Absolute Antioxidant Activity of Five Phenol-Rich Essential Oils

Bridging the Gap: Harnessing Plant Bioactive Molecules to Target Gut Microbiome Dysfunctions in Amyotrophic Lateral Sclerosis

The correlation between neurodegenerative diseases and the gut microbiome is increasingly evident, with amyotrophic lateral sclerosis (ALS) being particularly notable for its severity and lack of therapeutic options. The gut microbiota, implicated in the pathogenesis and development of ALS, plays a crucial role in the disease. Bioactive plant molecules, specifically volatile compounds in essential oils, offer a promising therapeutic avenue due to their anti-inflammatory properties and gut-modulating effects. Our narrative review aimed to identify microbiota-associated bacteria in ALS and analyze the benefits of administering bioactive plant molecules as much-needed therapeutic options in the management of this disease. A comprehensive search of PubMed database articles published before December 2023, encompassing research on cell, human, and animal ALS models, was conducted. After selecting, analyzing, and discussing key articles, bacteria linked to ALS pathogenesis and physiopathology were identified. Notably, positively highlighted bacteria included Akkermansia muciniphila (Verrucomicrobia phylum), Faecalibacterium prausnitzii, and Butyrivibrio spp. (Firmicutes phylum). Conversely, members of the Escherichia coli spp. (Proteobacteria phylum) and Ruminococcus spp. (Firmicutes phylum) stood out negatively in respect to ALS development. These bacteria were associated with molecular changes linked to ALS pathogenesis and evolution. Bioactive plant molecules can be directly associated with improvements in the microbiome, due to their role in reducing inflammation and oxidative stress, emerging as one of the most promising natural agents for enriching present-day ALS treatments.

Natural complex substances: From molecules to the molecular complexes. Analytical and technological advances for their definition and differentiation from the corresponding synthetic substances

Natural complex substances (NCSs) are a heterogeneous family of substances that are notably used as ingredients in several products classified as food supplements, medical devices, cosmetics and traditional medicines, according to the correspondent regulatory framework. The compositions of NCSs vary widely and hundreds to thousands of compounds can be present at the same time. A key concept is that NCSs are much more than the simple sum of the compounds that constitute them, in fact some emerging phenomena are the result of the supramolecular interaction of the constituents of the system. Therefore, close attention should be paid to produce and characterize these systems. Today many natural compounds are produced by chemical synthesis and are intentionally added to NCSs, or to formulated natural products, to enhance their properties, lowering their production costs. Market analysis shows a tendency of people to use products made with NCSs and, currently, products made with ingredients of natural origin only are not conveniently distinguishable from those containing compounds of synthetic origin. Furthermore, the uncertainty of the current European regulatory framework does not allow consumers to correctly differentiate and identify products containing only ingredients of natural origin. The high demand for specific and effective NCSs and their high-cost offer on the market, create the conditions to economically motivated sophistications, characterized by the addition of a cheap material to a more expensive one, just to increase profit. This type of practice can concern both the addition of less valuable natural materials and the addition of pure artificial compounds with the same structure as those naturally present. In this scenario, it becomes essential for producers of natural products to have advanced analytical techniques to evaluate the effective naturalness of NCSs. In fact, synthetically obtained compounds are not identical to their naturally occurring counterparts, due to the isotopic composition or chirality, as well as the presence of different trace metabolites (since pure substances in nature do not exist). For this reason, in this review, the main analytical tests that can be performed to differentiate natural compounds from their synthetic counterparts will be highlighted and the main analytical technologies will be described. At the same time, the main fingerprint techniques useful for characterizing the complexity of the NCSs, also allowing their identification and quali-quantitative evaluation, will be described. Furthermore, NCSs can be produced through different manufacturing processes, not all of which are on the same level of quality. In this review the most suitable technologies for green processes that operate according to physical extraction principles will be presented, as according to the authors they are the ones that come closest to creating more life-cycle compatible NCSs and that are well suited to the European green deal, a strategy with the aim of transforming the EU into a sustainable and resource-efficient society by 2050.

