Phytosterol organic acid esters: Characterization, anti-inflammatory properties and a delivery strategy to improve mitochondrial function

Phytosterol organic acid esters are important food resources and the components of biomembrane structure. Due to the lack of extraction and synthesis techniques, more research has been focused on phytosterols, and the research on phytosterol acid esters have encountered a bottleneck, but phytosterol acid esters confer substantial benefits to human health. In this study, stigmasteryl vanillate (VAN), stigmasteryl protocatechuate (PRO) and stigmasteryl sinapate (SIN) were prepared through the Steglich reaction. The processes are promotable and the products reach up to 95% purity. In addition, their stability was evaluated by differential scanning calorimetry and thermogravimetric analysis. HPLC analysis revealed an enhancement in water solubility after esterification with phenolic acid. In an in vitro digestion model, the bioaccessibility of stigmasteryl phenolates was significantly higher than that of stigmasterols (STIs). Regarding the anti-inflammatory properties, VAN, PRO, and SIN exhibit superior effects against TNF-α induced pro-inflammatory responses compared to STI. All stigmasteryl phenolates supplementation increased the ATP production, the basal, and maximal oxygen consumption rate in mitochondrial stress test. Overall, we present a synthesis method for stigmasteryl phenolates. It will contribute to the development and research of phytosterol acid ester analysis, functions and utilization in food. Moreover, the nutrient-stigmasterol hybrids tactic we have constructed is practical and can become a targeted mitochondrial delivery strategy with enhanced anti-inflammatory effects.

Sterol, tocopherol, and bioactive fatty acid differences between conventional, high-quality, and organic cow milk

Milk contains several components that are important for human nutrition and health. To date, studies on organic and conventional milk have focused on their gross composition and fatty acid content, but little attention has been paid to the differences between other minor components, such as sterols and vitamins that may have functional actions. The aim of this study was to investigate the nutritional differences among 3 types of milk from a dairy plant: conventional, high-quality, and organic (in compliance with European regulations) milk, focusing on minor components such as sterols of animal and plant origin (phytosterols), tocopherols, and bioactive fatty acids. Cholesterol ranged from 271.37 mg/100 g of fat in conventional milk to 278.76 mg/100 g of fat in organic milk. Lanosterol was the main minor animal sterol in cow milk (ranging from 3.41 to 4.37 mg/100 g of fat), followed by desmosterol. The amount of total plant sterols in the analyzed milk ranged from 4.43 mg/100 g of fat in organic to 4.71 mg/100 g of fat in high-quality milk. Brassicasterol was the main sterol of plant origin which varied from 2.6 mg/100 g of fat in conventional and organic milk, to 2.93 mg/100 g of fat in high-quality milk. The second most present phytosterol was β-sitosterol, which ranged from 0.86 mg/100 g of fat in conventional to 0.97 mg/100 g of fat in high-quality, and organic milk. The results of the study showed no significant differences in gross and sterol composition between the 3 types of milk. However, the only significant difference found was in the fatty acid profile, with a higher n-3 content found in high-quality milk than in conventional and organic milk. These findings suggest that the investigated product categories and labels have minimal effect on the sterol and fatty acid profile of commercial cow milk.

Suitability of Banana and Plantain Fruits in Modulating Neurodegenerative Diseases: Implicating the In Vitro and In Vivo Evidence from Neuroactive Narratives of Constituent Biomolecules

Active principles in plant-based foods, especially staple fruits, such as bananas and plantains, possess inter-related anti-inflammatory, anti-apoptotic, antioxidative, and neuromodulatory activities. Neurodegenerative diseases affect the functionality of the central and peripheral nervous system, with attendant cognitive deficits being hallmarks of these conditions. The dietary constitution of a wide range of bioactive compounds identified in this review further iterates the significance of the banana and plantain in compromising, halting, or preventing the pathological mechanisms of neurological disorders. The neuroprotective mechanisms of these biomolecules have been identified by using protein expression regulation and specific gene/pathway targeting, such as the nuclear and tumor necrosis factors, extracellular signal-regulated and mitogen-activated protein kinases, activator protein-1, and the glial fibrillary acidic protein. This review establishes the potential double-edged neuro-pharmacological fingerprints of banana and plantain fruits in their traditionally consumed pulp and less utilized peel component for human nutrition.

