Metformin can act in muscle, inhibiting the complex I of the electron transport chain and decreasing mitochondrial reactive oxygen species. Our hypothesis is that the inhibition of complex I can minimize damage oxidative in muscles of hypoinsulinemic rats. The present study investigated the effects of insulin and/or metformin treatment on oxidative stress levels in the gastrocnemius muscle of diabetic rats. Rats were rendered diabetic (D) with an injection of streptozotocin and were submitted to treatment with insulin (D+I), metformin (D+M), or insulin plus metformin (D+I+M) for 7 days. The body weight, glycemic control, and insulin resistance were evaluated. Then, oxidative stress levels, glutathione antioxidant defense system, and antioxidant status were analyzed in the gastrocnemius muscle of hypoinsulinemic rats. The body weight decreased in D+M compared to ND rats. D+I and D+I+M rats decreased the glycemia and D+I+M rats increased the insulin sensitivity compared to D rats. D+I+M reduced the oxidative stress levels and the activity of catalase and superoxide dismutase in skeletal muscle when compared to D+I rats. In conclusion, our results reveal that dual therapy with metformin and insulin promotes more benefits to oxidative stress control in muscle of hypoinsulinemic rats than insulinotherapy alone.

The increase in antioxidant responses promoted by regular physical activity is strongly associated with the attenuation of chronic oxidative stress and physiological mechanisms related to exercise adaptation. The aim of this work was to evaluate and compare how different exercise protocols (HIIE: high-intensity interval exercise, CE: continuous exercise, and RE: resistance exercise) may alter salivary and plasmatic antioxidants and salivary markers of exercise intensity and nitric oxide. Thirteen healthy, trained male subjects were submitted to the three exercise protocols. Blood and saliva samples were collected at the points preexercise, postexercise, and 3 hours postexercise. Antioxidants (total antioxidant capacity, superoxide dismutase and catalase activities, and levels of reduced glutathione and uric acid), markers of exercise intensity (salivary total protein and amylase activity), and salivary nitric oxide were evaluated. As a result, all exercise protocols increased the markers of exercise intensity and nitric oxide. Antioxidant response was increased after exercise, and it was found that a single HIIE session exerts a similar pattern of antioxidant response compared to CE, in plasma and saliva samples, while RE presented minor alterations. We suggest that HIIE may lead to alterations in antioxidants and consequently to the physiological processes related to redox, similar to the CE, with the advantage of being performed in a shorter time. In addition, the antioxidant profile of saliva samples showed to be very similar to that of plasma, suggesting that saliva may be an alternative and noninvasive tool in sports medicine for the study of antioxidants in different physical exercise protocols.

A polyphenol-enriched fraction from Annona crassiflora fruit peel (Ac-Pef) containing chlorogenic acid, (epi)catechin, procyanidin B2, and caffeoyl-glucoside was investigated against hepatic oxidative and nitrosative stress in streptozotocin-induced diabetic rats. Serum biochemical parameters, hepatic oxidative and nitrosative status, glutathione defense system analysis, and in silico assessment of absorption, distribution, metabolism, excretion, and toxicity (ADMET) of the main compounds of Ac-Pef were carried out. Ac-Pef treatment during 30 days decreased serum alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase activities, as well as hepatic lipid peroxidation, protein carbonylation and nitration, inducible nitric oxide synthase level, and activities and expressions of glutathione peroxidase, superoxide dismutase, and catalase. There were increases in antioxidant capacity, glutathione reductase activity, and reduced glutathione level. ADMET predictions of Ac-Pef compounds showed favorable absorption and distribution, with no hepatotoxicity. A. crassiflora fruit peel showed hepatoprotective properties, indicating a promising natural source of bioactive molecules for prevention and therapy of diabetes complications.

