Natural Carotenoids as Neuroprotective Agents for Alzheimer's Disease: An Evidence-Based Comprehensive Review

Encapsulation Techniques of Carotenoids and Their Multifunctional Applications in Food and Health: An Overview

Carotenoids are a broad category of biologically active pigments in plants and animals with significant health associations, including immune-modulatory, anti-inflammatory, and antioxidant roles. They persuade prevention of illness through numerous mechanisms such as protection against oxidative stress, encouragement of cardiovascular and neuroprotective events, and reduction of diseases comprising cancer and macular degeneration. Carotenoids have several health benefits but are unstable, with low bioavailability, and easily degrade in environments containing light, heat, and oxygen. Since the encapsulation improves carotenoid solubility, stability, and controlled release, it has become a feasible strategy for overcoming these issues. This review considers a few encapsulation methods, including electrospinning, lipid-based delivery systems, spray drying, freeze drying, and supercritical fluid technology. Each of these methods is assessed in terms of their ability to retain carotenoids, improve bioavailability, and deliver targeted distribution. Evaluation of these methods has been made with the view of benefits, drawbacks, and suitability for industrial use. In conclusion, the analysis identifies current challenges in carotenoid encapsulation and potential future investigation and innovation directions in this area to exploit carotenoid-based functional foods, nutraceuticals, and medications.

Intermittent fasting applied in combination with astaxanthin alleviates D-galactose-induced aging in rats: Comparison in oxidative stress, immune response, and metabolomics

Effective anti-aging strategies involving dietary restriction and antioxidant supplementation are gaining increasing research attention, while the health effects of their combined intervention are rarely reported. In this study, for the first time, we investigated the anti-aging effects and underlying mechanisms of intermittent fasting (IF), astaxanthin (AX), and their combination in D-galactose-induced aging rats. Our results demonstrated that these three treatments effectively inhibited malondialdehyde levels and improved the activity of endogenous antioxidant enzymes in the brain, liver, and serum of aging rats. Simultaneously, the combination of IF and AX had a synergistic effect on the recovery of brain mitochondrial injury as evidenced by permeability transition pore openness, membrane potential, respiratory chain complex enzyme activity, and cortical and hippocampal lesions. Notably, the combination significantly increased the levels of Immunoglobulin M (55.66 ± 3.23%), immunoglobulin G (34.41 ± 2.65%), and IL-2 (23.49 ± 1.78%) compared with the model group. Moreover, AX reduced the accumulation of pro-inflammatory factor IL-6 (23.06 ± 2.02%), while the combination induced more remarkable reduction in the accumulation of IL-1β (35.92 ± 3.06%) in the serum. Considering the serum metabolomics analysis, we hypothesized that IF and AX played a positive role in the regulation of the nervous system, which was associated with the differential metabolites lysope 16:0, N-Acety-L-tyrosine, and L-Alanyl-L-Lysine. This research reveals that the combination therapy provided synergistic anti-aging efficacy by enhancing resistance to oxidative stress, ameliorating mitochondrial dysfunction, and restoring the immune system. These findings might have significant implications for further studies on the exploration of effective anti-aging therapy.

Neuroprotective effect of apo-9'-fucoxanthinone against cerebral ischemia injury by targeting the PI3K/AKT/GSK-3β pathway

Neuronal loss in cerebral ischemia primarily results from the combined effects of inflammatory responses and programmed cell death. Currently, there is an urgent need for potent neuroprotectants targeting both inflammatory and apoptotic responses for the treatment of ischemic stroke. Marine natural products are a vital source of novel drug candidates. Apo-9'-fucoxanthinone (APO-9'), a degradation product of fucoxanthin derived from marine brown algae, is known for its substantial anti-inflammatory effects, yet its neuroprotective action has not been clearly defined. In this study, the neuroprotective effects of APO-9' in alleviating cerebral ischemia injury and the underlying mechanism were primarily explored with the aid of tandem mass tag-based quantitative proteomics. APO-9' was found to markedly decrease the levels of inflammation factors by suppressing the IKK/IκB/NF-κB pathway in lipopolysaccharide (LPS)-induced BV2 cells. It also attenuated apoptotic responses in both LPS-induced BV2 cells and oxygen-glucose deprivation/reoxygenation (OGD/R)-induced SH-SY5Y cells. These neuroprotective effects of APO-9' were linked to the activation of the PI3K/AKT pathway. Intraperitoneal injection of APO-9' in a MCAO mouse model showed significant cerebral protection against ischemia. The involvements of the IKK/IκB/NF-κB and PI3K/AKT/GSK-3β pathways were also confirmed in its alleviation of cerebral ischemia in vivo. This study established that APO-9' exerted neuroprotection against cerebral ischemia by inhibiting inflammatory and apoptotic cascades via the IKK/IκB/NF-κB and PI3K/AKT/GSK-3β signaling pathways.