A comprehensive review of wheat phytochemicals: From farm to fork and beyond

The health benefits of whole wheat consumption can be partially attributed to wheat's phytochemicals, including phenolic acids, flavonoids, alkylresorcinols, carotenoids, phytosterols, tocopherols, and tocotrienols. It is of increasing interest to produce whole wheat products that are rich in bioactive phytochemicals. This review provides the fundamentals of the chemistry, extraction, and occurrence of wheat phytochemicals and includes critical discussion of several long-lasting issues: (1) the commonly used nomenclature on distribution of wheat phenolic acids, namely, soluble-free, soluble-conjugated, and insoluble-bound phenolic acids; (2) different extraction protocols for wheat phytochemicals; and (3) the chemistry and application of in vitro antioxidant assays. This review further discusses recent advances on the effects of genotypes, environments, field management, and processing techniques including ultrafine grinding, germination, fermentation, enzymatic treatments, thermal treatments, and food processing. These results need to be interpreted with care due to varied sample preparation protocols and limitations of in vitro assays. The bioaccessibility, bioavailability, metabolism, and potential health benefits of wheat phytochemicals are also reviewed. This comprehensive and critical review will benefit scientific researchers in the field of bioactive compounds of cereal grains and also those in the cereal food industry to produce high-quality functional foods.

Connecting the Dots Between Hypercholesterolemia and Alzheimer’s Disease: A Potential Mechanism Based on 27-Hydroxycholesterol

Alzheimer’s disease (AD), the most common cause of dementia, is a complex and multifactorial disease involving genetic and environmental factors, with hypercholesterolemia considered as one of the risk factors. Numerous epidemiological studies have reported a positive association between AD and serum cholesterol levels, and experimental studies also provide evidence that elevated cholesterol levels accelerate AD pathology. However, the underlying mechanism of hypercholesterolemia accelerating AD pathogenesis is not clear. Here, we review the metabolism of cholesterol in the brain and focus on the role of oxysterols, aiming to reveal the link between hypercholesterolemia and AD. 27-hydroxycholesterol (27-OHC) is the major peripheral oxysterol that flows into the brain, and it affects β-amyloid (Aβ) production and elimination as well as influencing other pathogenic mechanisms of AD. Although the potential link between hypercholesterolemia and AD is well established, cholesterol-lowering drugs show mixed results in improving cognitive function. Nevertheless, drugs that target cholesterol exocytosis and conversion show benefits in improving AD pathology. Herbs and natural compounds with cholesterol-lowering properties also have a potential role in ameliorating cognition. Collectively, hypercholesterolemia is a causative risk factor for AD, and 27-OHC is likely a potential mechanism for hypercholesterolemia to promote AD pathology. Drugs that regulate cholesterol metabolism are probably beneficial for AD, but more research is needed to unravel the mechanisms involved in 27-OHC, which may lead to new therapeutic strategies for AD.

Dihydromyricetin Improves Cognitive Impairments in d-Galactose-Induced Aging Mice through Regulating Oxidative Stress and Inhibition of Acetylcholinesterase

SCOPE

Alzheimer's disease (AD) is a neurodegenerative disease with phenomena of cognitive impairments. Oxidative stress and cholinergic system dysfunction are two widely studied pathogenesis of AD. Dihydromyricetin (DMY) is a natural dihydroflavonol with many bioactivities. In this study, it is aimed to investigate the effects of DMY on cognitive impairment in d-galactose (d-gal) induced aging mice.

METHODS AND RESULTS

Mice are intraperitoneally injected with d-gal for 16 weeks, and DMY is supplemented in drinking water. The results show that DMY significantly improves d-gal-induced cognitive impairments in novel object recognition and Y-maze studies. H&E and TUNEL staining show that DMY could improve histopathological changes and cell apoptosis in mice brain. DMY effectively induces the activities of catalase, superoxide dismutase and glutathione peroxidase, and reduces malondialdehyde level in mice brain and liver. Furthermore, DMY reduces cholinergic injury by inhibiting the activity of Acetylcholinesterase (AChE) in mice brain. In vitro studies show that DMY is a non-competitive inhibitor of AChE with IC50 value of 161.2 µg mL^-1 .

CONCLUSION

DMY alleviates the cognitive impairments in d-gal-induced aging mice partly through regulating oxidative stress and inhibition of acetylcholinesterase.

