A Polyphenolic Complex Attenuates Inflammatory Response and Blood- Brain Barrier Disruption

Efficacy of a Spearmint (Mentha spicata L.) Extract as Nutritional Support in a Rat Model of Hypertensive Glaucoma

Purpose

Glaucoma is an eye-brain axis disorder characterized by loss of retinal ganglion cells (RGCs). Although the role of intraocular pressure (IOP) elevation in glaucoma has been established, the reduction of oxidative stress and inflammation has emerged as a promising target for neuronal tissue-supporting glaucoma management. Therefore, we evaluated the effect of a proprietary spearmint extract (SPE) on RGC density, activity, and neuronal health markers in a rat model of hypertensive glaucoma.

Methods

Animals were divided in four groups: untreated healthy control and three glaucomatous groups receiving orally administered vehicle, SPE-low dose, or SPE-high dose for 28 days. Ocular hypertension was induced through intracameral injection of methylcellulose at day 15. At day 29, rats underwent electroretinogram (ERG) recordings, and retinas were analyzed for RGC density and markers of neural trophism, oxidative stress, and inflammation.

Results

SPE exerted dose-dependent response benefits on all markers except for IOP elevation. SPE significantly improved RGC-related ERG responses, cell density, neurotrophins, oxidative stress, and inflammation markers. Also, in SPE-high rats, most of the parameters were not statistically different from those of healthy controls.

Conclusions

SPE, a plant-based, polyphenolic extract, could be an effective nutritional support for neuronal tissues.

Translational Relevance

These results suggest that SPE not only may be a complementary approach in support to hypotensive treatments for the management of glaucoma but may also serve as nutritional support in other ocular conditions where antioxidant, anti-inflammatory, and neuroprotective mechanism are often disrupted.

Oxidative stress as a bridge between age and stroke: A narrative review

Stroke is the third most common cause of death globally and a leading cause of disability. The cellular and molecular changes following stroke and causes of neuronal death are not fully understood, and there are few effective treatments currently available. A rapid increase in the levels of reactive oxygen species (ROS) post stroke can overwhelm antioxidant defenses and trigger a series of pathophysiologic events including the inflammatory response, blood-brain barrier (BBB) disruption, apoptosis, and autophagy, ultimately leading to neuron degeneration and apoptosis. It is thought that beyond a certain age, the ROS accumulation resulting from stroke increases the risk of morbidity and mortality. In the present review, we summarize the role of oxidative stress (OS) as a link between aging and stroke pathogenesis. We also discuss how antioxidants can play a beneficial role in the prevention and treatment of stroke by eliminating harmful ROS, delaying aging, and alleviating damage to neurons.

Polyphenols and Their Impact on the Prevention of Neurodegenerative Diseases and Development