Carotenoids for Antiaging: Nutraceutical, Pharmaceutical, and Cosmeceutical Applications

Background: Carotenoids are bioactive tetraterpenoid C40 pigments that are actively synthesized by plants, bacteria, and fungi. Compounds such as α-carotene, β-carotene, lycopene, lutein, astaxanthin, β-cryptoxanthin, fucoxanthin, and zeaxanthin have attracted increasing attention for their antiaging properties. They exhibit antioxidant, neuroprotective, and anti-inflammatory properties, contributing to the prevention and treatment of age-related diseases. Objectives: The aim of this study was to comprehensively analyze the pharmacological potential and biological mechanisms of carotenoids associated with age-related disorders and to evaluate their application in nutraceuticals, pharmaceuticals, and cosmeceuticals. Methods: A systematic review of studies published over the past two decades was conducted using the databases PubMed, Scopus, and Web of Science. The selection criteria included clinical, in silico, in vivo, and in vitro studies investigating the pharmacological and therapeutic effects of carotenoids. Results: Carotenoids demonstrate a variety of health benefits, including the prevention of age-related macular degeneration, cancer, cognitive decline, metabolic disorders, and skin aging. Their role in nutraceuticals is well supported by their ability to modulate oxidative stress and inflammatory pathways. In pharmaceuticals, carotenoids show promising results in formulations targeting neurodegenerative diseases and metabolic disorders. In cosmeceuticals, they improve skin health by protecting it against UV radiation and oxidative damage. However, bioavailability, optimal dosages, toxicity, and interactions with other bioactive compounds remain critical factors to maximize therapeutic efficacy and still require careful evaluation by scientists. Conclusions: Carotenoids are promising bioactive compounds for antiaging interventions with potential applications in a variety of fields. Further research is needed to optimize their formulas, improve bioavailability, and confirm their long-term safety and effectiveness, especially in the aging population.

Bee Pollen as a Source of Biopharmaceuticals for Neurodegeneration and Cancer Research: A Scoping Review and Translational Prospects

Bee Pollen (BP) has many advantageous properties relying on its multitargeting potential, a new tendency in managing many challenging illnesses. In cancer and neurodegeneration, the multiple effects of BP could be of unequaled importance and need further investigation. Although still limited, available data interestingly spotlights some floral sources with promising activities in line with this investigation. Adopting scoping review methodology, we have identified many crucial bioactivities that are widely recognized to individual BP compounds but remain completely untapped in this valuable bee cocktail. A wide range of these compounds have been recently found to be endowed with great potential in modulating pivotal processes in neurodegeneration and cancer pathophysiology. In addition, some ubiquitous BP compounds have only been recently isolated, while the number of studied BPs remains extremely limited compared to the endless pool of plant species worldwide. We have also elucidated that clinical profits from these promising perspectives are still impeded by challenging hurdles such as limited bioavailability of the studied phytocompounds, diversity and lack of phytochemical standardization of BP, and the difficulty of selective targeting in some pathophysiological mechanisms. We finally present interesting insights to guide future research and pave the way for urgently needed and simplified clinical investigations.

4-Hydroxydictyolactone alleviates cerebral ischemia injury by regulating neuroinflammation and autophagy via AMPK signaling pathway

BACKGROUND

Cerebral ischemia (CI), a cerebrovascular disorder, is a major contributor to disability and mortality. Marine-derived compounds are an important source of new neuroprotective drug candidates. Xenicane-type diterpenes from brown algae of the genus Dictyota have exhibited potential neuroprotective effects against CI injury, attributed to their antioxidant properties. However, whether there are other underlying neuroprotective mechanisms of xenicane diterpenes against CI is still ambiguous.

PURPOSE

This study aims to elucidate the neuroprotective efficacy and mechanism of 4-hydroxydictyolactone (HDTL) in the treatment of CI.