Sterols and Sterol Oxidation Products: Effect of Dietary Intake on Tissue Distribution in ApoE-Deficient Mice

Sterols and sterol oxidation products (SOPs) are well-known dietary factors influencing atherosclerosis; however, their distribution in vivo after dietary sterol/SOP intake is still unclear. Here, we investigated the tissue distribution of sterols and SOPs in ApoE^-/- mice after dietary exposure to diets supplemented with phytosterols (PS), phytosterol oxidation products (POPs), or cholesterol oxidation products (COPs). The results showed that PS intake reduced cholesterol in serum and the liver but increased cholesterol in the brain. PS intake increased the levels of PS in vivo and the levels of 7-keto- and triol-POPs in serum and the liver. COP intake elevated the level of all COPs in serum but did not change the 7-keto-cholesterol level in the liver and brain. All POPs in serum and parts of POPs in the liver and brain increased after dietary POP exposure. Our study indicated that dietary PS and SOPs accumulated in vivo with varying degrees and influenced cerebral cholesterol metabolism.

Effects of Phytosterol Butyrate Ester on the Characteristics of Soybean Phosphatidylcholine Liposomes

The nutritional and structural properties of phytosterols (PS)/phytosterol esters (PEs) facilitate their use as substitutes for cholesterol in liposome encapsulation systems designed for oral drugs and health products. The purpose of this study was to determine the effect of phytosterol butyrate ester (PBE) on the properties of liposomes. PBE was encapsulated within liposomes (approximately 60 nm) prepared using soybean phosphatidylcholine using the thin-film hydration method. There was no significant change in the average particle diameter and zeta potential of these liposomal vesicles corresponding to the increasing amounts of encapsulated PBE. The incorporation of PBE increased the polydispersity index (PDI) independent of concentration. Additionally, we observed that the storage stability of PBE liposomes with uniform particle size and approximately spherical shape vesicle was better at low concentration. The results of Fourier-transform infrared (FTIR) spectroscopy and Raman spectroscopy showed that PBE was positioned at the water interface, which increased the order of hydrophobic alkyl chains in the lipid membranes. The incorporation of PBE led to an increase in the trans conformation of hydrophobic alkyl chain and consequently, the thermal stability of liposomes, which was confirmed by differential scanning calorimetry (DSC). The results of powder X-ray diffraction (XRD) analysis confirmed that PBE was present in an amorphous form in the liposomes. Additionally, the incorporation of PBE reduced the micropolarity of the lipid membrane. Thus, when preparing liposomes using thin-film hydration, the presence of PBE affected the characteristics of liposomes.

Phytosterols: Targeting Neuroinflammation in Neurodegeneration

Plant-derived sterols, phytosterols, are well known for their cholesterol-lowering activity in serum and their anti-inflammatory activities. Recently, phytosterols have received considerable attention due to their beneficial effects on various non-communicable diseases, and recommended use as daily dietary components. The signaling pathways mediated in the brain by phytosterols have been evaluated, but little is known about their effects on neuroinflammation, and no clinical studies have been undertaken on phytosterols of interest. In this review, we discuss the beneficial roles of phytosterols, including their attenuating effects on inflammation, blood cholesterol levels, and hallmarks of the disease, and their regulatory effects on neuroinflammatory disease pathways. Despite recent advancements made in phytosterol pharmacology, some critical questions remain unanswered. Therefore, we have tried to highlight the potential of phytosterols as viable therapeutics against neuroinflammation and to direct future research with respect to clinical applications.

Phytosterols: From Preclinical Evidence to Potential Clinical Applications

Phytosterols (PSs) are plant-originated steroids. Over 250 PSs have been isolated, and each plant species contains a characteristic phytosterol composition. A wide number of studies have reported remarkable pharmacological effects of PSs, acting as chemopreventive, anti-inflammatory, antioxidant, antidiabetic, and antiatherosclerotic agents. However, PS bioavailability is a key issue, as it can be influenced by several factors (type, source, processing, preparation, delivery method, food matrix, dose, time of administration into the body, and genetic factors), and the existence of a close relationship between their chemical structures (e.g., saturation degree and side-chain length) and low absorption rates has been stated. In this sense, the present review intends to provide in-depth data on PS therapeutic potential for human health, also emphasizing their preclinical effects and bioavailability-related issues.