Restraint and cold stress induces the hypothalamic-pituitary-adrenal (HPA) axis to release corticosterone from the adrenal gland, which can worsen the antioxidant defense system in the central nervous system. Here, we investigated the corticosterone levels and the antioxidant defense system in the cerebellum and brain, as well as in its isolated regions, such as cerebral cortex, striatum and hippocampus of stressed rats supplemented with royal jelly (RJ). Wistar rats were supplemented with RJ for 14days and the stress induction started on the 7th day. Stressed rats increased corticosterone levels, glycemia and lipid peroxidation in the brain and cerebellum, cerebral cortex and hippocampus besides reduced glutathione defense system in the brain and striatum. Rats supplemented with RJ decreased corticosterone, maintained glycemia and decreased lipid peroxidation in the brain, cerebellum, as well as striatum and hippocampus, besides improved glutathione defense system in cerebral cortex and striatum. This study suggests an anti-stress and neuroprotective effect of RJ under stress conditions.

Objective: To verify if acute intake of beetroot juice potentiates post-exercise hypotension (PEH) in hypertensive postmenopausal women. Methods: Thirteen hypertensive postmenopausal women (58.1 ± 4.62 years and 27.4 ± 4.25 kg/m²) were recruited to participate in three experimental sessions, taking three different beverages: Beetroot juice (BJ), placebo nitrate-depleted BJ (PLA), and orange flavored non-caloric drink (OFD). The participants performed moderate aerobic exercise training on a treadmill, at 65–70% of heart rate reserve (HRR), for 40 min. After an overnight fast, the protocol started at 07h when the first resting blood pressure (BP) was measured. The beverage was ingested at 07h30 and BP was monitored until the exercise training started, at 09h30. After the end of the exercise session, BP was measured every 15 min over a 90-min period. Saliva samples were collected at rest, immediately before and after exercise, and 90 min after exercise for nitrite (NO2−) analysis. Results: There was an increase in salivary NO2− with BJ intake when compared to OFD and PLA. A slight increase in salivary NO2− was observed with PLA when compared to OFD (p < 0.05), however, PLA resulted in lower salivary NO2− when compared to BJ (p < 0.001). There were no changes in salivary NO2− with the OFD. Systolic and diastolic BP decreased (p < 0.001) on all post exercise time points after all interventions, with no difference between the three beverages. Conclusion: Acute BJ intake does not change PEH responses in hypertensive postmenopausal women, even though there is an increase in salivary NO2−.

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Restraint and cold stress increase both corticosterone and glycemia, which lead to oxidative damages in hepatic tissue. This study assessed the effect of royal jelly (RJ) supplementation on the corticosterone level, glycemia, plasma enzymes and hepatic antioxidant system in restraint and cold stressed rats. Wistar rats were allocated into no-stress, stress, no-stress supplemented with RJ and stress supplemented with RJ groups. Initially, RJ (200mg/Kg) was administered for fourteen days and stressed groups were submitted to chronic stress from the seventh day. The results showed that RJ supplementation decreases corticosterone levels and improves glycemia control after stress induction. RJ supplementation also decreased the body weight, AST, ALP and GGT. Moreover, RJ improved total antioxidant capacity, SOD activity and reduced GSH, GR and lipoperoxidation in the liver. Thus, RJ supplementation reestablished the corticosterone levels and the hepatic antioxidant system in stressed rats, indicating an adaptogenic and hepatoprotective potential of RJ.

This study tested the effect of isoflavone supplementation in addition to combined exercise training in salivary oxidative stress markers in non obese postmenopausal women. Thirty two post menopausal women without hormone therapy were randomly assigned to exercise + placebo (n = 15) or exercise + isoflavone supplementation (n = 17) groups. They performed 30 sessions of combined exercises (aerobic plus resistance) over ten weeks and consumed 100 mg of isoflavone supplementation or placebo. Saliva samples were collected after an overnight fast. Superoxide dismutase, total antioxidant capacity, thiobarbituric acid reactive substances, catalase, total protein and nitrite were determined before and after ten weeks of the intervention. The ANOVA two way analysis of variance was applied with α of 5%. Both groups increase (p<0.05) superoxide dismutase activity and decrease catalase levels. There was interaction (time × group) in both nitrite and thiobarbituric acid reactive substances results, with increase (p<0.05) in placebo group and decrease (p<0.05) in isoflavone group. No difference was found for total antioxidant capacity or total protein. The combination of isoflavone supplementation and exercise training can promote an antioxidant effect through reduction of lipid peroxidation and concentrations of salivary nitrite.