METHODS

The LPS-induced BV2 cell model was used for anti-neuroinflammatory activity assay. Tandem Mass Tag (TMT)-based quantitative proteomics was employed to identify underlying mechanisms. The OGD/R-induced SH-SY5Y cell model and a MCAO mice model were used to assess the neuroprotective effect of HDTL against CI in vitro and in vivo.

RESULTS

HDTL reduced inflammation in LPS-stimulated BV2 cells by inhibiting the IKK/IκB/NF-κB pathway and by enhancing AMPK phosphorylation. Additionally, in SH-SY5Y cells treated with OGD/R, HDTL facilitated autophagy and reduced apoptosis. The neuroprotective properties of HDTL were abrogated in AMPK- silenced SH-SY5Y cells. In MCAO mice, HDTL ameliorated CI injury as evidenced by decreases in neurological deficit scores and cerebral infarction. HDTL also promoted autophagy and reduced apoptosis in vivo through both the AMPK/mTOR and IKK/IκB/NF-κB pathways.

CONCLUSION

HDTL exhibits neuroprotective effects through regulating the AMPK/mTOR and IKK/IκB/NF-κB pathways. These findings suggest that HDTL is a promising therapeutic candidate for CI treatment.

Carotenoid Supplementation for Alleviating the Symptoms of Alzheimer's Disease

Alzheimer's disease (AD) is characterized by, among other things, dementia and a decline in cognitive performance. In AD, dementia has neurodegenerative features and starts with mild cognitive impairment (MCI). Research indicates that apoptosis and neuronal loss occur in AD, in which oxidative stress plays an important role. Therefore, reducing oxidative stress with antioxidants is a natural strategy to prevent and slow down the progression of AD. Carotenoids are natural pigments commonly found in fruits and vegetables. They include lipophilic carotenes, such as lycopene, α- and β-carotenes, and more polar xanthophylls, for example, lutein, zeaxanthin, canthaxanthin, and β-cryptoxanthin. Carotenoids can cross the blood-brain barrier (BBB) and scavenge free radicals, especially singlet oxygen, which helps prevent the peroxidation of lipids abundant in the brain. As a result, carotenoids have neuroprotective potential. Numerous in vivo and in vitro studies, as well as randomized controlled trials, have mostly confirmed that carotenoids can help prevent neurodegeneration and alleviate cognitive impairment in AD. While carotenoids have not been officially approved as an AD therapy, they are indicated in the diet recommended for AD, including the consumption of products rich in carotenoids. This review summarizes the latest research findings supporting the potential use of carotenoids in preventing and alleviating AD symptoms. A literature review suggests that a diet rich in carotenoids should be promoted to avoid cognitive decline in AD. One of the goals of the food industry should be to encourage the enrichment of food products with functional substances, such as carotenoids, which may reduce the risk of neurodegenerative diseases.

Ultrasound-based strategies for the recovery of microalgal carotenoids: Insights from green extraction methods to UV/MS-based identification

Carotenoids, versatile natural pigments with numerous health benefits, face environmental concerns associated with conventional petrochemical-based extraction methods and limitations of their synthetic equivalents. In this context, this study aims to introduce eco-friendly approaches using ultrasound-based strategies (probe and bath) for the extraction of carotenoids from microalgae, initially focusing on Microchloropsis gaditana and subsequently evaluating the versatility of the method by applying it to other microalgae species of interest (Tisochrysis lutea, Porphyridium cruentum, and Phaeodactylum tricornutum) and defatted microalgal residues. Among the approaches evaluated, the 5-min ultrasonic probe system with ethanol showed comparable carotenoid recovery efficiency to the reference method (agitation, 24 h, acetone) (9.4 ± 2.5 and 9.6 ± 3.2 mg g-1 carotenoids per dry biomass, for the green and the reference method, respectively). Moreover, the method's sustainability was demonstrated using the AGREEprep™ software (scored 0.62 out of 1), compared to the traditional method (0.22 out of 1). The developed method yielded high carotenoid contents across species with diverse cell wall compositions (3.1 ± 0.2, 2.1 ± 0.3, and 4.1 ± 0.1 mg g-1 carotenoid per dry biomass for T. lutea, P. cruentum, and P. tricornutum, respectively). Moreover, the application of the method to defatted biomass showed potential for microalgal valorization with carotenoid recovery rates of 41 %, 60 %, 61 %, and 100 % for M.gaditana, P. tricornutum, T. lutea, and P. cruentum, compared to the original biomass, respectively. Furthermore, by using high-performance liquid chromatography with a diode array detector (HPLC-DAD) and high-resolution mass spectrometry (HRMS), we reported the carotenoid and chlorophyll profiles of the different microalgae and evaluated the impact of the eco-friendly methods. The carotenoid and chlorophyll profiles varied depending on the species, biomass, and method used. In summary, this study advances a green extraction method with improved environmental sustainability and shorter extraction time, underscoring the potential of this approach as a valuable alternative for the extraction of microalgal pigments.