It is well known that neurodegenerative diseases' development and progression are accelerated due to oxidative stress and inflammation, which result in impairment of mitochondrial function, cellular damage, and dysfunction of DNA repair systems. The increased consumption of antioxidants can postpone the development of these disorders and improve the quality of patients' lives who have already been diagnosed with neurodegenerative diseases. Prolonging life span in developed countries contributes to an increase in the incidence ratio of chronic age-related neurodegenerative disorders, such as PD (Parkinson's disease), AD (Alzheimer's disease), or numerous forms of age-related dementias. Dietary supplementation with neuroprotective plant-derived polyphenols might be considered an important element of healthy aging. Some polyphenols improve cognition, mood, visual functions, language, and verbal memory functions. Polyphenols bioavailability differs greatly from one compound to another and is determined by solubility, degree of polymerization, conjugation, or glycosylation resulting from chemical structure. It is still unclear which polyphenols are beneficial because their potential depends on efficient transport across the BBB (blood-brain barrier), bioavailability, and stability in the CNS (central nervous system). Polyphenols improve brain functions by having a direct impact on cells and processes in the CNS. For a direct effect, polyphenolic compounds must be able to overcome the BBB and accumulate in brain tissue. In this review, the latest achievements in studies (animal models and clinical trials) on the effect of polyphenols on brain activity and function are described. The beneficial impact of plant polyphenols on the brain may be summarized by their role in increasing brain plasticity and related cognition improvement. As reversible MAO (monoamine oxidase) inhibitors, polyphenols are mood modulators and improve neuronal self-being through an increase in dopamine, serotonin, and noradrenaline amounts in the brain tissue. After analyzing the prohealth effects of various eating patterns, it was postulated that their beneficial effects result from synergistic interactions between individual dietary components. Polyphenols act on the brain endothelial cells and improve the BBB's integrity and reduce inflammation, thus protecting the brain from additional injury during stroke or autoimmune diseases. Polyphenolic compounds are capable of lowering blood pressure and improving cerebral blood flow. Many studies have revealed that a nutritional model based on increased consumption of antioxidants has the potential to ameliorate the cognitive impairment associated with neurodegenerative disorders. Randomized clinical trials have also shown that the improvement of cognitive functions resulting from the consumption of foods rich in flavonoids is independent of age and health conditions. For therapeutic use, sufficient quantities of polyphenols must cross the BBB and reach the brain tissue in active form. An important issue in the direct action of polyphenols on the CNS is not only their penetration through the BBB, but also their brain metabolism and localization. The bioavailability of polyphenols is low. The most usual oral administration also conflicts with bioavailability. The main factors that limit this process and have an effect on therapeutic efficacy are: selective permeability across BBB, gastrointestinal transformations, poor absorption, rapid hepatic and colonic metabolism, and systemic elimination. Thus, phenolic compounds have inadequate bioavailability for human applications to have any beneficial effects. In recent years, new strategies have been attempted in order to exert cognitive benefits and neuroprotective effects. Converting polyphenols into nanostructures is one of the theories proposed to enhance their bioavailability. The following nanoscale delivery systems can be used to encapsulate polyphenols: nanocapsules, nanospheres, micelles, cyclodextrins, solid lipid nanoparticles, and liposomes. It results in great expectations for the wide-scale and effective use of polyphenols in the prevention of neurodegenerative diseases. Thus far, only natural polyphenols have been studied as neuroprotectors. Perhaps some modification of the chemical structure of a given polyphenol may increase its neuroprotective activity and transportation through the BBB. However, numerous questions should be answered before developing neuroprotective medications based on plant polyphenols.

A Randomized, Double-Blind, Placebo-Controlled Trial of a Polyphenol Botanical Blend on Sleep and Daytime Functioning

Despite the high prevalence of subclinical sleep disturbances, existing treatments are either potent prescription medications or over-the-counter supplements with minimal scientific support and numerous side effects. However, preliminary evidence shows that polyphenols such as rosmarinic acid and epigallocatechin gallate can support healthy sleep without significant side effects. Therefore, the present study examined whether a polyphenol botanical blend (PBB) could improve sleep and/or daytime functioning in individuals with subclinical sleep disturbances. A total of 89 individuals completed a double-blind, randomized trial of daily treatment with PBB (n = 43) or placebo (n = 46) 30 min before bed for 30 days. Participants were monitored for changes in sleep (by sleep diary and an activity tracker), mood, and neurocognitive functioning. After 30 days, PBB improved diary sleep quality (p = 0.008) and reduced insomnia severity (p = 0.044) when compared to placebo. No other changes in sleep outcomes were observed. Additionally, PBB did not impair neurocognitive functioning, and some improvement was noted in vigilant attention, working memory, and risk assessment. Among individuals with subclinical sleep disturbances, PBB improved sleep quality, insomnia severity, and neurocognitive functioning over placebo. These findings indicate that polyphenol compounds may be useful for improving certain aspects of sleep without compromising neurocognitive functioning.

Antioxidative effects of a novel dietary supplement Neumentix in a mouse stroke model

BACKGROUND

During an acute stroke, reactive oxygen species are overproduced and the endogenous antioxidative defense systems are disrupted. Therefore, antioxidative therapy can be a promising scheme to reduce the severity of stroke. Neumentix is a novel antioxidative supplement produced from a patented mint line and contains a high content of rosmarinic acid (RA). Although Neumentix has proven diverse efficacy and safety in clinical trials, its effect on strokes is unclear.

METHODS

Mice that were treated with Neumentix or vehicle for 14 days underwent transient middle cerebral artery occlusion (tMCAO) for 60 min. Mice were sacrificed 5 days after tMCAO.

RESULTS

Neumentix preserved body weight after tMCAO, showed a high antioxidative effect in serum, and reduced infarction volume compared to the vehicle. The expression of 4-hydroxy-2-nonenal, Nε-(carboxymethyl) lysine, and 8-hydroxy-2'-deoxyguanosine was reduced in Neumentix-treated mice.

CONCLUSION

The antioxidative effect of Neumentix was confirmed. This is the first report to demonstrate the antioxidative effect of Neumentix on strokes.