Aging is defined as the functional loss of tissues and organs over time. This is a biological, irreversible, progressive, and universal process that results from genetic and environmental factors, such as diet, physical activity, smoking, harmful alcohol consumption, and exposure to toxins, among others. Aging is a consequence of molecular and cellular damage built up over time. This damage begins with a gradual decrease in physical and mental capacity, thus increasing the risk of neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease. Neuronal, functional, and structural damage can be explained by an imbalance among free radicals, reactive oxygen species, reactive nitrogen species, and antioxidants, which finally lead to oxidative stress. Due to the key role of free radicals, reactive oxygen species, and reactive nitrogen species, antioxidant therapy may reduce the oxidative damage associated with neurodegeneration. Exogenous antioxidants are molecules that may help maintain the balance between the formation and elimination of free radicals, thus protecting the cell from their toxicity. Among them, polyphenols are a broad group of secondary plant metabolites with potent antioxidant properties. Here, we review several studies that show the potential role of polyphenol consumption to prevent, or slow down, harmful oxidative processes linked to neurodegenerative disorders.

The consumption of dietary fiber (DF) has been associated with a reduced incidence of non-communicable diseases. Despite various strategies implemented worldwide to increase DF intake, it remains low. Therefore, the development of new fiber-rich food products that are widely consumed could be a strategy to improve DF intake. In this study, an agro-industrial by-product, pomegranate peel powder (PPP), was used as an innovative source of DF and antioxidant. The objective was to develop a bread enriched with DF, antioxidants, and sensory characteristics by partially replacing wheat flour (WF) with PPP at levels of 0%, 2.5%, 5%, 7.5%, and 10%. Bread with 2.5% and 5% PPP was chosen for a clinical trial to evaluate glycemic response (GR) in healthy subjects and determine the bread’s glycemic index (GI). As the percentage of PPP increased, both the DF and total polyphenol content increased significantly. The highest overall acceptability was achieved with bread containing up to 5% PPP. Consumption of bread with 2.5% and 5.0% PPP significantly reduced the GI compared to the control bread, while the decrease in GR was not significant. PPP could be a potential food and low-cost ingredient to improve the bread’s nutritional quality through its contribution to DF and antioxidants.

Phenolic compounds have recently gained interest, as they have been related to improvements in health and disease prevention, such as inflammatory intestinal pathologies and obesity. However, their bioactivity may be limited by their instability or low concentration in food matrices and along the gastrointestinal tract once consumed. This has led to the study of technological processing with the aim of optimizing phenolic compounds’ biological properties. In this sense, different extraction systems have been applied to vegetable sources for the purpose of obtaining enriched phenolic extracts such as PLE, MAE, SFE, and UAE. In addition, many in vitro and in vivo studies evaluating the potential mechanisms of these compounds have also been published. This review includes a case study of the Hibiscus genera as an interesting source of phenolic compounds. The main goal of this work is to describe: (a) phenolic compound extraction by designs of experiments (DoEs) applied to conventional and advanced systems; (b) the influence of the extraction system on the phenolic composition and, consequently, on the bioactive properties of these extracts; and (c) bioaccessibility and bioactivity evaluation of Hibiscus phenolic extracts. The results have pointed out that the most used DoEs were based on response surface methodologies (RSM), mainly the Box–Behnken design (BBD) and central composite design (CCD). The chemical composition of the optimized enriched extracts showed an abundance of flavonoids, as well as anthocyanins and phenolic acids. In vitro and in vivo studies have highlighted their potent bioactivity, with particular emphasis on obesity and related disorders. This scientific evidence establishes the Hibiscus genera as an interesting source of phytochemicals with demonstrated bioactive potential for the development of functional foods. Nevertheless, future investigations are needed to evaluate the recovery of the phenolic compounds of the Hibiscus genera with remarkable bioaccessibility and bioactivity.

