Anti-neuroinflammatory effects of a food-grade phenolic-enriched maple syrup extract in a mouse model of Alzheimer's disease.

Objectives: Alzheimer's disease (AD) is a growing global health crisis exacerbated by increasing life span and an aging demographic. Convergent lines of evidence, including genome-wide association studies, strongly implicate neuroinflammation in the pathogenesis of AD. Several dietary agents, including phenolic-rich foods, show promise for the prevention and/or management of AD, which in large part, has been attributed to their anti-inflammatory effects. We previously reported that a food-grade phenolic-enriched maple syrup extract (MSX) inhibited neuroinflammation in vitro but whether these effects are translatable in vivo remain unknown. Herein, we assessed MSX's ability to attenuate early neuroinflammation in a transgenic mouse model of AD.Methods: The effects of MSX on AD-related neuroinflammation was evaluated by orally administering MSX (100 and 200 mg/kg/day for 30 days) to the 3xTg-AD mouse model of AD. The expression of inflammatory markers in mouse brains were analyzed with LC-MS/MS with SWATH acquisition.Results: 3xTg-AD mice dosed orally with MSX have decreased expression of several inflammatory proteins, including, most notably, the AD risk-associated protein 'triggering receptor expressed on myeloid cells-2' (TREM2), and stimulator of interferon genes TMEM173, and suppressor of cytokine signaling-6 (SOCS6). However, this decrease in inflammation did not coincide with a decrease in pathogenic amyloid generation or lipid peroxidation.Discussion: These data demonstrate that oral administration of this maple syrup derived natural product reduces key neuroinflammatory indices of AD in the 3xTg-AD model of AD. Therefore, further studies to investigate MSX's potential as a dietary intervention strategy for AD prevention and/or management are warranted.

Hepatoprotective and anti-inflammatory effects of a standardized pomegranate (Punica granatum) fruit extract in high fat diet-induced obese C57BL/6 mice.

Diets rich in fats are linked to elevated systemic inflammation, which augments the progression of inflammatory-related disorders including non-alcoholic fatty liver disease (NAFLD) and neurodegenerative diseases. A phenolic-enriched pomegranate fruit extract (PE) was investigated for its hepatoprotective and anti-inflammatory effects in male C57BL/6 mice fed either a high-fat diet or a standard rodent diet with or without 1% of PE for 12 weeks. Mouse livers and hippocampi were evaluated for the expression of genes associated with NAFLD and inflammation by multiplexed gene analysis. PE alleviated diet-induced fatty liver and suppressed hepatic lipid regulating genes including Cd36, Fas, Acot2 and Slc27a1. In addition, PE suppressed gene expression of pro-inflammatory cytokines including Il-1α, Il-7, Il-11, Ifnα, Tnfα and Lepr in the hippocampi. Our findings support the protective effects of PE against high-fat diet-induced hepatic and neurological disease.

Thymocid®, a Standardized Black Cumin (Nigella sativa) Seed Extract, Modulates Collagen Cross-Linking, Collagenase and Elastase Activities, and Melanogenesis in Murine B16F10 Melanoma Cells.

Black cumin (Nigella sativa) seed extract has been shown to improve dermatological conditions, yet its beneficial effects for skin are not fully elucidated. Herein, Thymocid®, a chemically standardized black cumin seed extract, was investigated for its cosmeceutical potential including anti-aging properties associated with modulation of glycation, collagen cross-linking, and collagenase and elastase activities, as well as antimelanogenic effect in murine melanoma B16F10 cells. Thymocid® (50, 100, and 300 µg/mL) inhibited the formation of advanced glycation end-products (by 16.7-70.7%), collagen cross-linking (by 45.1-93.3%), collagenase activity (by 10.4-92.4%), and elastases activities (type I and III by 25.3-75.4% and 36.0-91.1%, respectively). In addition, Thymocid® (2.5-20 µg/mL) decreased melanin content in B16F10 cells by 42.5-61.6% and reduced cellular tyrosinase activity by 20.9% (at 20 µg/mL). Furthermore, Thymocid® (20 µg/mL for 72 h) markedly suppressed the mRNA expression levels of melanogenesis-related genes including microphthalmia-associated transcription factor (MITF), tyrosinase-related protein 1 (TYRP1), and TYRP2 to 78.9%, 0.3%, and 0.2%, respectively. Thymocid® (10 µg/mL) also suppressed the protein expression levels of MITF (by 15.2%) and TYRP1 (by 97.7%). Findings from this study support the anti-aging and antimelanogenic potential of Thymocid® as a bioactive cosmeceutical ingredient for skin care products.