Linking phytosterols and oxyphytosterols from food to brain health: origins, effects, and underlying mechanisms

Phytosterols and their oxidation products, namely oxyphytosterols, are natural compounds present in plant foods. With increased intake of phytosterol-enriched functional food products, the exposure of both phytosterols and oxyphytosterols is rising. Over the past ten years, researches have been focused on their absorption and metabolism in human body, as well as their biological effects. More importantly, recent studies showed that phytosterols and oxyphytosterols can traverse the blood-brain barrier and accumulate in the brain. As brain health problems resulting from ageing being more serious, attenuating central nervous system (CNS) disorders with active compounds in food are becoming a hot topic. Phytosterols and oxyphytosterols have been shown to implicated in cognition altering and the pathologies of several CNS disorders, including Alzheimer's disease and multiple sclerosis. We will overview these findings with a focus on the contents of phytosterols and oxyphytosterols in food and their dietary intake, as well as their origins in the brain, and illustrate molecular pathways through which they affect brain health, in terms of inflammation, cholesterol homeostasis, oxidative stress, and mitochondria function. The existing scientific gaps of phytosterols and oxyphytosterols to brain health in knowledge are also discussed, highlighting research directions in the future.

Himalayan Nettle Girardinia diversifolia as a Candidate Ingredient for Pharmaceutical and Nutraceutical Applications-Phytochemical Analysis and In Vitro Bioassays

Girardinia diversifolia, also known as Himalayan nettle, is a perennial herb used in Nepal to make fiber as well as in traditional medicine for the treatment of several diseases. To date, phytochemical studies and biological assays on this plant are scarce. Thus, in the present work, the G. diversifolia extracts have been evaluated for their potential pharmaceutical, cosmetic and nutraceutical uses. For this purpose, detailed phytochemical analyses were performed, evidencing the presence of phytosterols, fatty acids, carotenoids, polyphenols and saponins. The most abundant secondary metabolites were β- and γ-sitosterol (11 and 9% dw, respectively), and trans syringin (0.5 mg/g) was the most abundant phenolic. Fatty acids with an abundant portion of unsaturated derivatives (linoleic and linolenic acid at 22.0 and 9.7 mg/g respectively), vitamin C (2.9 mg/g) and vitamin B2 (0.12 mg/g) were also present. The antioxidant activity was moderate while a significant ability to inhibit acetylcholinesterase (AChE), butyrilcholinesterase (BuChE), tyrosinase, α-amylase and α-glucosidase was observed. A cytotoxic effect was observed on human ovarian, pancreatic and hepatic cancer cell lines. The effect in hepatocarcinoma cells was associated to a downregulation of the low-density lipoprotein receptor (LDLR), a pivotal regulator of cellular cholesterol homeostasis. These data show the potential usefulness of this species for possible applications in pharmaceuticals, nutraceuticals and cosmetics.

Maltol (3-Hydroxy-2-methyl-4-pyrone) Slows d-Galactose-Induced Brain Aging Process by Damping the Nrf2/HO-1-Mediated Oxidative Stress in Mice

Maltol, a maillard reaction product from ginseng (Panax ginseng C. A. Meyer), has been confirmed to inhibit oxidative stress in several animal models. Its beneficial effect on oxidative stress related brain aging is still unclear. In this study, the mouse model of d-galactose (d-Gal)-induced brain aging was employed to investigate the therapeutic effects and potential mechanisms of maltol. Maltol treatment significantly restored memory impairment in mice as determined by the Morris water maze tests. Long-term d-Gal treatment reduced expression of cholinergic regulators, i.e., the cholineacetyltransferase (ChAT) (0.456 ± 0.10 vs 0.211 ± 0.03 U/mg prot), the acetylcholinesterase (AChE) (36.4 ± 5.21 vs 66.5 ± 9.96 U/g). Maltol treatment prevented the reduction of ChAT and AChE in the hippocampus. Maltol decreased oxidative stress levels by reducing levels of reactive oxygen species (ROS) and malondialdehyde (MDA) production in the brain and by elevating antioxidative enzymes. Furthermore, maltol treatment minimized oxidative stress by increasing the phosphorylation levels of phosphatidylinositol-3-kinase (PI3K), protein kinase B (Akt), nuclear factor-erythroid 2-related factor 2 (Nrf2), and hemeoxygenase-1 (HO-1). The above results clearly indicate that supplementation of maltol diminishes d-Gal-induced behavioral dysfunction and neurological deficits via activation of the PI3K/Akt-mediated Nrf2/HO-1 signaling pathway in brain. Maltol might become a potential drug to slow the brain aging process and stimulate endogenous antioxidant defense capacity. This study provides the novel evidence that maltol may slow age-associated brain aging.

