and 80%, respectively. Microencapsulated Bf and Lg in combination with quercetin could exert inhibition of the canonical Wnt/β-catenin signaling pathway in the colon of ApcMin/+ mice Conclusions: The administration of microencapsulated Bf and Lg, individually or in combination with quercetin, inhibits the CRC development in ApcMin/+ mice.

Colon cancer incidence is increased in the occidental countries, prevention is very important to reduce the incidence of this disease. Functional foods could play a modulating function on colon cancer development. The aim of our study was to study the cellular and molecular effects of quercetin on the proliferation of human HT‐29 colon cells.HT‐29 cells were obtained from the European Collection of Cell Culture (EACC) and cultured in Dulbecco's modified Eagle's medium supplemented. At 80% confluence, cells were plated in 96‐well plates at 4x104cells/well and then were incubated in serum‐free medium in the presence or absence of various concentrations of quercetin (50µM‐ 125µM) during 72h. Cell proliferation was measured by MTT assay. â‐Catenin plays an important role in the Wnt signaling pathway. The expression of â‐catenin in cells treated was analysed by western blott.Quercetin inhibited the proliferation of HT‐29 cells, being the cells treated with quercetin presented a significant decrease (p<0.001) in growth cells compared with control group. â‐catenin expression in the cells treated with quercetin during 48h is lower compared with cells treated during 24h and control group. This data suggests that quercetin shown beneficial effects related to cell proliferation, showing an inhibitory effect.This work was supported by Spanish Education and Science Ministry (AGL2006‐10296).