Lipid Peroxidation and Antioxidant Protection

Lipid peroxidation (LP) is the most important type of oxidative-radical damage in biological systems, owing to its interplay with ferroptosis and to its role in secondary damage to other biomolecules, such as proteins. The chemistry of LP and its biological consequences are reviewed with focus on the kinetics of the various processes, which helps understand the mechanisms and efficacy of antioxidant strategies. The main types of antioxidants are discussed in terms of structure-activity rationalization, with focus on mechanism and kinetics, as well as on their potential role in modulating ferroptosis. Phenols, pyri(mi)dinols, antioxidants based on heavy chalcogens (Se and Te), diarylamines, ascorbate and others are addressed, along with the latest unconventional antioxidant strategies based on the double-sided role of the superoxide/hydroperoxyl radical system.

Essential Oils: Chemistry and Pharmacological Activities

In this review, we provide an overview of the current understanding of the main mechanisms of pharmacological action of essential oils and their components in various biological systems. A brief introduction on essential oil chemistry is presented to better understand the relationship of chemical aspects with the bioactivity of these products. Next, the antioxidant, anti-inflammatory, antitumor, and antimicrobial activities are discussed. The mechanisms of action against various types of viruses are also addressed. The data show that the multiplicity of pharmacological properties of essential oils occurs due to the chemical diversity in their composition and their ability to interfere with biological processes at cellular and multicellular levels via interaction with various biological targets. Therefore, these natural products can be a promising source for the development of new drugs.

Essential Oils from Apiaceae, Asteraceae, Cupressaceae and Lamiaceae Families Grown in Serbia: Comparative Chemical Profiling with In Vitro Antioxidant Activity

The aim of the present study was to investigate the chemical profile and antioxidant activity of essential oils obtained from the most commonly grown plant species in Serbia. Aromatic and medicinal plants from Lamiaceae (Mentha x Piperita, Ocimum basilicum, Origanum majorana, Origanum vulgare, Salvia officinalis, Satureja hortensis, Satureja montana and Thymus vulgaris), Asteraceae (Ehinacea purpurea and Matricaria chamomilla), Apiaceae (Anethum graveolens, Carum carvi, Foeniculum vulgare, Petroselinum crispum and Pimpinella anisum) and Cupressaceae (Juniperus comunis) were selected as raw material for essential oils (EOs)' isolation. Hydrodistillation (HD) was used for the isolation of EOs while they were evaluated in terms of yield and terpenoid profiles by GC-MS. In vitro radical scavenging DPPH and ABTS⁺ radical activities were carried out for all EOs. Finally, a principal component analysis (PCA) was performed with the experimental results of the composition and antioxidant activity of the EOs, which showed a clear distinction between the selected plant species for the aforementioned responses. This work represents a screening tool for the selection of other EO candidates for further processing by emerging extraction techniques and the use of EOs as natural additives for meat products.

Plant Essential Oils as Healthy Functional Ingredients of Nutraceuticals and Diet Supplements: A Review

Essential oils (EOs) are mixtures of volatile molecules endowed with health-promoting biological activities that go beyond their role as aromas and natural preservatives and can be exploited to develop functional foods and diet supplements. Their composition is briefly addressed along with regulatory aspects. The potential health benefit of human diet supplementation with EOs is outlined through a review of the recent literature on available clinical trials and preclinical research concerning EOs activity towards: (1) irritable bowel syndrome; (2) inflammatory bowel disease; (3) regulation of microbiota; (4) gastroprotection; (5) hepatoprotection; (6) protection of the urinary tract and diuresis; (7) management of metabolic disorders including hyperglycemia and hyperlipidemia; (8) anti-inflammatory and pain control; (9) immunomodulation and protection from influenza; and (10) neuroprotection and modulation of mood and cognitive performance. The emerging potential in such activities of selected EOs is given focus, particularly green and black cumin, bergamot, orange, myrtle, peppermint, sage, eucalyptus, lavender, thyme, lemon balm, ginger, and garlic.