Pomegranate ellagitannin-gut microbial-derived metabolites, urolithins, inhibit neuroinflammation in vitro.

OBJECTIVES: Urolithins, ellagitannin-gut microbial-derived metabolites, have been reported to mediate pomegranate's neuroprotective effects against Alzheimer's disease (AD), but there are limited data on their effects against neuroinflammation. Herein, we: (1) evaluated whether urolithins (urolithins A and B and their methylated derivatives) attenuate neuroinflammation in murine BV-2 microglia and human SH-SY5Y neurons, and (2) evaluated hippocampus of transgenic AD (R1.40) mice administered a pomegranate extract (PE; 100 or 200 mg/kg/day for 3 weeks) for inflammatory biomarkers. METHODS: Effects of urolithins (10 µM) on inflammatory biomarkers were evaluated in lipopolysaccharide (LPS)-stimulated BV-2 microglia. In a non-contact co-culture cell model, SH-SY5Y cell viability was assessed after exposure to media collected from LPS-BV-2 cells treated with or without urolithins. Effects of urolithins on apoptosis and caspase 3/7 and 9 release from H2O2-induced oxidative stress of BV-2 and SH-SY5Y cells were assessed. Hippocampal tissues of vehicle and PE-treated transgenic R1.40 mice were evaluated for gene expression of inflammatory biomarkers by qRT-PCR. RESULTS: Urolithins decreased media levels of nitric oxide, interleukin 6 (IL-6), prostaglandin E2, and tumor necrosis factor alpha from LPS-BV-2 microglia. In the co-culture cell model, media from LPS-BV-2 cells treated with urolithins preserved SH-SY5Y cell viability greater than media from cells treated without urolithins. Urolithins mitigated apoptosis and caspase 3/7 and 9 release from H2O2-induced oxidative stress of BV-2 and SH-SY5Y cells. While not statistically significant, inflammatory biomarkers (TNF-α, COX-2, IL-1, and IL-6) appeared to follow a decreasing trend in the hippocampus of high-dose PE-treated animals compared to controls. DISCUSSION: The attenuation of neuroinflammation by urolithins may contribute, in part, toward pomegranate's neuroprotective effects against AD.

Levodopa-Reduced Mucuna pruriens Seed Extract Shows Neuroprotective Effects against Parkinson's Disease in Murine Microglia and Human Neuroblastoma Cells, Caenorhabditis elegans, and Drosophila melanogaster.