The inhibitory effects of endophytic metabolites on glycated proteins under non-communicable disease conditions: A review

Protein glycation in human body is closely linked to the onset/progression of diabetes associated complications. These glycated proteins are commonly known as advanced glycation end products (AGEs). Recent literature has also highlighted the involvement of AGEs in other non-communicable diseases (NCDs) such as cardiovascular, cancer, and Alzheimer's diseases and explored the impact of plant metabolites on AGEs formation. However, the significance of endophytic metabolites against AGEs has recently garnered attention but has not been thoroughly summarized thus far. Therefore, the objective of this review is to provide a comprehensive overview of the importance of endophytic metabolites in combating AGEs under NCDs conditions. Additionally, this review aims to elucidate the processes of AGEs formation, absorption, metabolism, and their harmful effects. Collectively, endophytic metabolites play a crucial role in modulating signaling pathways and enhancing the digestibility properties of gut microbiota (GM) by targeting on AGEs/RAGE (receptor for AGEs) axis. Furthermore, these metabolites exhibit anti-AGEs activities similar to those derived from host plants, but at a lower cost and higher production rate. The use of endophytes as a source of such metabolites offers a risk-free and sustainable approach that holds substantial potential for the treatment and management of NCDs.

Potential neuroprotective benefits of plant-based fermented foods in Alzheimer's disease: an update on preclinical evidence

Alzheimer's disease (AD) currently lacks effective treatments, making its prevention a critical focus. While accumulating evidence supports that plant-based fermented foods may contribute to AD prevention, the neuroprotective effect of plant-based fermented foods on AD has not been comprehensively reviewed. In this study, we conducted a systematic review of preclinical studies on the efficacy of plant-based fermented foods in AD. The literature search was based on databases including PubMed, Embase, Web of Science, and Scopus. The PICO approach was employed for report inclusion, and each report was assessed for risk of bias using the SYRCLE's RoB tool. From the analysis of 25 retrieved reports, we extracted essential details, including bibliographic information, animal models and characteristics, sources of plant-based fermented foods, dosages, administration routes, durations, and outcome measures. Our findings indicate that plant-based fermented foods may positively impact acute and long-term cognitive function, as well as beta-amyloid-mediated neurodegeneration. This review sheds light on the potential neuroprotective benefits of plant-based fermented foods for various AD-related aspects, including oxidative stress, synaptotoxicity, neuroinflammation, tau hyperphosphorylation, dysfunctional amyloidogenic pathways, and cognitive deficits, as observed in rodent models of AD. However, the small number of studies obtained from our literature search and the finding that many of them were of moderate methodological quality suggest the need for further investigation to substantiate the beneficial potential of this class of functional food for the management of AD.

Probing Antioxidant-Related Properties for Phenolic Compounds

In this work, properties related to antioxidant-potential mechanisms (such as the bond dissociation enthalpy, BDE, for the homolytic cleavage of the O-H bond and ionization energies, IEs) were determined for phenol, pyrocatechol, and gallic acid (GA). Both the protonated and deprotonated forms of GA were investigated. The Feller-Peterson-Dixon (FPD) composite method was employed with a variety of computational approaches, i.e., density functional theory, Möller-Plesset perturbation theory, and coupled-cluster-based methods, in combination with large correlation consistent basis sets with extrapolation to the complete basis set limit and consideration of core electron correlation effects. FPD results were compared to experimental and computational data available in the literature, presenting good agreement. For example, the FPD BDE (298 K) obtained for phenol, which was based on valence-correlated MP2/CBS calculations with contributions from correlating all electrons, was determined to be 87.56 kcal/mol, a value that is 0.42 kcal/mol lower than the result obtained in the most recent experiments, 87.98 ± 0.62. Calibration against coupled-cluster calculations was also carried out for phenol. We expect that the outcomes gathered here may help in establishing a general protocol for computational chemists that are interested in determining antioxidant-related properties for phenolic compounds with considerable accuracy as well as to motivate future IE measurements (particularly for GA) to be accomplished in the near future.

