M.T. Fernández-Ponce

Green Extraction of Antioxidants from Different Varieties of Red Grape Pomace

The extraction yield, phenolic content, anthocyanin content and antioxidant activity of extracts from different varieties of red grapes, Cabernet Sauvignon, Merlot, Petit Verdot, Syrah, Tempranillo and Tintilla, using pressurized green solvents have been analyzed. Two techniques were studied and compared: supercritical fluid extraction (SFE) with CO2 + 20% ethanol and pressurized liquid extraction (PLE) with either ethanol, water or an ethanol/water mixture as the extraction solvents. The Petit Verdot variety allowed the highest global and phenolic yield, and antioxidant activity. The best conditios for PLE obtained from the experimental design and kinetic study were 50% ethanol/water as the pressurized solvent at 90 bar, 120 °C, a flow rate of 5 g/min and, an extraction time of 90 min. A statistical analysis of variance has been performed and it was found that temperature is the only variable that has a statistical influence on the extraction yield. The antioxidant activity levels of the extracts are very promising and they are similar to those obtained with the antioxidant tocopherol.

Mango leaf extract improves central pathology and cognitive impairment in a type 2 diabetes mouse model.

Epidemiological studies reveal that metabolic disorders, and specifically type 2 diabetes (T2D), are relevant risk factors to develop Alzheimers disease (AD) and vascular dementia (VaD), the most common causes of dementia. AD patients are in a tremendous need of new therapeutic options because of the limited success of available treatments. Natural polyphenols, and concretely Mangifera indica Linn extract (MGF), have been reported to have antiinflammatory, antioxidant and antidiabetic activities. The role of MGF in central complications associated with T2D, after long‐term treatment of db/db mice with MGF was analyzed. Metabolic parameters (body weight, glucose and insulin levels) as well as central complications including brain atrophy, inflammatory processes, spontaneous bleeding, tau phosphorylation and cognitive function in db/db mice treated with MGF for 22 weeks were assessed. MGF limits body weight gain in obese db/db mice. Insulin and C‐peptide levels, indicative of pancreatic function, were longer maintained in MGF‐treated animals. MGF reduced central inflammation by lowering microglia burden, both in the cortex and the hippocampus. Likewise, central spontaneous bleeding was significantly reduced in db/db mice. Cortical and hippocampal atrophy was reduced in db/db mice and tau hyperphosphorylation was lower after MGF treatment, resulting in partial recovery of learning and memory disabilities. Altogether, the data suggested that MGF treatment may provide a useful tool to target different aspects of AD and VaD pathology, and could lead to more effective clinical therapies for the prevention of metabolic related central complications associated with AD and VaD.

Preparation of polyphenol fine particles potent antioxidants by a supercritical antisolvent process using different extracts of Olea europaea leaves

Various extracts from olive leaves have been precipitated by a supercritical antisolvent (SAS) process to evaluate the possibility of producing polyphenol fine particles with controlled size and size distribution. Olive leaves were initially extracted with subcritical fluids using mixtures of CO2+ethanol at 10% and 50%, by pressurized liquid extraction (PLE) with water, ethanol and a hydroalcoholic mixture (50: 50) (v/v), and also by conventional ethanol extraction (CE). PLE gave the extract with the highest yield and the best antioxidant activity. SAS precipitation was unsuccessful for the extracts obtained with pressurized water and with the hydroalcoholic mixture (50: 50) (v/v). The SAS precipitates with the smallest particle sizes were produced from extracts obtained with subcritical fluids. The SAS precipitates obtained after the conventional ethanol extraction of olive leaves showed the best antioxidant activity.