Efeitos dos polifenóis na saúde intestinal de modelos pré-clínicos com obesidade induzida por dieta: revisão sistemática

Abstract

Polyphenols can compose the tools for the treatment of obesity through antioxidant, anti-inflammatory and microbiota modulating actions, with effects that widely reach the body, including the intestine. In this way, the systematization of scientific data regarding the effects and mechanisms of action of polyphenols on intestinal health is important to direct obesity coping strategies. The aim of the study was to gather evidence on the impact of polyphenolic compounds on gut health in experimental models of diet-induced obesity. The development of the systematic review was outlined by the Preferred Reporting Items for Systematic Review and Metanalysis (PRISMA). Each step of the review was carried out independently by two researchers. Experimental studies in rats and mice with diet-induced obesity and treated with isolated polyphenols were included, retrieved through the formulation of search strategies applied in the following scientific study databases: PubMed, Science Direct, Scopus, Web of Science and EMBASE. The methodological quality of each selected study was evaluated using the Systematic Review Center for Laboratory Animal Experimentation (SYRCLE) tool by two independent evaluators. There was a high degree of agreement between the evaluators (Kappa coefficient > 0.85). It wasn’t possible to carry out the meta-analysis due to the heterogeneity of the studies in terms of methodology, presentation of results and lack of statistical data. Initially, 1415 publications were retrieved, after applying the eligibility criteria, 20 articles were inserted in the systematic review. Data related to intestinal health (modulation of the microbiota, and other parameters, such as production of short-chain fatty acids, analysis of tight junctions of the intestinal barrier, endotoxemia, morphology and histology and expression of intestinal tissue cytotoxins) were extracted. The SYRCLE assessment showed scores between 4.5 - 7.0 (maximum 10). Data analysis showed clear changes in the intestinal microbiota, such as an increase in alpha and beta diversities (46.7% and 68.8% of the studies that performed the analysis, respectively), reduction of the Firmicutes/Bacteroidetes (F:B) ratio (80% of the studies that performed the analysis, respectively). performed the analysis), and population changes at phylum, family and genera levels, through treatment with different phenolic compounds. There was also an increase in total SCFA production, greater expression of tight junctions, improvement in intestinal tissue morphology and histology, reduction in LPS (endotoxemia) and inflammatory cytokines. In all, 18 different polyphenols were evaluated in the studies. The phenolic compounds that showed positive effects were: curcumin, quercetin, chlorogenic acid, rutin, puerarin, epigallotequin-3-gallate, sinapic acid, vanillin, trilobatin, hydroxytyrosol, phlorizin and hydroxysaflor yellow A. Therefore, it is concluded that the administration of some polyphenols can help in the treatment of obesity by modulating the microbiota and improving other parameters related to intestinal health. It is not possible to extrapolate the conclusion to phenolic compounds in general, as the number of investigated compounds was limited, as well as evidence that structure, dose, treatment time and other factors affect the result. PROSPERO CRD42021262445.