RESUMEN
Diabetes mellitus is a metabolic disorder that affects millions of people worldwide and is linked to oxidative stress and inflammation. Thiazolidinediones (TZD) improve insulin sensitization and glucose homeostasis mediated by the activation of peroxisome proliferator-activated receptors γ (PPARγ) in patients with type 2 diabetes. However, their use is associated with severe adverse effects such as loss of bone mass, retention of body fluids, liver and heart problems, and increased risk of bladder cancer. Partial PPARγ agonists can promote the beneficial effects of thiazolidinediones with fewer adverse effects. Endophytic fungi colonize plant tissues and have a particularly active metabolism caused by the interaction with them, which leads to the production of natural products with significant biological effects that may be like that of the colonized plant. Here, we identify seven endophytic fungi isolated from Bauhinia variegata leaves that have antioxidant activities. Also, one of the extracts presented pan-agonist activity on PPAR, and another showed activity in PPARα and PPARß/δ. A better understanding of this relationship could help to comprehend the mechanism of action of antioxidants in treating diabetes and its complications. Moreover, compounds with these capabilities to reduce oxidative stress and activate the receptor that promotes glucose homeostasis are promising candidates in treatment of diabetes.
RESUMEN
Endophytes are considered an essential source of natural products. Skin is the body's largest organ; its primary function is the protection of other organs, and aging is one of the most relevant problems associated with this organ. UV radiation generates reactive oxygen species (ROS), which lead to skin degeneration and consequent aging. The main endogenous antioxidants that neutralize ROS are enzymatic antioxidants such as superoxide dismutase (SOD), catalase, glutathione peroxidase, and glutathione reductase, and non-enzymatic antioxidants, such as glutathione and α-tocopherol. Nuclear receptors are involved in molecular mechanisms that control the aging process, especially peroxisome proliferator-activated receptors (PPAR), which regulate the function and expression of genes that modulate the balance between matrix metalloproteinases (MMP) activity and the expression of collagen. Some natural compounds, such as polyphenols, can activate PPAR and reduce the activation of MMP and collagen degradation. In this work, the antioxidant activity of the mycelia methanolic extracts of two endophytic fungi isolated from leaves of Bauhinia variegata, named BvFV and BvFIX, their action as PPAR agonists, and their effect on the activity of antioxidant defense system enzymes were evaluated. The mycelia methanolic extract of BvFV showed a weak agonist effect on PPARß/δ, a high capability to inhibit lipid peroxidation, increased catalase activity, and increased superoxide dismutase activity by approximately 64%. In contrast, BvFIX increased catalase activity and increased superoxide dismutase activity in a dose-dependent manner, with an increase of 49.62% ± 7.87%, 56.64% ± 12.27%, and 240.46% ± 26.11% at concentrations of 25 µg/mL, 50 µg/mL and 100 µg/mL, respectively, in human dermal fibroblasts submitted to oxidative stress. These results suggest that the metabolites of the mycelia of endophytic fungi studied are promising to act in the chemoprevention of skin aging.
RESUMEN
Data about harms or benefits associated with the consumption of aspartame, a nonnutritive sweetener worldwide consumed, are still controversial. This systematic review and meta-analysis of randomized controlled clinical trials aimed to assess the effect of aspartame consumption on metabolic parameters related to diabetes and obesity. The search was performed on Cochrane, LILACS, PubMed, SCOPUS, Web of Science databases, and on a gray literature using Open Grey, Google Scholar, and ProQuest Dissertations & Theses Global. Searches across all databases were conducted from the earliest available date up to April 13, 2016, without date and language restrictions. Pooled mean differences were calculated using a random or fixed-effects model for heterogeneous and homogenous studies, respectively. Twenty-nine articles were included in qualitative synthesis and twelve, presenting numeric results, were used in meta-analysis. Fasting blood glucose (mmol/L), insulin levels (µU/mL), total cholesterol (mmol/L), triglycerides concentrations (mmol/L), high-density lipoprotein cholesterol (mmol/L), body weight (kg), and energy intake (MJ) were considered as the main outcomes in subjects that consumed aspartame, and results were presented as mean difference; % confidence interval, range. Aspartame consumption was not associated with alterations on blood glucose levels compared to control (-0.03 mmol/L; 95% CI, -0.21 to 0.14) or to sucrose (0.31 mmol/L; 95% CI, -0.05 to 0.67) and on insulin levels compared to control (0.13 µU/mL; 95% CI, -0.69 to 0.95) or to sucrose (2.54 µU/mL; 95% CI, -6.29 to 11.37). Total cholesterol was not affected by aspartame consumption compared to control (-0.02 mmol/L; 95% CI, -0.31 to 0.27) or to sucrose (-0.24 mmol/L; 95% CI, -0.89 to 0.42). Triglycerides concentrations were not affected by aspartame consumption compared to control (0.00 mmol/L; 95% CI, -0.04 to 0.05) or to sucrose (0.00 mmol/L; 95% CI, -0.09 to 0.09). High-density lipoprotein cholesterol serum levels were higher on aspartame compared to control (-0.03 mmol/L; 95% CI, -0.06 to -0.01) and lower on aspartame compared to sucrose (0.05 mmol/L; 95% CI, 0.02 to 0.09). Body weight did not change after aspartame consumption compared to control (5.00 kg; 95% CI, -1.56 to 11.56) or to sucrose (3.78 kg; 95% CI, -2.18 to 9.74). Energy intake was not altered by aspartame consumption compared to control (-0.49 MJ; 95% CI, -1.21 to 0.22) or to sucrose (-0.17 MJ; 95% CI, -2.03 to 1.69). Data concerning effects of aspartame on main metabolic variables associated to diabetes and obesity do not support a beneficial related to its consumption.