Bioavailable Phenolic Compounds from Olive Pomace Present Anti-Neuroinflammatory Potential on Microglia Cells

Exploitation of Natural By-Products for the Promotion of Healthy Outcomes in Humans: Special Focus on Antioxidant and Anti-Inflammatory Mechanisms and Modulation of the Gut Microbiota

Daily, a lot of food is wasted, and vegetables, fruit, and cereals as well as marine products represent the major sources of unwanted by-products. The sustainability, waste recovery, and revalorization of food by-products have been proposed as the main goals of the so-called circular economy. In fact, food wastes are enriched in by-products endowed with beneficial effects on human health. Grape, olives, vegetables, and rice contain different compounds, such as polyphenols, dietary fibers, polysaccharides, vitamins, and proteins, which exert antioxidant and anti-inflammatory activities, inhibiting pro-oxidant genes and the Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-kβ) pathway, as demonstrated by in vitro and in vivo experiments. Dietary fibers act upon the gut microbiota, expanding beneficial bacteria, which contribute to healthy outcomes. Furthermore, marine foods, even including microalgae, arthropods, and wastes of fish, are rich in carotenoids, polyphenols, polyunsaturated fatty acids, proteins, and chitooligosaccharides, which afford antioxidant and anti-inflammatory protection. The present review will cover the major by-products derived from food wastes, describing the mechanisms of action involved in the antioxidant and anti-inflammatory activities, as well as the modulation of the gut microbiota. The effects of some by-products have also been explored in clinical trials, while others, such as marine by-products, need more investigation for their full exploitation as bioactive compounds in humans.

Levosimendan and Dobutamin Attenuate LPS-Induced Inflammation in Microglia by Inhibiting the NF-κB Pathway and NLRP3 Inflammasome Activation via Nrf2/HO-1 Signalling

Hypovolemic shock is a circulatory failure, due to a loss in the effective circulating blood volume, that causes tissue hypoperfusion and hypoxia. This condition stimulates reactive oxygen species (ROS) and pro-inflammatory cytokine production in different organs and also in the central nervous system (CNS). Levosimendan, a cardioprotective inodilator, and dobutamine, a β1-adrenergic agonist, are commonly used for the treatment of hypovolemic shock, thanks to their anti-inflammatory and antioxidant effects. For this reason, we aimed at investigating levosimendan and dobutamine's neuroprotective effects in an "in vitro" model of lipopolysaccharide (LPS)-induced neuroinflammation. Human microglial cells (HMC3) were challenged with LPS (0.1 µg/mL) to induce an inflammatory phenotype and then treated with levosimendan (10 µM) or dobutamine (50 µM) for 24 h. Levosimendan and dobutamine significantly reduced the ROS levels and markedly increased Nrf2 and HO-1 protein expression in LPS-challenged cells. Levosimendan and dobutamine also decreased p-NF-κB expression and turned off the NLRP3 inflammasome together with its downstream signals, caspase-1 and IL-1β. Moreover, a reduction in TNF-α and IL-6 expression and an increase in IL-10 levels in LPS-stimulated HMC3 cells was observed following treatment. In conclusion, levosimendan and dobutamine attenuated LPS-induced neuroinflammation through NF-κB pathway inhibition and NLRP3 inflammasome activation via Nrf2/HO-1 signalling, suggesting that these drugs could represent a promising therapeutic approach for the treatment of neuroinflammation consequent to hypovolemic shock.

Nutraceutical potential of olive pomace: insights from cell-based and clinical studies

Olive oil production yields a substantial volume of by-products, constituting up to 80% of the processed fruits. The olive pomace by-product represents a residue of significant interest due to the diverse bioactive compounds identified in it. However, a thorough characterization and elucidation of the biological activities of olive pomace are imperative to redirect its application for functional food, nutraceutical, and pharmaceutical purposes both for animals and humans. In this review, we examine data from experimental models, including immortalized human vascular endothelial cells, human corneal and conjunctival epithelial cells, human colorectal adenocarcinoma cells, non-tumorigenic human hepatoma cells, and murine macrophages alongside clinical trials. These studies aim to validate the safety, nutritional value, and pharmacological effects of olive pomace. In vitro studies suggest that biophenols extracted from olive pomace possess antioxidant, anti-inflammatory, and antiproliferative properties that could be beneficial in mitigating cardiovascular disorders, particularly atherosclerosis, hepatosteatosis, and dry-eye disease. Protective effects against dry-eye disease were confirmed in a mouse model assay. Olive pomace used in the feed for fish and poultry has demonstrated the ability to enhance animals' immunity and improve nutritional quality of meat and eggs. Human clinical trials are scarce and have revealed minimal biological changes following the consumption of olive pomace-enriched foods. However, alterations in certain biomarkers tentatively suggest cardioprotective properties. The review underscores the value of olive pomace while addressing potential drawbacks and future perspectives, with a specific focus on the need for further investigation into the animal feed and human nutritional properties of olive pomace. © 2024 Society of Chemical Industry.