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.

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.

Pomegranate shows neuroprotective effects against Alzheimer’s disease (AD) in several reported animal studies. However, whether its constituent ellagitannins and/or their physiologically relevant gut microbiota-derived metabolites, namely, urolithins (6H-dibenzo[b,d]pyran-6-one derivatives), are the responsible bioactive constituents is unknown. Therefore, from a pomegranate extract (PE), previously reported by our group to have anti-AD effects in vivo, 21 constituents, which were primarily ellagitannins, were isolated and identified (by HPLC, NMR, and HRESIMS). In silico computational studies, used to predict blood-brain barrier permeability, revealed that none of the PE constituents, but the urolithins, fulfilled criteria required for penetration. Urolithins prevented β-amyloid fibrillation in vitro and methyl-urolithin B (3-methoxy-6H-dibenzo[b,d]pyran-6-one), but not PE or its predominant ellagitannins, had a protective effect in Caenorhabditis elegans post induction of amyloid β1–42 induced neurotoxicity and paralysis. Therefore, urolithins are the possible brain absorbable compounds which contribute to pomegranate’s anti-AD effects warranting further in vivo studies on these compounds.Keywords: Alzheimer’s disease; blood-brain barrier; ellagitannins; microbial metabolites; Pomegranate; urolithins

The phenolic contents of plant foods are commonly quantified by the Folin–Ciocalteu assay based on gallic acid equivalents (GAEs). However, this may lead to inaccuracies because gallic acid is not always representative of the structural heterogeneity of plant phenolics. Therefore, product-specific standards have been developed for the phenolic quantification of several foods. Currently, maple-derived foods (syrup, sugar, sap/water, and extracts) are quantified for phenolic contents based on GAEs. Because lignans are the predominant phenolics present in maple, herein, a maple phenolic lignan-enriched standard (MaPLES) was purified (by chromatography) and characterized (by UFLC-MS/MS with lignans previously isolated from maple syrup). Using MaPLES and secoisolariciresinol (a commercially available lignan), the phenolic contents of the maple-derived foods increased 3-fold compared to GAEs. Therefore, lignan-based standards are more appropriate for phenolic quantification of maple-derived foods versus GAEs. Also, MaPLES can be utilized for the authentication and detection of fake label claims on maple products.

Glucitol-core containing gallotannins (GCGs) are polyphenols containing galloyl groups attached to a 1,5-anhydro-D-glucitol core, which is uncommon among naturally occurring plant gallotannins. GCGs have only been isolated from maple (Acer) species, including the red maple (Acer rubrum), a medicinal plant which along with the sugar maple (Acer saccharum), are the major sources of the natural sweetener, maple syrup. GCGs are reported to show antioxidant, α-glucosidase inhibitory, and antidiabetic effects, but their antiglycating potential is unknown. Herein, the inhibitory effects of five GCGs (containing 1–4 galloyls) on the formation of advanced glycation end-products (AGEs) were evaluated by MALDI-TOF mass spectroscopy, and BSA–fructose, and G.K. peptide-ribose assays. The GCGs showed superior activities compared to the synthetic antiglycating agent, aminoguanidine (IC50 15.8–151.3 vs. >300 μM) at the early, middle, and late stages of glycation. Circular dichroism data revealed that the GCGs were able to protect the secondary structure of BSA protein from glycation. The GCGs did not inhibit AGE formation by the trapping of reactive carbonyl species, namely, methylglyoxal, but showed free radical scavenging activities in the DPPH assay. The free radical quenching properties of the GCGs were further confirmed by electron paramagnetic resonance spectroscopy using ginnalin A (contains 2 galloyls) as a representative GCG. In addition, this GCG chelated ferrous iron, an oxidative catalyst of AGE formation, supported a potential antioxidant mechanism of antiglycating activity for these polyphenols. Therefore, GCGs should be further investigated for their antidiabetic potential given their antioxidant, α-glucosidase inhibitory, and antiglycating properties.