This study focused on the oil extraction from freeze-dried maqui (Aristotelia chilensis) by supercritical fluid extraction with carbon dioxide (SFE-CO₂). The basic objective was to optimize the oil yield and the tocopherol concentration. A Box/Behnken experimental design was developed with three processing variables: supercritical pressure (74, 187, and 300 bar), temperature (35, 48, and 60 °C), and extracting time (30, 135, and 240 min). Multiple optimizations, based on the combination of factor levels at 274 bar, 240 min, and 60 °C, led to the highest oil yield and tocopherol values. The validation of the optimized conditions of maqui oil extraction led to an oil yield of 8% and values of 735, 53, and 97 (mg·kg⁻¹ oil) for α-tocopherol, α-tocotrienol, and γ-tocopherol, respectively. A higher concentration of tocopherol compounds was observed when compared to the employment of the conventional extracting method. The optimized SFE-CO₂ method led to an oil extract exhibiting higher Hydrophilic-Oxygen Radical Absorbance Capacity (H-ORAC) assay and total phenol content (22 μmol Trolox equivalents·g⁻¹ oil and 28 mg gallic acid equivalents·g⁻¹ oil) than the oil obtained by the conventional procedure. A practical and accurate oil extraction is proposed for obtaining tocopherol-enriched oil including high concentrations of valuable lipophilic antioxidants.

Olive oil, a cornerstone of the Mediterranean diet, contains trace amounts of oleuropein, a polyphenolic compound and its active metabolite hydroxytyrosol, which exhibit significant neuroprotective effects by reducing oxidative stress and brain inflammation. These properties make them promising for managing neurodegenerative diseases such as Alzheimer’s disease. This review synthesizes the current literature on the chemistry, biosynthesis, and neuroprotective activities of oleuropein and hydroxytyrosol, emphasizing their antioxidant and anti-inflammatory effects. Research indicates that hydroxytyrosol is bioavailable and rapidly distributed throughout the body, including brain tissue, due to its ability to cross the blood-brain barrier. In contrast, oleuropein requires metabolic conversion for bioavailability. Both compounds have been shown in preclinical animal studies to mitigate oxidative stress, promote autophagy, and facilitate the clearance of amyloid-beta aggregates. Moreover, they have been found to alleviate mitochondrial damage and dysfunction, which are critical factors in neurodegeneration. In animal and human studies, oleuropein and hydroxytyrosol have improved cognitive function, reduced neuroinflammation, and improved overall brain health. The mechanisms underlying these effects include the restoration of redox balance and the modulation of inflammatory pathways in the aging brain. Despite these promising findings, human clinical trials are needed to assess the long-term safety and efficacy of oleuropein and hydroxytyrosol in clinical settings. Understanding their role in neuroprotection could lead to effective interventions for preventing or slowing cognitive decline associated with aging and neurodegenerative diseases. Overall, oleuropein and hydroxytyrosol represent a compelling area of study within the realm of antioxidants and their application in neuroprotection.

This study evaluated the effects of cold-pressed maqui (Aristotelia chilensis (Mol.) Stuntz) seed oil (MO) on liver metabolism and biochemical markers in a high-fat diet (HFD) murine model. In it, the fatty acid profile, tocopherol and tocotrienol contents, and antioxidant capacity of MO were analyzed. Male C57BL/6 mice were divided into four groups (i.e., a, b, c, and d groups) and supplemented for 12 weeks according to the following distribution: (a) control diet (CD)-sunflower oil (SO), (b) CD+MO, (c) HFD+SO, and (d) HFD+MO. Total body and organ weights, serum markers, and liver fat infiltration were assessed. MO contained 32.31% oleic acid, 46.41% linoleic acid, and 10.83% α-linolenic acid; additionally, α- and γ-tocopherol levels were 339.09 ± 5.15 and 135.52 ± 38.03 mg/kg, respectively, while β-, δ-tocopherol, and α-tocotrienol were present in trace amounts and the antioxidant capacity measured was 6.66 ± 0.19 μmol Trolox equivalent/g. MO supplementation significantly reduced the visceral fat (0.76 ± 0.06 g vs. 1.32 ± 0.04 g) and GPT (glutamate pyruvate transaminase) levels (71.8 ± 5.0 vs. 35.2 ± 2.6 U/L), and the liver fat infiltration score (6 vs. 3) in the HFD+MO group compared to HFD+SO. It is suggested that MO may effectively prevent fatty liver disease, warranting further research on its potential benefits for human health.