Mucuna pruriens (Mucuna) has been prescribed in Ayurveda for various brain ailments including 'kampavata' (tremors) or Parkinson's disease (PD). While Mucuna is a well-known natural source of levodopa (L-dopa), published studies suggest that other bioactive compounds may also be responsible for its anti-PD effects. To investigate this hypothesis, an L-dopa reduced (<0.1%) M. pruriens seeds extract (MPE) was prepared and evaluated for its anti-PD effects in cellular (murine BV-2 microglia and human SH-SY5Y neuroblastoma cells), Caenorhabditis elegans, and Drosophila melanogaster models. In BV-2 cells, MPE (12.5⁻50 µg/mL) reduced hydrogen peroxide-induced cytotoxicity (15.7-18.6%), decreased reactive oxygen species production (29.1-61.6%), and lowered lipopolysaccharide (LPS)-induced nitric oxide species release by 8.9⁻60%. MPE (12.5-50 µg/mL) mitigated SH-SY5Y cell apoptosis by 6.9-40.0% in a non-contact co-culture assay with cell-free supernatants from LPS-treated BV-2 cells. MPE (12.5-50 µg/mL) reduced 6-hydroxydopamine (6-OHDA)-induced cell death of SH-SY5Y cells by 11.85⁻38.5%. Furthermore, MPE (12.5-50 µg/mL) increased median (25%) and maximum survival (47.8%) of C. elegans exposed to the dopaminergic neurotoxin, methyl-4-phenylpyridinium. MPE (40 µg/mL) ameliorated dopaminergic neurotoxin (6-OHDA and rotenone) induced precipitation of innate negative geotaxis behavior of D. melanogaster by 35.3 and 32.8%, respectively. Therefore, MPE contains bioactive compounds, beyond L-dopa, which may impart neuroprotective effects against PD.

Evaluation of Polyphenol Anthocyanin-Enriched Extracts of Blackberry, Black Raspberry, Blueberry, Cranberry, Red Raspberry, and Strawberry for Free Radical Scavenging, Reactive Carbonyl Species Trapping, Anti-Glycation, Anti-ß-Amyloid Aggregation, and Microglial Neuroprotective Effects.

Glycation is associated with several neurodegenerative disorders, including Alzheimer's disease (AD), where it potentiates the aggregation and toxicity of proteins such as ß-amyloid (Aß). Published studies support the anti-glycation and neuroprotective effects of several polyphenol-rich fruits, including berries, which are rich in anthocyanins. Herein, blackberry, black raspberry, blueberry, cranberry, red raspberry, and strawberry extracts were evaluated for: (1) total phenolic and anthocyanins contents, (2) free radical (DPPH) scavenging and reactive carbonyl species (methylglyoxal; MGO) trapping, (3) anti-glycation (using BSA-fructose and BSA-MGO models), (4) anti-Aß aggregation (using thermal- and MGO-induced fibrillation models), and, (5) murine microglia (BV-2) neuroprotective properties. Berry crude extracts (CE) were fractionated to yield anthocyanins-free (ACF) and anthocyanins-enriched (ACE) extracts. The berry ACEs (at 100 µg/mL) showed superior free radical scavenging, reactive carbonyl species trapping, and anti-glycation effects compared to their respective ACFs. The berry ACEs (at 100 µg/mL) inhibited both thermal- and MGO-induced Aß fibrillation. In addition, the berry ACEs (at 20 µg/mL) reduced H2O2-induced reactive oxygen species production, and lipopolysaccharide-induced nitric oxide species in BV-2 microglia as well as decreased H2O2-induced cytotoxicity and caspase-3/7 activity in BV-2 microglia. The free radical scavenging, reactive carbonyl trapping, anti-glycation, anti-Aß fibrillation, and microglial neuroprotective effects of these berry extracts warrant further in vivo studies to evaluate their potential neuroprotective effects against AD.

Isolation, Identification, and Biological Evaluation of Phenolic Compounds from a Traditional North American Confectionery, Maple Sugar.