Maple syrup is a widely consumed plant-derived natural sweetener produced by concentrating xylem sap collected from certain maple (Acer) species. During thermal evaporation of water, natural phytochemical components are concentrated in maple syrup. The polymeric components from maple syrup were isolated by ethanol precipitation, dialysis, and anion exchange chromatography and structurally characterized by glycosyl composition analysis, glycosyl linkage analysis, and nuclear magnetic resonance spectroscopy. Among the maple syrup polysaccharides, one neutral polysaccharide was characterized as inulin with a broad molecular weight distribution, representing the first isolation of this prebiotic carbohydrate from a xylem sap. In addition, two acidic polysaccharides with structural similarity were identified as arabinogalactans derived from rhamnogalacturonan type I pectic polysaccharides.Keywords: arabinogalactan; inulin; maple syrup; polysaccharide;

Published data supports the neuroprotective effects of several phenolic-containing natural products, including certain fruit, berries, spices, nuts, green tea, and olive oil. However, limited data are available for phenolic-containing plant-derived natural sweeteners including maple syrup. Herein, we investigated the neuroprotective effects of a chemically standardized phenolic-enriched maple syrup extract (MSX) using a combination of biophysical, in vitro, and in vivo studies. Based on biophysical data (Thioflavin T assay, transmission electron microscopy, circular dichroism, dynamic light scattering, and zeta potential), MSX reduced amyloid β1−42 peptide (Aβ1−42) fibrillation in a concentration-dependent manner (50–500 μg/mL) with similar effects as the neuroprotective polyphenol, resveratrol, at its highest test concentration (63.5 % at 500 μg/mL vs. 77.3 % at 50 μg/mL, respectively). MSX (100 μg/mL) decreased H2O2-induced oxidative stress (16.1 % decrease in ROS levels compared to control), and down-regulated the production of lipopolysaccharide (LPS)-stimulated inflammatory markers (22.1, 19.9, 74.8, and 87.6 % decrease in NOS, IL-6, PGE2, and TNFα levels, respectively, compared to control) in murine BV-2 microglial cells. Moreover, in a non-contact co-culture cell model, differentiated human SH-SY5Y neuronal cells were exposed to conditioned media from BV-2 cells treated with MSX (100 μg/mL) and LPS or LPS alone. MSX-BV-2 media increased SH-SY5Y cell viability by 13.8 % compared to media collected from LPS-BV-2 treated cells. Also, MSX (10 μg/mL) showed protective effects against Aβ1−42 induced neurotoxicity and paralysis in Caenorhabditis elegans in vivo. These data support the potential neuroprotective effects of MSX warranting further studies on this natural product.

•A phenolic-free fraction was purified from American cranberry (Vaccinium macrocarpon).•Constituents of the fraction were predominantly composed of oligosaccharides with various degrees of polymerisation.•Glycosyl composition and linkage analyses and NMR data revealed mainly xyloglucan and arabinan residues.•The oligosaccharide constituents reduced biofilm formation by uropathogenic E. coli by over 50%.•Cranberry oligosaccharides may play a role in its preventive effects against urinary tract infections.The preventive effects of the American cranberry (Vaccinium macrocarpon) against urinary tract infections are supported by extensive studies which have primarily focused on its phenolic constituents. Herein, a phenolic-free carbohydrate fraction (designated cranf1b-F2) was purified from cranberry fruit using ion exchange and size exclusion chromatography. MALDI-TOF-MS analysis revealed that the cranf1b-F2 constituents are predominantly oligosaccharides possessing various degrees of polymerisation and further structural analysis (by GC–MS and NMR) revealed mainly xyloglucan and arabinan residues. In antimicrobial assays, cranf1b-F2 (at 1.25 mg/mL concentration) reduced biofilm production by the uropathogenic Escherichia coli CFT073 strain by over 50% but did not inhibit bacterial growth. Cranf1b-F2 (ranging from 0.625 to 10 mg/mL) also inhibited biofilm formation of the non-pathogenic E. coli MG1655 strain up to 60% in a concentration-dependent manner. These results suggest that cranberry oligosaccharides, in addition to its phenolic constituents, may play a role in its preventive effects against urinary tract infections.

