Extratos de Hylocereus Lemairei (Hook.)Britton & Rose : composição química, atividade antioxidante e efeitos biológicos em modelo de hiperglicemia in vitro

Abstract

Red-fleshed Pitaya (Hylocereus lemairei (Hook.) Britton & Rose) is an exotic fruit that is increasingly attracting the scientific community's attention due to its antioxidant and antiinflammatory action. Antioxidants contribute to maintaining the balance between the production of Reactive Oxygen Species (ROS) and cellular defense capacity, preventing oxidative stress, which is associated with several diseases, including Diabetes Mellitus (DM). DM is an inflammatory and chronic disease and it is known that, even in medicated patients, oxidative stress persists and could collaborate for disease progression (comorbidities). This study aimed to produce and characterize peel and pulp extracts of red pitaya (H. lemairei) and to investigate their biological effects on intestinal (CACO-2) and endothelial (EA.hy926) cells exposed to high glucose concentration (35mM). Extracts capacity from inhibiting enzymes involved in carbohydrate metabolism (α-amylase and α-glycosidase) and lipids (pancreatic lipase) were also evaluated. The results were compared to Ascarbose and Orlistat, respectively. Metformin, the main drug used in the pharmacological treatment of DM type 2 (DM2), was used for comparison. Both extracts showed antioxidant activity superior to vitamin C and chlorogenic acid, two recognized antioxidants. The antioxidant activity of pitaya peel extract was about two times higher than pulp. Both exhibited significant anthocyanin and phenolic content, chlorogenic acid (12,705mg/100g for the peel and 8,352 mg/100g for the pulp) and naringin flavonoid (12,010 mg/100g for the peel and 7,177 mg/100g for the pulp) the most abundant. Hesperidin, ferulic acid, and catechins were found only in peel extract. Extracts exhibited a better performancec against α-glucosidase enzyme inhibition (> 60% inhibition) when compared to Ascarbose, in addition to a similar inhibition to the Orlistat against lipase pancreatic activity (>90% inhibition), indicating an action directed to the gut. It was observed a slight inhibition of α-amylase activity (< 10% inhibition) by the extracts. Both were effective in attenuating oxidative stress (ROS levels), inflammation (ON), and viability reducing (MTT) caused by hyperglycemia, both in enterocytes and endothelial cells. Specifically, in endothelial cells, it was observed alterations in the mitochondrial membrane potential (ΔΨm), intracellular pH (pHi), apoptosis, and mitochondrial activity (CI, CII, and ATP synthase), as well as increased levels of lactate and lipoperoxidation. At the same time, COX-2, Nfk-β, and NLRP3 expression levels were increased in the hyperglycemic group. In addition, antioxidant enzymes (SOD and CAT) and sulfhydryl protein content were depleted. Both extracts were able to reverse these changes, however, their effects when compared to metformin per se and when used in combination, were more expressive. Data from a principal component analysis (PCA) indicate that peel extract showed a better effect against oxidative-inflammatory alterations caused by endothelium hyperglycemia. These findings will contribute to the development of new supporting therapeutic approaches in the treatment of DM2 and complications. [resumo fornecido pelo autor]