Preparation of trans-Crocetin with High Solubility, Stability, and Oral Bioavailability by Incorporation into Three Types of Cyclodextrins

Crocetin (CRT), an active compound isolated from saffron, exhibits several pharmacological activities, including anti-tumor and immune-regulatory activities, and is effective against myocardial ischemia and coronary heart disease; however, its low stability and solubility limit its clinical application. Therefore, we investigated CRT inclusion complexes (ICs) with three cyclodextrins-α-CD, HP-β-CD, and γ-CD-suitable for oral administration prepared using an ultrasonic method. Fourier transform infrared spectroscopy and powder X-ray diffraction indicated that the crystalline state of CRT in ICs disappeared, and intermolecular interactions were observed between CRT and CDs. 1H nuclear magnetic resonance and phase solubility studies confirmed CRT encapsulation in the CD cavity and the formation of ICs. In addition, we observed the morphology of ICs using scanning electron microscopy. All ICs showed a high drug encapsulation efficiency (approximately 90%) with 6500-10,000 times better solubilities than those of the pure drug. CRT showed rapid dissolution, whereas pure CRT was water-insoluble. The formation of ICs significantly improved the storage stability of CRT under heat, light, and moisture conditions. Further, the peak time of CRT in rats significantly decreased, and the relative bioavailability increased by approximately 3-4 times. In addition, the oral bioavailability of CRT IC was evaluated. Notably, the absorption rate and degree of the drug in rats were improved. This study illustrated the potential applications of CRT/CD ICs in the food, healthcare, and pharmaceutical industries, owing to their favorable dissolution, solubility, stability, and oral bioavailability.

Lycopene from Red Guava (Psidium guajava L.): From Hepatoprotective Effect to Its Use as Promising Self-Emulsifying Drug Delivery System for Anti-Inflammatory and Antioxidant Applications

Lycopene is a carotenoid with potential use in the treatment of chronic illnesses. Here, different formulations of lycopene were studied: lycopene-rich extract from red guava (LEG), purified lycopene from red guava (LPG) and a self-emulsifying drug delivery system loaded with LPG (nanoLPG). The effects of administering orally various doses of LEG to hypercholesterolemic hamsters were evaluated regarding the liver function of the animals. The cytotoxicity of LPG in Vero cells was analyzed by a crystal violet assay and by fluorescence microscopy. In addition, nanoLPG was employed in stability tests. LPG and nanoLPG were tested for their cytotoxic effect on human keratinocytes and antioxidant capacity on cells in an endothelial dysfunction model in an isolated rat aorta. Finally, the effect of different nanoLPG concentrations on the expression of immune-related genes (IL-10, TNF-α, COX-2 and IFN-γ) from peripheral blood mononuclear cells (PBMC) using real-time PCR was also analyzed. Results suggest that LEG, despite not being able to improve blood markers indicative of liver function in hypercholesterolemic hamsters, reduced hepatic degenerative changes. Additionally, LPG did not show cytotoxicity in Vero cells. In relation to nanoLPG, the effects produced by heat stress evaluated by Dynamics Light Scattering (DLS) and visually were loss of color, texture change and phase separation after 15 days without interfering with the droplet size, so the formulation proved to be efficient in stabilizing the encapsulated lycopene. Although LPG and nanoLPG showed moderate toxicity to keratinocytes, which may be related to cell lineage characteristics, both revealed potent antioxidant activity. LPG and nanoLPG showed vasoprotective effects in aortic preparations. The gene expression assay indicates that, although no significant differences were observed in the expression of IL-10 and TNF-α, the PBMCs treated with nanoLPG showed a reduction in transcriptional levels of IFN-γ and an increased expression of COX-2. Thus, the work adds evidence to the safety of the use of lycopene by humans and shows that tested formulations, mainly nanoLPG due to its stability, stand out as promising and biosafe products for the treatment of diseases that have oxidative stress and inflammation in their etiopathology.