Polyphenol-Rich Foods for Human Health

In vitro study of potential prebiotic properties of monovarietal extra virgin olive oils

Olive oil, essential ingredient of the Mediterranean diet, is attracting a growing interest due to increasing evidence on its beneficial effects on human health. This study investigated whether extra virgin olive oil (EVOO) possess prebiotic properties. Twenty different monovarietal EVOO samples from 5 Marche region cultivars (Italy) were studied. The prebiotic activity of EVOOs was assessed monitoring the selective stimulation of gut bacterial species and the short chain fatty acids (SCFAs) production, using an in vitro fermentation system. All EVOOs selectively stimulated Lactobacillus spp., with a stronger activity than that observed in the inulin fermentation (positive control). Also, the bifidobacteria population increased; this bifidogenic stimulation was of EVOOs from Raggia cultivar. SCFAs appeared significantly higher after 24 h in all EVOO fermentations than in the control. Acetic and propionic acids production was particularly stimulated. Overall, most of the investigated EVOOs had a potential prebiotic activity, similar or stronger than inulin.

Oxidative Stress and Total Phenolics Concentration in COPD Patients-The Effect of Exercises: A Randomized Controlled Trial

Patients with chronic obstructive pulmonary disease (COPD) suffer from exercise intolerance, the sensation of dyspnea, and fatigue, which are the main reasons for limiting their physical activity. In addition to changes in the respiratory and circulatory systems in patients with COPD, peripheral muscle dysfunction, with numerous metabolic dysfunctions, is observed. One of the symptoms of the described anomalies, among others, is an antioxidative and prooxidative imbalance. The aim of the study was to demonstrate the impact of endurance training, carried out in the extended pulmonary rehabilitation program in COPD patients, on the imbalance between prooxidants and antioxidants in their bodies. Methods: The tests were carried out on a group of patients (n = 32) with COPD; 20 randomly selected people underwent a modified rehabilitation program during their rehabilitation stay, and the obtained results were compared with the results of 12 patients (control group) who were treated without endurance training. At the beginning and at the end of the study, spirometry and cardiopulmonary exercise tests (CPET) were performed. Oxidative stress (allantoin (All) and substances which react with thiobarbituric acid) and antioxidant (ferric reducing ability of plasma and total phenolics) parameters’ concentrations were determined in the venous blood. Results: In the study group, greater post-training increases of VO2max (p = 0.0702) and FEV1/FVC (p < 0.05; ES: 0.436) were reported. The applied CPET at each time caused an increase in the All concentration (p < 0.05) in the study and control groups. Conclusions: Endurance training applied as a part of the rehabilitation process did not cause the additional aggravation of oxidative stress and blood total phenolics concentration.

Optimization of Ultrasound-Assisted Extraction of Phloretin and Other Phenolic Compounds from Apple Tree Leaves (Malus domestica Borkh.) and Comparison of Different Cultivars from Estonia

Polyphenolic compounds, plant secondary metabolites essential for plant survival, are known for their high antioxidant and anti-inflammatory activity. In addition, several polyphenols, such as phloretin, also have potential antiviral effects, making these compounds potential ingredients of biofunctional foods. A promising source for the extraction of phloretin is a by-product of apple production—apple tree leaves. Focusing on green technologies, the first aim of the present study was to optimize the direct ultrasound-assisted extraction conditions to gain the maximum yield of phloretin from air-dried apple leaves. For the optimization of process parameters, we applied the response surface method with Box–Behnken design. The optimal extraction conditions were extraction time 14.4 min, sonication amplitude 10% and 10 g of sample per 100 mL solvent (70% ethanol, w/w). Using these conditions, we assessed the content of individual and total polyphenolic compounds along with antioxidant activity in the leaves of different autumn and winter apple cultivars grown in Estonia. The analyses were carried out with chromatographic (HPLC-DAD-MS/MS) and spectrophotometric methods. The phloretin concentration ranged from 292 to 726 µg/g and antioxidant activity from 6.06 to 11.42 mg GA eq./g, these being the highest in the local winter cultivars ‘Paide taliõun’ and ‘Tellissaare’, respectively.