Gallotannins containing a glucitol core, which are only produced by members of the maple (Acer) genus, are more potent α-glucosidase inhibitors than the clinical drug, acarbose. While this activity is influenced by the number of substituents on the glucitol core (e.g. more galloyl groups leads to increased activity), the mechanisms of inhibitory action are not known. Herein, we investigated ligand–enzyme interactions and binding mechanisms of a series of ‘glucitol-core containing gallotannins (GCGs)’ against the α-glucosidase enzyme. The GCGs included ginnalins A, B and C (containing two, one, and one galloyl/s, respectively), maplexin F (containing 3 galloyls) and maplexin J (containing 4 galloyls). All of the GCGs were noncompetitive inhibitors of α-glucosidase and their interactions with the enzyme were further explored using biophysical and spectroscopic measurements. Thermodynamic parameters (by isothermal titration calorimetry) revealed a 1:1 binding ratio between GCGs and α-glucosidase. The binding regions between the GCGs and α-glucosidase, probed by a fluorescent tag, 1,1′-bis(4-anilino-5-naphthalenesulfonic acid), revealed that the GCGs decreased the hydrophobic surface of the enzyme. In addition, circular dichroism analyses showed that the GCGs bind to α-glucosidase and lead to loss of the secondary α-helix structure of the protein. Also, molecular modeling was used to predict the binding site between the GCGs and the α-glucosidase enzyme. This is the first study to evaluate the mechanisms of inhibitory activities of gallotannins containing a glucitol core on α-glucosidase.

Glycation is a spontaneous process initiated by a condensation reaction between reducing sugars and proteins that leads to the formation of advanced glycation endproducts (AGEs). The in vivo accumulation of AGEs is associated with several chronic human diseases and, thus, the search for AGE inhibitors is of great research interest. Hydrolyzable tannins (gallotannins and ellagitannins) are bioactive plant polyphenols which show promise as natural inhibitors of glycation and AGE formation. Notably, the gallotannin, 1,2,3,4,6-penta-O-galloyl-β-D-glucose (PGG), is a key intermediate involved in the biosynthesis of hydrolyzable tannins in plants. Herein, we investigated the effects of PGG on the individual stages of protein glycation and on protein structure (using bovine serum albumin; BSA). MALDI-TOF data demonstrated that PGG inhibited early glycation by 75% while the synthetic AGE inhibitor, aminoguanidine (AG), was not active (both at 50 μM). In addition, PGG reduced the formation of middle and late stage AGEs by 90.1 and 60.5%, respectively, which was superior to the positive control, AG. While glycation induced conformational changes in BSA from α-helix to β-sheets (from circular dichroism and congo red binding studies), PGG (at 50 μM) reduced this transition by 50%. Moreover, BSA treated with PGG was more stable in its structure and retained its biophysical properties (based on zeta potential and electrophoretic mobility measurements). The interaction between PGG and BSA was further supported by molecular docking studies. Overall, the current study adds to the growing body of data supporting the anti-AGE effects of hydrolyzable tannins, a ubiquitous class of bioactive plant polyphenols.

Cumin (Cuminum cyminum L.), a widely consumed food spice, has been reported to have antiglycative effects in vitro and in vivo, but there is a paucity of data on its bioactive compounds. Herein, we report the isolation and structure elucidation (by NMR, HRESIMS, and CD) of 21 (1–21) compounds from a methanol extract of cumin seeds. The isolates included five new compounds: two sesquiterpenoids, two pairs of monoterpeneoid epimers, and a chalcone, named cuminoids A–E, respectively. The isolates were evaluated for antiglycative effects using the bovine serum albumin–fructose intrinsic fluorescence assay. At equivalent concentrations, several of the isolates, including cuminoids C–E, were more potent inhibitors than the positive control, aminoguanidine, a synthetic antiglycative agent (>50 vs 35%, respectively).

Six rare naturally occurring indazole-type alkaloids including two new compounds, 17-O-(β-d-glucopyranosyl)-4-O-methylnigellidine (1) and nigelanoid (2), and four known compounds (3–6) were isolated from a defatted extract of Nigella sativa (black cumin) seeds. 17-O-(β-d-Glucopyranosyl)-4-O-methylnigellidine (1) increased glucose consumption by liver hepatocytes (HepG2 cells) through activation of AMP-activated protein kinase (AMPK). Also, this is the first report of compounds 4 and 6 from a natural source.