Kinetic Analysis of High-Temperature Sunflower Oil Peroxidation Inhibited by the Major Families of Phenolic Antioxidants Unveils the Extraordinary Activity of 1,4-Hydroquinones

Peroxidation of vegetable oils represents a major problem for the food and biodiesel industries, and it is greatly accelerated by oil degree of unsaturation and by temperature increase. Phenols represent the most common additives used to counteract oil peroxidation, however clear structure-activity relationships at high temperatures are not available. We report, herein, a kinetic study of O2 consumption during spontaneous peroxidation of sunflower oil at 130 °C in the presence of 18 antioxidants belonging to the main families of natural and synthetic phenols, including α-tocopherol, alkylphenols (BHT, BHA), hydroquinones (TBHD), catechols (quercetin, catechin) and gallates. Results show that TBHQ provide the best protection in terms of induction period (IP) duration and O2 consumption rate. EPR spectroscopy demonstrated that the inhibition activity is negatively correlated to the stability of the phenoxyl radical of the antioxidant (A•), suggesting that chain propagation with linoleate (RH) moieties A• + RH → AH + R• decreases the efficacy of those antioxidants forming persistent A• radicals. These results provide important information to optimize the antioxidant activity of phenols and of novel phenol-based materials.

Oxidizability of Oils Recovered from Olive Seeds by Isothermal Calorimetry

This work aims to apply isothermal calorimetry for the determination of the oxidative stability of bulk oils by deriving kinetic and thermodynamic parameters. The method consists of measuring the heat flow produced during the oxidation of the oils in the presence of oxygen. To this purpose, an oil was recovered from olive seeds, the solid waste derived from the transformation of olives, by using two different technologies: supercritical carbon dioxide and mechanical press. The oxidative stability of both extracted oils was then compared with commercial sunflower, soybean, corn, and rice oils. The kinetic and thermodynamic parameters, obtained from the analysis of isothermal calorimetry traces at 60 °C, allowed the calculation of the oxidizability index obtaining the following ranking: olive seeds by supercritical carbon dioxide (3.55 ± 0.4 × 10−3 (s/M)0.5) > sunflower (3.42 ± 0.8 × 10−3 (s/M)0.5) > olive seeds by mechanical press (3.07 ± 0.3 × 10−3 (s/M)0.5) > soybean (2.44 ± 0.6 × 10−3 (s/M)0.5) > corn (1.11 ± 0.4 × 10−3 (s/M)0.5) > rice oils (0.98 ± 0.4 × 10−3 (s/M)0.5). The results were then supported with the analysis of total phenolic content, antioxidant activity, fatty acid profile, and peroxide values. Overall, the findings of the present study support the use of isothermal calorimetry as a direct and non-invasive technique for determining the oxidizability of bulk oils.

Oxidative Stress in the Pathogenesis of Aorta Diseases as a Source of Potential Biomarkers and Therapeutic Targets, with a Particular Focus on Ascending Aorta Aneurysms

Aorta diseases, such as ascending aorta aneurysm (AsAA), are complex pathologies, currently defined as inflammatory diseases with a strong genetic susceptibility. They are difficult to manage, being insidious and silent pathologies whose diagnosis is based only on imaging data. No diagnostic and prognostic biomarkers or markers of outcome have been known until now. Thus, their identification is imperative. Certainly, a deep understanding of the mechanisms and pathways involved in their pathogenesis might help in such research. Recently, the key role of oxidative stress (OS) on the pathophysiology of aorta disease has emerged. Here, we describe and discuss these aspects by revealing some OS pathways as potential biomarkers, their underlying limitations, and potential solutions and approaches, as well as some potential treatments.