The Antioxidant and Anti-Aging Effects of Acetylated Mycelia Polysaccharides from Pleurotus djamor

The present work mainly describes the preparation of acetylated mycelia polysaccharides (AMPS) from Pleurotus djamor and investigates the antioxidant and anti-aging effects in d-galactose-induced aging mice. The optimized procedure indicates the acetyl substitution degree of AMPS is 0.54 ± 0.04 under the conditions of a reaction time of 56 h, a reaction temperature of 37 °C, and 4 mL of added acetic anhydride. The in vitro analysis and in vivo animal experiments indicate that the AMPS could alleviate the aging properties by scavenging the radicals, elevating the enzyme activities, and reducing the lipid contents. As for serum levels, the AMPS can improve the serum biochemical indices and enhance immunological activity. The histopathological observations indicate that the injuries to the liver, kidney, and brain can be remitted by AMPS intervention. The characterization showed that AMPS was one kind of β-pyranose with the weight-average molecular weights of 3.61 × 105 Da and the major monosaccharides of mannose and glucose. The results suggest that AMPS can be used as a dietary supplement and functional food for the prevention of aging and age-related diseases.

Major compounds of red ginseng oil attenuate Aβ25-35-induced neuronal apoptosis and inflammation by modulating MAPK/NF-κB pathway

β-Amyloid (Aβ)-induced neuronal toxicity in Alzheimer's disease (AD) is associated with complex mechanisms. Thus, a multi-target approach might be suitable for AD treatment. Following our previous study on the neuroprotective effects of red ginseng oil extract, its major compounds, including linoleic acid (LA), β-sitosterol (BS), and stigmasterol (SS), were examined to elucidate the mechanism of anti-apoptosis and anti-inflammation in Aβ25-35-stimulated PC12 cells. The results showed that the three compounds mitigated Aβ25-35 toxicity by regulating oxidative stress, apoptotic responses, and pro-inflammatory mediators. LA and SS strongly regulated intrinsic apoptosis markers, such as mitochondrial membrane potential, intracellular Ca2+, Bax/Bcl-2 ratio, and caspases-9, -3, and -8. However, BS blocked only the intrinsic apoptotic pathway, particularly by suppressing Ca2+ accumulation. Furthermore, all three compounds downregulated iNOS and phospho-nuclear factor-κB, but only LA and SS inhibited the expression of cyclooxygenase-2 and phospho-IκB. In assays to evaluate MAPK expression for confirming upstream signal pathways, BS decreased the phosphorylation of p38 and ERK, but not JNK, while SS markedly decreased the phosphorylation of all three MAPKs, and LA clearly decreased the phosphorylation of ERK and JNK, but not p38. These results indicate that LA, BS, and SS act as neuroprotectives against Aβ25-35-induced injury by distinct molecular mechanisms, indicating their preventive and/or therapeutic potential to treat AD.

Increased Levels of 27-Hydroxycholesterol Induced by Dietary Cholesterol in Brain Contribute to Learning and Memory Impairment in Rats

SCOPE

Dietary cholesterol has been shown to play a role in the development of Alzheimer's disease (AD). It is proposed that oxysterol especially 27-hydroxycholesterol (27-OHC) may play a potential role in β-amyloid peptides (Aβ) production and accumulation during AD progression.

METHODS AND RESULTS

To investigate the mechanisms of dietary cholesterol and 27-OHC on learning and memory impairment, male Sprague-Dawley rats are fed with cholesterol diet with or without 27-OHC synthetase inhibitor (anastrozole) injection. The levels of cholesterol, 27-OHC, 24-hydroxycholesterol (24S-OHC), 7α-hydroxycholesterol, and 7β-hydroxycholesterol in plasma are determined; apolipoprotein A (ApoA), apolipoprotein B (ApoB), HDL-cholesterol (HDL-C), and LDL-cholesterol (LDL-C) in plasma or brain; CYP27A1 and CYP7A1 in liver and CYP46A1 and CYP7B1 in brain; cathepsin B, cathepsin D, and acid phosphatase in lysosome; and Aβ1-40 and Aβ1-42 in brain. Results show increased levels of 27-OHC (p < 0.01), LDL-C (p < 0.01), and ApoB (p < 0.01), and decreased level of HDL-C (p < 0.05) in plasma, upregulated CYP27A1 (p < 0.01) and CYP7A1 (p < 0.01) expression in liver, altered lysosomal function, and increased level of Aβ in brain (p < 0.05).

CONCLUSIONS

This study indicates that the mechanisms of dietary cholesterol on learning and memory impairment may be involved in cholesterol metabolism and lysosome function with the increase of plasma 27-OHC, thus resulting in Aβ formation and accumulation.