•The anti-inflammatory mechanism of a maple syrup extract is proposed.•It reduces nitric oxide and prostaglandin-E2 levels.•It inhibits nitric oxide synthase gene and protein expression.•This inhibition is a result of suppression of NF-κB transcriptional activation.•Phenolics in maple syrup extract are effective in decreasing inflammatory markers.The in vitro anti-inflammatory effects of a phenolic-enriched Canadian maple syrup ethyl acetate extract (MS-EtOAc) and 15 purified phenolic constituents were evaluated in a LPS-stimulated RAW 264.7 murine macrophage cell model. MS-EtOAc decreased nitric oxide (NO) and prostaglandin-E2 (PGE2) production at 10–100 μg/mL concentrations. The observed NO inhibition was a direct result of reduced nitric oxide synthase (iNOS) protein and gene expression through suppression of NF-κB transcriptional activation. In addition, MS-EtOAc upregulated cyclooxygenase-2 (COX-2) mRNA and protein expression. Among the 15 pure isolates, (E)-3,3′-dimethoxy-4,4′-dihydroxystilbene was most effective in decreasing both NO and PGE2 levels. However, 4-acetylcatechol, tyrosol, and protocatechuic acid only reduced PGE2 levels. Thus, the potential anti-inflammatory activity of MS-EtOAc can be attributed to its unique combination of compounds and not as a result of a single purified phenolic constituent alone. Future research on the purified phenolic compounds will be useful in understanding the overall in vitro anti-inflammatory effects of maple syrup.

The fifth biennial Berry Health Benefits Symposium showcased recent research supporting the positive effects of berry consumption on human health and disease. Remarkably, the vast majority of oral papers covered data accumulated from in vivo studies, which underscores how berry health research has advanced since the inception of this symposium in 2005. Similar to the past, research presented at this meeting was primarily focused on the major commercially cultivated berries in North America, namely, blackberry, blueberry, black raspberry, cranberry, red raspberry, and strawberry. Despite this, on the basis of similar compositional chemistry, it is possible that similar biological effects may also be extended to other small soft-fleshed “berry-type” fruits popular in other parts of the world including Europe, Asia, and South America. Overall, this symposium continues to add to the growing body of data supporting the positive impact of berry fruit consumption on human health promotion and disease risk reduction.

Maple syrup has nutraceutical potential given the macronutrients (carbohydrates, primarily sucrose), micronutrients (minerals and vitamins), and phytochemicals (primarily phenolics) found in this natural sweetener. We conducted compositional (ash, fiber, carbohydrates, minerals, amino acids, organic acids, vitamins, phytochemicals), in vitro biological, and in vivo safety (animal toxicity) studies on maple syrup extracts (MSX-1 and MSX-2) derived from two declassified maple syrup samples. Along with macronutrient and micronutrient quantification, thirty-three phytochemicals were identified (by HPLC-DAD), and nine phytochemicals, including two new compounds, were isolated and identified (by NMR) from MSX. At doses of up to 1000 mg/kg/day, MSX was well tolerated with no signs of overt toxicity in rats. MSX showed antioxidant (2,2-diphenyl-1-picrylhydrazyl (DPPH) assay) and anti-inflammatory (in RAW 264.7 macrophages) effects and inhibited glucose consumption (by HepG2 cells) in vitro. Thus, MSX should be further investigated for potential nutraceutical applications given its similarity in chemical composition to pure maple syrup.

Polyphenols are bioactive compounds found in plant foods. Ginnalins A–C are polyphenols present in the sap and other parts of the sugar and red maple species which are used to produce maple syrup. Here we evaluated the antiproliferative effects of ginnalins A–C on colon (HCT-116) and breast (MCF-7) tumourigenic and non-tumourigenic colon (CCD-18Co) cells and investigated whether these effects were mediated through cell cycle arrest and/or apoptosis. Ginnalins A–C were twofold more effective against the tumourigenic than non-tumourigenic cells. Among the polyphenols, ginnalin A (84%, HCT-116; 49%, MCF-7) was more effective than ginnalins B and C (50%, HCT-116; 30%, MCF-7) at 50 μM concentrations. Ginnalin A did not induce apoptosis of the cancer cells but arrested cell cycle (in the S- and G2/M-phases) and decreased cyclins A and D1 protein levels. These results suggest that maple polyphenols may have potential cancer chemopreventive effects mediated through cell cycle arrest.Highlights► Ginnalins-A–C are polyphenols present in maple plant species. ► Ginnalins inhibited growth of human cancer but not non-tumorigenic cells. ► Ginnalins did not induce apoptosis of cancer cells but arrested cell cycle. ► Ginnalins decreased cyclins-A and D1 protein levels of cancer cells.

