Cúrcuma e doença inflamatória intestinal : uma revisão sistemática de estudos em modelos animais e humanos e uma metanálise de estudos randomizados

Abstract

Inflammatory bowel disease (IBD) is a chronic inflammatory manifestation characterized by episodes of attenuation and aggravation of symptoms. It comprises Crohn's disease (CD) and idiopathic ulcerative colitis (UC). It has a multifactorial character, with contribution of environmental factors, intestinal microbiota, individual genetic susceptibility, immunological and psychological factors, with emphasis on the role of inflammation and oxidative stress in its emergence. Drug treatment, used for a prolonged time by patients, may occur with the appearance of adverse effects, dependence and/or refractory effect. Studies have pointed out that compounds with antioxidant effect can be considered a complementary alternative treatment for IBD. In this context, Curcuma longa, a perennial shrub whose rhizome presents in its chemical composition, among other substances, polyphenols called curcuminoids, being curcumin, the one with the highest biological activity. This liposoluble polyphenol has antioxidant action and interacts with various gene transcription factors, enzymes, inflammatory cytokines, proteins, growth factors and receptors, and additionally, does not present toxicity when tested between the range of 500 mg/day to 6 g/day, as indicated by human studies. Aiming to contribute to the analysis of the efficacy of oral use of Curcuma longa and its curcuminoids in IBD, this dissertation initially presents a literature review, which describes the characteristics of IBD, the complementary conventional and alternative treatments, the characterization of antioxidant and anti-inflammatory activity of Curcuma longa compounds and the mechanisms of action in IBD. The original article is a systematic review with meta-analysis, whose objective was to identify the effects of Curcuma longa, curcumin or other curcuminoids on metabolic symptoms and alterations in patients and animal models of IBD. For this review, a search was carried out in the databases PubMed, Science Direct, LILACS, CENTRAL e Clinical Trials until January 2021. The following keywords were used:"inflammatory bowel disease", “ulcerative colitis", "colitis", "Crohn disease", "curcumin”, "curcuma", "turmeric" e "indian saffron". Articles with experimental models of colitis and randomized clinical trials (RCT) were eligible. The primary outcome was the clinical remission and the secondary one, the endoscopic remission. Of the 997 records found, 62 articles were included, 54 with animal models and 8 RCT, of which 5 were included in the meta-analysis. Fifty studies (92.59%) in animals, allow to observe the improvement in macroscopic, histological and/or functional activity and 81.48% (n = 44) identified a decrease in oxidative and/or inflammatory levels of biomarkers in animals treated with curcumin. Among the RCT, the analysis of intent to treat showed that oral curcumin, associated with traditional pharmacological treatment, was effective in inducing clinical remission (n=281, RR: 3,15 CI 95% [1,22 - 8,10] p = 0,0017; I² = 72,2%, p = 0,006) and clinical response (n=259, RR: 1,60 CI 95% [1,09 - 2,35] p = 0,0017; I² = 59,7%, p = 0,042); but not in endoscopic remission (n= 161, RR: 2,91 CI 95% [0,58 – 14,58] p = 0,195; I² = 72,7%, p = 0,026). The results confirm that the oral prescription of Curcuma longa or curcumin, when associated with drug therapy, is effective in the treatment of patients with IBD.