The role of oxidaTive sTress on The paThophysiology of meTabolic syndrome rev assoc Med Bras 2017; 63(1):85-91 85 REVIEW ARTICLEThe role of oxidative stress on the pathophysiology of metabolic syndrome Metabolic syndrome (MetS) has a high prevalence around the world. Considering the components used to classify MetS, it is clear that it is closely related to obesity. These two conditions begin with an increase in abdominal adipose tissue, which is metabolically more active, containing a greater amount of resident macrophages compared to other fat deposits. Abdominal adiposity promotes inflammation and oxidative stress, which are precursors of various complications involving MetS components, namely insulin resistance, hypertension and hyperlipidemia. One way to block the effects of oxidative stress would be through the antioxidant defense system, which offsets the excess free radicals. It is known that individuals with metabolic syndrome and obesity have high consumption of fats and sugars originated from processed foods containing high levels of sodium as well as low intake of fruits and vegetables, thus maintaining a state of oxidative stress, that can speed up the onset of MetS. Healthy eating habits could prevent or delay MetS by adding antioxidant-rich foods into the diet.

The effects of hydroethanolic extract of Yacon leaves (HEYL) on antioxidant, glycemic, and inflammatory biomarkers were tested in diabetic rats. Outcome parameters included glucose, insulin, interleukin-6 (IL-6), and hydrophilic antioxidant capacity (HAC) in serum and IL-6, HAC, malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) in soleus. The rats (10/group) were divided as follows: C, controls; C + Y, HEYL treated; DM, diabetic controls; and DM + Y, diabetic rats treated with HEYL. Diabetes mellitus was induced by administration of streptozotocin. C + Y and DM + Y groups received 100 mg/kg HEYL daily via gavage for 30 d. Hyperglycemia was improved in the DM + Y versus DM group. Insulin was reduced in DM versus C group. DM rats had higher IL-6 and MDA and lower HAC in the soleus muscle. HEYL treatment decreased IL-6 and MDA and increased HAC in DM rats. DM + Y rats had the highest CAT activity versus the other groups; GPx was higher in C + Y and DM + Y versus their respective controls. The apparent benefit of HEYL may be mediated via improving glucoregulation and ameliorating oxidative stress and inflammation, particularly in diabetic rats.

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Obesity is considered an important risk factor for several disorders, such as diabetes mellitus, systemic arterial hypertension, dyslipidemia, and atherosclerosis, which are associated with inflammation and oxidative stress as a trigger factor. Passiflora edulis contains important bioactive compounds, such as phenolics, carotenoids, vitamin C, and polyamines in pulp, leaves, seeds, and bark. Aim: To evaluate the effect of bark of Passiflora edulis (BPe) on body composition, and metabolic and oxidative stress parameters in genetically obese mice. Methods: Obese male db/db mice (n = 14 animals) received normal feeds and water ad libitum for 8 weeks. Then, animals were randomly divided to continue either receiving standard chow (obese, n = 7 (OB)) or feed with standard chow plus bark Passiflora edulis (BPe) (obese + BPe, n = 7 (OB + BPe)) for 8 more weeks, totaling 16 weeks. BPe was added to chow (7 g of BPe/kg of chow corresponding to 1.5 g/kg of body weight). The parameters evaluated in animals included food and caloric intake, body weight, body fat, plasma glucose, triglycerides, and total cholesterol. Malondialdehyde and antioxidant capacity were evaluated in plasma and organs. Groups were compared by Student t-test, with p < 0.05. Results: BPe reduced visceral and subcutaneous fat deposit and adiposity index, cholesterol and triglyceride levels, ameliorated the antioxidant capacity, and reduced malondialdehyde (MDA) levels. Conclusion: the bark of Passiflora edulis was effective in improving body composition, and metabolic and antioxidant parameters in obese mice.