•Maple sap phenolics and antioxidant activities are preserved after pasteurization.•Maple sap phenolics and antioxidant activities are preserved after sterilization.•Over 25 phenolics were observed in both sap samples and 16 were identified.•Maple sap should be investigated for functional beverage applications.Maple sap has been consumed for centuries as a tonic by the indigenous peoples of eastern North America but is primarily utilized in this region to produce maple syrup. The natural watery form of maple sap makes its application as a functional beverage appealing but due to microbial growth, sterilization or pasteurization would be necessary before sap could be consumed. This study was designed to investigate the chemical composition (sugars, amino acids, organic acids, minerals, and phenolics) and antioxidant effects of maple sap after undergoing pasteurization and sterilization. After both processes, sugars, amino acids, organic acids, and minerals were preserved in the sap samples and they had similar phenolic contents (0.25–0.27 mg/100 g gallic acid equivalents) and antioxidant activities (IC50 ca. 550 μg/mL by DPPH assay). HPLC-DAD analyses revealed over 25 constituents in the sap samples of which 15 were identified using phenolic standards. In addition, one compound, 3′,5′-dimethoxy-4′-hydroxy-(2-hydroxy)acetophenone, not previously reported from maple syrup, was isolated and identified (by NMR) for the first time from maple sap. Therefore, the preservation of chemical constituents and antioxidant activity in maple sap after pasteurization and sterilization warrants its application as a functional beverage beyond its primary use for maple syrup production alone.

Two new ellagitannins containing a rare 3-oxo-1,3,3a,8b-tetrahydrofuro[3,4-b]benzofuran moiety, namely punicatannins A (1) and B (2), were isolated from pomegranate (Punica granatum) flowers. Their structures with absolute configuration were determined by detailed analysis of spectroscopic data, electronic circular dichroism (ECD) calculation, and chemical hydrolysis. A plausible biogenetic route involving a key enzymatic 1,4-Michael addition is proposed. Punicatannin A showed potent inhibition of α-glucosidase and lipogenic gene expression.

Three new hydrolyzable tannins including two gallotannins, jamutannins A (1) and B (2), and an ellagitannin, iso-oenothein C (3), along with eight known phenolic compounds were isolated from the seeds of Eugenia jambolana fruit. The structures were elucidated on the basis of spectroscopic data analysis. All compounds isolated were evaluated for α-glucosidase inhibitory effects compared to the clinical drug acarbose.

The antiproliferative effects of Canadian maple syrup (grades C and D) extracts and fifty-one purified phenolic constituents were evaluated against human tumourigenic (HT-29, HCT-116, and CaCo-2) and non-tumourigenic (CCD-18Co) colon cells. Overall, maple syrup ethyl acetate (MS-EtOAc), butanol (MS-BuOH), and methanol (MS-MeOH) extracts were more active against the tumourigenic versus non-tumourigenic colon cells. At equivalent phenolic levels, the antiproliferative activities of grade D > C maple syrup, and MS-BuOH > MS-MeOH > MS-EtOAc. Among the isolates, gallic acid, catechaldehyde, syringaldehyde, and catechol were most active and their higher levels in grade D MS-BuOH extract could account for the highest observed anticancer effects of that extract. Moreover, the maple syrup extracts did not induce apoptosis of the colon cancer cells but induced cell cycle arrest which was also associated with a decrease in cyclins A and D1 levels. These results suggest that phenolics may impart potential biological effects to maple syrup.Highlights► Maple syrup phenolic-enriched extracts were prepared and 50 phenolics isolated. ► Extracts and compounds inhibited growth of colon cancer more than normal colon cells. ► Antiproliferative effects were mediated through cell cycle arrest.