Maple sap, collected from the sugar maple (Acer saccharum) tree, is boiled to produce the popular plant-derived sweetener, maple syrup, which can then be further evaporated to yield a traditional North American confectionery, maple sugar. Although maple sap and maple syrup have been previously studied, the phytochemical constituents of maple sugar are unknown. Herein, 30 phenolic compounds, 1-30, primarily lignans, were isolated and identified (by HRESIMS and NMR) from maple sugar. The isolates included the phenylpropanoid-based lignan tetramers (erythro,erythro)-4″,4‴-dihydroxy-3,3',3″,3‴,5,5'-hexamethoxy-7,9';7',9-diepoxy-4,8″;4',8‴-bisoxy-8,8'-dineolignan-7″,7‴,9″,9‴-tetraol, 29, and (threo,erythro)-4″,4‴-dihydroxy-3,3',3″,3‴,5,5'-hexamethoxy-7,9';7',9-diepoxy-4,8″;4',8‴-bisoxy-8,8'-dineolignan-7″,7‴,9″,9‴-tetraol, 30, neither of which have been identified from maple sap or maple syrup before. Twenty of the isolates (selected on the basis of sample quantity available) were evaluated for their potential biological effects against lipopolysaccharide-induced inflammation in BV-2 microglia in vitro and juglone-induced oxidative stress in Caenorhabditis elegans in vivo. The current study increases scientific knowledge of possible bioactive compounds present in maple-derived foods including maple sugar.

Cosmetic applications of glucitol-core containing gallotannins from a proprietary phenolic-enriched red maple (Acer rubrum) leaves extract: inhibition of melanogenesis via down-regulation of tyrosinase and melanogenic gene expression in B16F10 melanoma cells.

The red maple (Acer rubrum) is a rich source of phenolic compounds which possess galloyl groups attached to different positions of a 1,5-anhydro-D-glucitol core. While these glucitol-core containing gallotannins (GCGs) have reported anti-oxidant and anti-glycative effects, they have not yet been evaluated for their cosmetic applications. Herein, the anti-tyrosinase and anti-melanogenic effects of a proprietary phenolic-enriched red maple leaves extract [Maplifa™; contains ca. 45% ginnalin A (GA) along with other GCGs] were investigated using enzyme and cellular assays. The GCGs showed anti-tyrosinase activity with IC50 values ranging from 101.4 to 1047.3 µM and their mechanism of tyrosinase inhibition (using GA as a representative GCG) was evaluated by chelating and computational/modeling studies. GA reduced melanin content in murine melanoma B16F10 cells by 79.1 and 56.7% (at non-toxic concentrations of 25 and 50 µM, respectively), and its mechanisms of anti-melanogenic effects were evaluated by using methods including fluorescent probe (DCF-DA), real-time PCR, and western blot experiments. These data indicated that GA was able to: (1) reduce the levels of reactive oxygen species, (2) down-regulate the expression of MITF, TYR, TRP-1, and TRP-2 gene levels in a time-dependent manner, and (3) significantly reduce protein expression of the TRP-2 gene. Therefore, the anti-melanogenic effects of red maple GCGs warrant further investigation of this proprietary natural product extract for potential cosmetic applications.

Anti-glycation and anti-oxidative effects of a phenolic-enriched maple syrup extract and its protective effects on normal human colon cells.

Oxidative stress and free radical generation accelerate the formation of advanced glycation endproducts (AGEs) which are linked to several chronic diseases. Published data suggest that phenolic-rich plant foods, show promise as natural anti-AGEs agents due to their anti-oxidation capacities. A phenolic-enriched maple syrup extract (MSX) has previously been reported to show anti-inflammatory and neuroprotective effects but its anti-AGE effects remain unknown. Therefore, herein, we investigated the anti-glycation and anti-oxidation effects of MSX using biochemical and biophysical methods. MSX (500 µg mL-1) reduced the formation of AGEs by 40% in the bovine serum albumin (BSA)-fructose assay and by 30% in the BSA-methylglyoxal (MGO) assay. MSX also inhibited the formation of crosslinks typically seen in the late stage of glycation. Circular dichroism and differential scanning calorimeter analyses demonstrated that MSX maintained the structure of BSA during glycation. In the anti-oxidant assays, MSX (61.7 µg mL-1) scavenged 50% of free radicals (DPPH assay) and reduced free radical generation by 20% during the glycation process (electron paramagnetic resonance time scan). In addition, the intracellular levels of hydrogen peroxide induced reactive oxygen species were reduced by 27-58% with MSX (50-200 µg mL-1) in normal/non-tumorigenic human colon CCD-18Co cells. Moreover, in AGEs and MGO challenged CCD-18Co cells, higher cellular viabilities and rapid extracellular signal-regulated kinase (ERK) phosphorylation were observed in MSX treated cells, indicating its protective effects against AGEs-induced cytotoxicity. Overall, this study supports the biological effects of MSX, and warrants further investigation of its potential as a dietary agent against diseases mediated by oxidative stress and inflammation.

