Carotenoid encapsulation: study of the effect on antioxidant and anti-inflammatory activity on adipose tissue
Cucumis melo; Nanoparticles; Anti-inflammatory agents; Adiposity; Oxidative stress; Antioxidants.
Due to their antioxidant activity, carotenoids reduce oxidative stress and act on the inflammatory process. When nanoencapsulated, they can preserve and/or enhance the functional properties. The present study is divided into chapters that assess how encapsulation improved the antioxidant and anti-inflammatory activity. The first and second chapters refer to a systematic review (SR), the first refers to the RS protocol with a prospective international registry of systematic reviews (PROSPERO) under the number: CRD42020142065 and the second to SR, in which we sought to gather and systematize, based on the available scientific literature, in vitro, ex vivo, in vivo studies to evaluate the effect of different carotenoid encapsulation techniques on antioxidant activity. Articles were selected according to the PICOS strategy (population, interventions, control, results, and type of study), and searches were performed in PubMed, Embase, Virtual Health Library, Scopus, ScienceDirect, and Web of Science databases. The methodological quality assessment was performed using the OHAT (Office of Health Assessment and Translation) tool. A total of 1577 articles were selected, resulting in 20 eligible studies. The results showed that encapsulation promoted changes in the chemical structure of carotenoids and the emergence of new chemical interactions and increased the surface area, resulting in the preservation and improvement of the antioxidant activity. The third chapter referred to the experimental study. It aimed to evaluate the effect of nanoencapsulation of the crude extract rich in carotenoids obtained from Cantaloupe melon (Cucumis melo L. var cantalupensis) (CE) in Wistar rats with inflammation induced by the consumption of the diet of high glycemic index and high glycemic load (HGLI) on the systemic and adipose inflammatory response of these animals. The CE was characterized and quantified by spectrophotometric and chromatographic methods, and the CE nanoencapsulated in gelatin (EPG) was characterized by physical, chemical and incorporation efficiency methods. The in vivo experiment was carried out for 11 days with Wistar rats (n = 20) with diet-induced inflammation, subdivided into four groups: no treatment (HGLI diet + water), conventional treatment (HGLI diet + nutritionally adequate diet), test treatment 1 [HGLI and CE diet (12.5mg/kg)] and test treatment 2 [HGLI and EPG (50mg/kg)]. The different groups were investigated concerning food consumption, caloric intake, caloric efficiency, and weight. Plasma inflammatory cytokines (TNF-α, IL-6, and leptin) were measured, and visceral adipose tissue weights (retroperitoneal, epididymal, and perirenal), and histopathological and histomorphometric analysis were performed. The results showed that for the in vivo experiment, no changes were observed in food consumption, caloric intake and efficiency, and weight (p > 0.05), but animals treated with EPG showed significant improvement (p < 0.05) in concentrations of inflammatory cytokines (IL-6 and leptin). There was no difference between the weights of visceral adipose tissues (p > 0.05), but it was found that the most prominent focal area of multilocular adipocytes was observed for the group treated with EPG. Thus, the present study presents a relevant scientific contribution, considering that SR generated information regarding the effect of encapsulation on antioxidant activity and, in the preclinical research, on inflammation.