The red raspberry (Rubus idaeus) fruit contains bioactive polyphenols including anthocyanins and ellagitannins with reported anti-inflammatory properties. This study sought to investigate the cartilage-protecting and anti-inflammatory effects of a polyphenolic-enriched red raspberry extract (RRE; standardized to total polyphenol, anthocyanin, and ellagitannin contents) using (1) an in vitro bovine nasal explant cell culture model and (2) an in vivo adjuvant-induced arthritis rat model. RRE contained 20% total polyphenols (as gallic acid equivalents), 5% anthocyanins (as cyanidin-3-glucoside equivalents), and 9.25% ellagitannins (as ellagic acid equivalents). In the in vitro studies, bovine nasal explants were stimulated with 10 ng/mL IL-1β to induce the release of proteoglycan and type II collagen. On treatment with RRE (50 μg/mL), there was a decrease in the rate of degradation of both proteoglycan and type II collagen. In the in vivo antigen-induced arthritis rat model, animals were gavaged daily with RRE (at doses of 30 and 120 mg/kg, respectively) for 30 days after adjuvant injection (750 μg of Mycobacterium tuberculosis suspension in squalene). At the higher dose, animals treated with RRE had a lower incidence and severity of arthritis compared to control animals. Also, histological analyses revealed significant inhibition of inflammation, pannus formation, cartilage damage, and bone resorption by RRE. This study suggests that red raspberry polyphenols may afford cartilage protection and/or modulate the onset and severity of arthritis.

The cluster of papers included here is taken from research presentations at the most recent Berry Health Benefits Symposium (BHBS). The BHBS is a biennial conference that was initiated in 2005 and met for the fourth time in 2011. Similar to the past three meetings, the 2011 BHBS covers emerging and adds to the growing body of scientific knowledge supporting the positive effects of berry fruit on human health promotion and disease prevention. Important aspects of the BHBS also include fostering open communication and collaboration among several disparate groups necessary to ensure regular and continued consumption of berry fruits among the population. These groups include berry growers, producers, and processors, as well as basic and clinical researchers, media representatives, and health professionals. Thus, the BHBS continues to be an excellent forum for presenting and disseminating new and ongoing berry health benefits research.

Graphical abstractHighlights► Fourteen phenolics were isolated from the red maple (Acer rubrum) species. ► Ten of these compounds are being reported from A. rubrum for the first time. ► Five of these compounds are being reported from the Aceraceae family for the first time. ► First report of A-type linkage procyanidins and a chalcone from the Aceraceae family.

Red and sugar maple leaves collected in the summer and fall from Canada, were evaluated for phenolic content, antioxidant, α-glucosidase, and α-amylase inhibitory activities variation. The phenolic contents of summer red maple leaves (RML-S) and summer sugar maple leaves (SML-S) were higher than red and sugar maple leaves collected in fall (RML-F and SML-F, respectively). HPLC analyses showed differences in phenolic compounds present in the SML samples compared to the RML samples. The extracts were assayed for yeast and rat α-glucosidase inhibitory activities. Both results showed that SML-S extracts had the highest inhibitory activity which could possibly be attributed to the unique phenolics present therein. Milder effects were observed in terms of α-amylase inhibitory activity, with RML-F having the highest inhibitory activity. These results suggest that maple tree leaf extracts may have potential for phenolic-mediated α-glucosidase inhibition, relevant to type 2 diabetes management, with SML-S extract having the highest bioactivity.

Phenolic-enriched extracts of Canadian maple syrup, namely ethyl acetate (MS-EtOAc) and butanol (MS-BuOH), were evaluated for their ability to inhibit carbohydrate hydrolyzing enzymes relevant to type 2 diabetes management. Extracts were standardized to phenolic contents by the Folin–Ciocalteau method and assayed for yeast α-glucosidase inhibitory activities. On normalization to phenolic content, MS-BuOH exhibited higher inhibitory activity than MS-EtOAc (IC50 = 68.38 and 107.9 μg phenolics, respectively). The extracts were further assayed for inhibition of porcine α-amylase and rat α-glucosidase enzymes. MS-BuOH exhibited higher rat α-glucosidase and porcine α-amylase inhibitory activities (IC50 = 135 and 103 μg phenolics, respectively) than MS-EtOAC extract (IC50 > 187 μg phenolics in both assays). These results suggest that maple syrup extracts may have potential for phenolic-mediated type 2 diabetes management, with the MS-BuOH phenolic-enriched fraction having highest bioactivity.Highlights► Phenolic-enriched extracts, namely ethyl acetate and butanol, were prepared from pure maple syrup. ► Both extracts showed inhibitory effects against carbohydrate hydrolyzing enzymes relevant to type-2 diabetes management. ► Butanol extract was more active than the ethyl acetate extract.

