Preventive effects of freeze-dried jaboticaba peel on experimental colorectal cancer model: clinical and histophysiopathological evaluation

• Grant number: 20/00414-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): August 01, 2020
• Effective date (End): December 31, 2021
• Field of knowledge: Agronomical Sciences - Food Science and Technology - Food Science
• Principal Investigator: Mário Roberto Maróstica Junior
• Grantee: Julia Soto Rizzato
• Host Institution: Faculdade de Engenharia de Alimentos (FEA). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

Incidence and mortality of colorectal cancer (CRC) has been growing since 1950. In the last century, CRC was considered a rare disease, but nowadays it's the second most common type of cancer and the third one in mortality. Initially, this type of cancer had an incidence much higher in developed countries in comparison with the ones in development. However, in the last decade, Latin American countries, such as Brazil, had a significant expansion in the number of cases, reaching the incidence of European countries, such as Switzerland and France. This shows the importance and need of new research with a preventive aspect, aiming to control the global burden of CRC. Around 75% of CRC cases are sporadic, pointing that the disease development suffers most influence from environmental factors, even though it is still a problem related to genetic factors. A diet rich in fruits with a high content in fibers and phenolic compounds may reduce significantly the chances of developing CRC. Jaboticaba is a native Brazilian fruit rich in bioactive compounds, such as fibers and phenolic compounds. The fibers are especially abundant in the seeds and peel of jaboticaba and its consumption is inversely related to the development of CRC, due to the ability of fibers to dilute fecal carcinogens, lowering the time in which feces are in colon and also, because they generate short-chain fatty acids by fermentation from microbiota. Phenolic compounds, on the other hand, are in its majority on the peel. Anthocyanins are the most abundant phenolic compounds that can be found in jaboticaba peel and may present antioxidant, anti-inflammatory and anti-cancer properties, since they are capable of suppressing the expression of pro-inflammatory agents, such as Beta-catenin, factor nuclear kappa B (NF-kB) and signal transducer and activator of transcription 3 (STAT3). Having this in mind, this project aims to investigate the effects of jaboticaba peel on clinical activity, incidence and size of tumors, as well as protein's expression/concentration in a model of inflammation-driven CRC. In order to achieve that, mice will be given freeze-dried jaboticaba's peel through the AIN-93M diet in concentrations of 0 or 2.5%. After 14 days, CRC will be induced through an intraperitoneal injection of azoxymethan (10 mg/kg) and seven days later, 2% dextran sodium sulfate solution will be added to the drinking water for one week. Disease Activity Index (body weight, rectal bleeding and stool consistency) will be evaluated during the experiment. On day 100, mice will be euthanized, and colon samples will be taken for histological analysis, immunohistochemistry, enzyme-linked immunosorbent assay (ELISA) and real time polymerase chain reaction (qPCR). Histology slides will be analyzed in a blind way. Adenoma and carcinoma's incidence, multiplicity, size and depth will be assess. For immunohistochemistry, the expression of the following proteins will be analysed: Beta-catenin, Adenomatous Polyposis Coli (APC), Cyclo-oxygenase 2 (COX-2), inducible nitric oxide synthase (iNOS), NF-kB and STAT3. By ELISA, the concentration of Tumor Necrosis Factor Alpha (TNF-alpha), Interleukin 1Beta (IL-1BETA) and Interleukin 6 (IL-6) will be determined. Finally, by qPCR, the expression of Beta-catenin and APC will be determined. From the execution of this project, it is expected that jaboticaba peel will be capable of reducing the incidence and multiplicity of carcinomas or eliminating the induced CRC, revealing its efficacy for disease's prevention.