Biological effects of olive oil phenolic compounds on mitochondria

Antioxidant and anti-ageing effects of oleuropein aglycone in canine skeletal muscle cells

Reactive oxygen species (ROS) are normally produced in skeletal muscle. However, an imbalance in their regulatory systems can lead to their accumulation and ultimately to oxidative stress, which is one of the causes of the ageing process. Companion dogs share the same environment and lifestyle as humans, making them an excellent comparative model for the study of ageing, as well as they constitute a growing market for bioactive molecules that improve the quality of life of pets. The anti-ageing properties of oleuropein aglycone (OLE), a bioactive compound from olive leaves known for its antioxidant properties, were investigated in Myok9 canine muscle cell model. After incubation with OLE, senescence was induced in the canine cellular model by hydrogen peroxide (H2O2). Analyses were performed on cells after seven days of differentiation. The oxidative stress induced by H2O2 treatment on differentiated canine muscle cells led to a significant increase in ROS formation, which was reduced by OLE pretreatment alone or in combination with H2O2 by about 34% and 32%, respectively. Cells treated with H2O2 showed a 48% increase the area of senescent cells stained by SA-β-gal, while OLE significantly reduced the coloured area by 52%. OLE, alone or in combination with H2O2, showed a significant antioxidant activity, possibly through autophagy activation, as indicated by the expression of autophagic markers.

Phenolic metabolites as therapeutic in inflammation and neoplasms: molecular pathways explaining their efficacy

Polyphenols, also known as phenolic compounds, are chemical substances containing aromatic rings as well as at least two hydroxyl groups. Natural phenolic compounds exist widely in plants, which protect plants from ultraviolet radiation and other insults. Phenolic compounds have superior pharmacological and nutritional properties (antimicrobial, antibacterial, antiviral, anti-sclerosis, antioxidant, and anti-inflammatory activities), which have been paid more and more attention by the scientific community. Phenols can protect key cellular components from reactive free radical damage, which is mainly due to their property to activate antioxidant enzymes and alleviate oxidative stress and inflammation. It can also inhibit or isolate reactive oxygen species and transfer electrons to free radicals, thereby avoiding cell damage. It has a regulatory role in glucose metabolism, which has a promising prospect in the prevention and intervention of diabetes. It also prevents cardiovascular disease by regulating blood pressure and blood lipids. Polyphenols can inhibit cell proliferation by affecting Erk1/2, CDK, and PI3K/Akt signaling pathways. Polyphenols can function as enhancers of intrinsic defense systems, including superoxide dismutase (SOD) and glutathione peroxidase (GPX). Simultaneously, they can modulate multiple proteins and transcription factors, making them promising candidates in the investigation of anti-cancer medications. This review focuses on multiple aspects of phenolic substances, including their natural origins, production process, disinfection activity, oxidative and anti-inflammatory functions, and the effects of different phenolic substances on tumors.

Co-Extraction Technique Improves Functional Capacity and Health-Related Benefits of Olive Oils: A Mini Review

Olive oil, a fundamental component of the Mediterranean diet, is recognized as a functional food due to its health-promoting composition. The concentration of phenolic compounds in olive oil is influenced by various factors such as genetics, agro-climatic conditions, and technological processes. Therefore, to ensure an ideal intake of phenolics through the diet, it is recommended to produce functional enriched olive oil that contains a high concentration of bioactive compounds. The co-extraction technique is used to create innovative and differentiated products that promote the sensory and health-related composition of oils. To enrich olive oil, various natural sources of bioactive compounds can be used, including raw materials derived from the same olive tree such as olive leaves, as well as other compounds from plants and vegetables, such as herbs and spices (garlic, lemon, hot pepper, rosemary, thyme, and oregano). The development of functional enriched olive oils can contribute to the prevention of chronic diseases and improve consumers' quality of life. This mini-review compiles and discusses relevant scientific information related to the development of enriched olive oil using the co-extraction technique and its positive effects on the health-related composition of oils.

Hydroxytyrosol Interference with Inflammaging via Modulation of Inflammation and Autophagy

Inflammaging refers to a chronic, systemic, low-grade inflammation, driven by immune (mainly macrophages) and non-immune cells stimulated by endogenous/self, misplaced or altered molecules, belonging to physiological aging. This age-related inflammatory status is characterized by increased inflammation and decreased macroautophagy/autophagy (a degradation process that removes unnecessary or dysfunctional cell components). Inflammaging predisposes to age-related diseases, including obesity, type-2 diabetes, cancer, cardiovascular and neurodegenerative disorders, as well as vulnerability to infectious diseases and vaccine failure, representing thus a major target for anti-aging strategies. Phenolic compounds-found in extra-virgin olive oil (EVOO)-are well known for their beneficial effect on longevity. Among them, hydroxytyrosol (HTyr) appears to greatly contribute to healthy aging by its documented potent antioxidant activity. In addition, HTyr can modulate inflammation and autophagy, thus possibly counteracting and reducing inflammaging. In this review, we reference the literature on pure HTyr as a modulatory agent of inflammation and autophagy, in order to highlight its possible interference with inflammaging. This HTyr-mediated activity might contribute to healthy aging and delay the development or progression of diseases related to aging.