Bioactive Glucitol-Core Containing Gallotannins and other Phytochemicals from Silver Maple (Acer saccharinum) Leaves.

In the course of our group's investigation of members of the maple (Acer) genus, a series of glucitol-core containing gallotannins (GCGs) were-isolated and identified (by NMR and HREISMS). Among higher plants, only certain maple species are known to produce GCGs, compounds with potential nutraceutical and cosmetic applications due to their reported antioxidant, antidiabetic, anti-α-glucosidase, anti-glycation, anticancer, and skin. health promoting effects. Herein, we sought to investigate whether the previously un-investigated silver maple (Acer saccharinum) species was also a source of GCGs. Nine phenolic compounds, including six GCGs, were identified (by HPLC-DAD analyses using previously isolated standards) as ginnalins A-C (1-3), rnaplexins B, D, and F (4-6), methyl syringate (7), methyl gallate (8), and 3-methoxy-4-hydroxyphenol-1-ß-D-(6-galloyl)-glucopyranoside (9). In addition, one, sesquiterpenoid, namely, pubineroid A (10), was isolated and identified (by NMR).

Development of a neuroprotective potential algorithm for medicinal plants.

Medicinal plants are promising candidates for Alzheimer's disease (AD) research but there is lack of systematic algorithms and procedures to guide their selection and evaluation. Herein, we developed a Neuroprotective Potential Algorithm (NPA) by evaluating twenty-three standardized and chemically characterized Ayurvedic medicinal plant extracts in a panel of bioassays targeting oxidative stress, carbonyl stress, protein glycation, amyloid beta (Aß) fibrillation, acetylcholinesterase (AChE) inhibition, and neuroinflammation. The twenty-three herbal extracts were initially evaluated for: 1) total polyphenol content (Folin-Ciocalteu assay), 2) free radical scavenging capacity (DPPH assay), 3) ferric reducing antioxidant power (FRAP assay), 4) reactive carbonyl species scavenging capacity (methylglyoxal trapping assay), 5) anti-glycative effects (BSA-fructose, and BSA-methylglyoxal assays) and, 6) anti-Aß fibrillation effects (thioflavin-T assay). Based on assigned index scores from the initial screening, twelve extracts with a cumulative NPA score ≥40 were selected for further evaluation for their: 1) inhibitory effects on AChE activity, 2) in vitro anti-inflammatory effects on murine BV-2 microglial cells (Griess assay measuring levels of lipopolysaccharide-induced nitric oxide species), and 3) in vivo neuroprotective effects on Caenorhabditis elegans post induction of Aß1-42 induced neurotoxicity and paralysis. Among these, four extracts had a cumulative NPA score ≥60 including Phyllanthus emblica (amla; Indian gooseberry), Mucuna pruriens (velvet bean), Punica granatum (pomegranate) and Curcuma longa (turmeric; curcumin). These extracts also showed protective effects on H2O2 induced cytotoxicity in differentiated cholinergic human neuronal SH-SY5Y and murine BV-2 microglial cells and reduced tau protein levels in the SH-SY5Y neuronal cells. While published animal data support the neuroprotective effects of several of these Ayurvedic medicinal plant extracts, some remain unexplored for their anti-AD potential. Therefore, the NPA may be utilized, in part, as a strategy to help guide the selection of promising medicinal plant candidates for future AD-based research using animal models.