The province of Quebec in Canada leads the world’s production of maple syrup, a natural sweetener obtained by thermal evaporation of sap collected from maple (Acer) species. As part of our laboratory’s detailed chemical investigation of Canadian maple syrup, a novel phenolic compound, 2,3,3-tri-(3-methoxy-4-hydroxyphenyl)-1-propanol, assigned the common name of quebecol, was obtained. Quebecol was isolated using a combination of chromatographic methods and identified by detailed 1D and 2D nuclear magnetic resonance (NMR) and mass spectral (MS) analyses. Liquid chromatography mass spectral (LC-MS) analyses revealed that quebecol is not originally present in maple sap. This observation, as well as the lack of a feasible biosynthetic pathway to explain its origin, suggests that quebecol is formed during the processing and/or extraction of maple syrup. Thus, the identification and biological evaluation of non-natural, process-derived compounds in maple syrup are warranted since such molecules may contribute towards the biological activities reported for this natural sweetener.Highlights► A novel phenolic compound isolated from maple syrup from Canada. ► Structure elucidated by extensive 1D and 2D NMR and MS data. ► Compound is non-natural process-derived phenolic.

Four new phenolic glycosides, saccharumosides A–D (1–4), along with eight known phenolic glycosides, were isolated from the bark of sugar maple (Acer saccharum). The structures of 1–4 were elucidated on the basis of spectroscopic data analysis. All compounds isolated were evaluated for cytotoxicity effects against human colon tumorigenic (HCT-116 and Caco-2) and nontumorigenic (CCD-18Co) cell lines.

Twenty-three phenolic compounds were isolated from a butanol extract of Canadian maple syrup (MS-BuOH) using chromatographic methods. The compounds were identified from their nuclear magnetic resonance and mass spectral data as 7 lignans [lyoniresinol (1), secoisolariciresinol (2), dehydroconiferyl alcohol (3), 5′-methoxy-dehydroconiferyl alcohol (4), erythro-guaiacylglycerol-β-O-4′-coniferyl alcohol (5), erythro-guaiacylglycerol-β-O-4′-dihydroconiferyl alcohol (6), and [3-[4-[(6-deoxy-α-l-mannopyranosyl)oxy]-3-methoxyphenyl]methyl]-5-(3,4-dimethoxyphenyl)dihydro-3-hydroxy-4-(hydroxymethyl)-2(3H)-furanone (7)], 2 coumarins [scopoletin (8) and fraxetin (9)], a stilbene [(E)-3,3′-dimethoxy-4,4′-dihydroxystilbene (10)], and 13 phenolic derivatives [2-hydroxy-3′,4′-dihydroxyacetophenone (11), 1-(2,3,4-trihydroxy-5-methylphenyl)ethanone (12), 2,4,5-trihydroxyacetophenone (13), catechaldehyde (14), vanillin (15), syringaldehyde (16), gallic acid (17), trimethyl gallic acid methyl ester (18), syringic acid (19), syringenin (20), (E)-coniferol (21), C-veratroylglycol (22), and catechol (23)]. The antioxidant activities of MS-BuOH (IC50 > 1000 μg/mL), pure compounds, vitamin C (IC50 = 58 μM), and a synthetic commercial antioxidant, butylated hydroxytoluene (IC50 = 2651 μM), were evaluated in the diphenylpicrylhydrazyl (DPPH) radical scavenging assay. Among the isolates, the phenolic derivatives and coumarins showed superior antioxidant activity (IC50 < 100 μM) compared to the lignans and stilbene (IC50 > 100 μM). Also, this is the first report of 16 of these 23 phenolics, that is, compounds 1, 2, 4−14, 18, 20, and 22, in maple syrup.

•Twenty-three medicinal plant extracts were evaluated for neuroprotective effects.•A neuroprotective potential algorithm (NPA) was developed.•Top candidates show neuroprotective effects in vitro and in Caenorhabditis elegans.•Top candidates have published animal data to support their neuroprotective effects.•NPA may be used to aid in selecting botanicals for further in vivo studies.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 (Aβ) 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-Aβ 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 Aβ1-42 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.Download full-size image