Protective Effect of Treated Olive Mill Wastewater on Target Bacteria and Mitochondrial Voltage-Dependent Anion-Selective Channel 1

Olive mill wastewater, a by-product of the olive oil industry, represents an important resource, rich in bioactive compounds with antioxidant activity. In this study, two strategies to concentrate the bioactive components were used: the tangential membrane filtration (ultrafiltration and reverse osmosis) and the selective resin extraction. The concentrates were evaluated for physico-chemical characteristics and antioxidant activity. Furthermore, the antimicrobial activity and the effect on the mitochondrial voltage-dependent anion selective channel 1 were evaluated. The chemical results highlighted that the highest concentration of hydroxytyrosol (as 7204 mg/L) was revealed in the sample obtained by inverse osmosis while the highest concentration of oleuropein (10005 mg/L) was detected in the sample obtained by resin extraction. The latter sample exhibited the highest antimicrobial effects against Listeria monocytogenes, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. Both samples exhibited a high impact on the electrophysiological parameters of VDAC1 activity. These results showed that both valorization techniques, which can be reproduced at industrial scale, provided phenolic concentrates with antioxidant and antimicrobial activity useful for different future perspectives.

Gut microbiota, pathogenic proteins and neurodegenerative diseases

As the world's population ages, neurodegenerative diseases (NDs) have brought a great burden to the world. However, effective treatment measures have not been found to alleviate the occurrence and development of NDs. Abnormal accumulation of pathogenic proteins is an important cause of NDs. Therefore, effective inhibition of the accumulation of pathogenic proteins has become a priority. As the second brain of human, the gut plays an important role in regulate emotion and cognition functions. Recent studies have reported that the disturbance of gut microbiota (GM) is closely related to accumulation of pathogenic proteins in NDs. On the one hand, pathogenic proteins directly produced by GM are transmitted from the gut to the central center via vagus nerve. On the other hand, The harmful substances produced by GM enter the peripheral circulation through intestinal barrier and cause inflammation, or cross the blood-brain barrier into the central center to cause inflammation, and cytokines produced by the central center cause the production of pathogenic proteins. These pathogenic proteins can produced by the above two aspects can cause the activation of central microglia and further lead to NDs development. In addition, certain GM and metabolites have been shown to have neuroprotective effects. Therefore, modulating GM may be a potential clinical therapeutic approach for NDs. In this review, we summarized the possible mechanism of NDs caused by abnormal accumulation of pathogenic proteins mediated by GM to induce the activation of central microglia, cause central inflammation and explore the therapeutic potential of dietary therapy and fecal microbiota transplantation (FMT) in NDs.

Influence of Age and Dose on the Effect of Resveratrol for Glycemic Control in Type 2 Diabetes Mellitus: Systematic Review and Meta-Analysis

Background: Several clinical trials have suggested that resveratrol has hypoglycemic properties; however, there are other studies in which such an effect has not been observed. Methods: We carried out a systematic search in several databases; seventeen studies were selected for the systematic review and fifteen were included in the meta-analysis. Results: Resveratrol decreases glucose levels in subjects aged 45−59 years at doses <250 mg/day (−8.64 mg/dL, p < 0.00001), 250−500 mg/day (−22.24 mg/dL, p = 0.0003), and 500−1000 mg/day (−28.40 mg/dL, p = 0.0008), while in subjects older than 60 years, it only decreases with doses of 250−500 mg/day. Likewise, HbA1c improved in subjects aged 45−59 years with doses of 250−500 mg (−0.60%, p < 0.00001), but not in subjects older than 60 years. Insulin levels improved in subjects aged 45−59 years with doses < 250 mg/day (−0.80 mIU/L, p = 0.0003) and doses of 250−500 mg/day (−5.0 mIU/L, p = 0.0003), although in subjects older than 60 years, they only improved with doses of 250−500 mg/day (−1.79 mIU/L, p = 0.01). On the other hand, HOMA-IR only improved in subjects older than 60 years with doses of 250−500 mg/day (−0.40, p = 0.01). Conclusions: Resveratrol has a statistically significant dose−response effect on glucose concentrations, HbA1c, and insulin levels; however, there is not enough scientific evidence to propose a therapeutic dose.