Polyphenol contents and radical scavenging capacities of red maple (Acer rubrum L.) extracts

Unveiling the Potential of Polyphenols as Anti-Amyloid Molecules in Alzheimer's Disease

Alzheimer's disease (AD) is a devastating neurodegenerative disease that mostly affects the elderly population. Mechanisms underlying AD pathogenesis are yet to be fully revealed, but there are several hypotheses regarding AD. Even though free radicals and inflammation are likely to be linked with AD pathogenesis, still amyloid-beta (Aβ) cascade is the dominant hypothesis. According to the Aβ hypothesis, a progressive buildup of extracellular and intracellular Aβ aggregates has a significant contribution to the AD-linked neurodegeneration process. Since Aβ plays an important role in the etiology of AD, therefore Aβ-linked pathways are mainly targeted in order to develop potential AD therapies. Accumulation of Aβ plaques in the brains of AD individuals is an important hallmark of AD. These plaques are mainly composed of Aβ (a peptide of 39-42 amino acids) aggregates produced via the proteolytic cleavage of the amyloid precursor protein. Numerous studies have demonstrated that various polyphenols (PPHs), including cyanidins, anthocyanins, curcumin, catechins and their gallate esters were found to markedly suppress Aβ aggregation and prevent the formation of Aβ oligomers and toxicity, which is further suggesting that these PPHs might be regarded as effective therapeutic agents for the AD treatment. This review summarizes the roles of Aβ in AD pathogenesis, the Aβ aggregation pathway, types of PPHs, and distribution of PPHs in dietary sources. Furthermore, we have predominantly focused on the potential of food-derived PPHs as putative anti-amyloid drugs.

Comparison of Antioxidant Properties and Metabolite Profiling of Acer pseudoplatanus Leaves of Different Colors

Acer pseudoplatanus (maple) is a widely grown ornamental plant. In addition to its ornamental and ecological value, it also has potentially high economic value. It is a rich source of polyphenols and exhibits antioxidant activity. However, the relationship between polyphenol content and antioxidant activity in maple leaves of different colors (green, yellow, and red) has not yet been investigated. In this study, the total polyphenol (TP), total flavonoid (TFlav), tannin (TET), chlorophyll a and b (Chl a and b), total anthocyanin (TAN), and total carotene (TAC) contents in maple leaves of different colors were evaluated. Their antioxidant activities were determined based on the inhibition of lipid oxidation, DPPH scavenging, ferric ion-reducing antioxidant power, and iron-chelating abilities. The concentrations of TP, TET, TFlav, TAN, and TAC in red maple leaves were higher than those in green and yellow maple leaves. In addition, red maple leaves showed a higher antioxidant effect than the leaves of the other two colors. We observed that antioxidant activity was positively correlated with TP, TFlav, and TAN and negatively correlated with Chl a and b. Finally, we analyzed the metabolites of the different colored (i.e., green, yellow, and red) maple leaves using gas chromatography/mass spectrometry (GC/MS) and found that the metabolite profile significantly varied between the different colors. These results suggest that red leaves are a good source of polyphenols and antioxidants and have potential use in the development of functional foods and medicinal applications.

Effects of Solid-State Fermentation Pretreatment with Single or Dual Culture White Rot Fungi on White Tea Residue Nutrients and In Vitro Rumen Fermentation Parameters

Fermentation of agricultural by-products by white rot fungi is a research hotspot in the development of ruminant feed resources. The aim of this study was to investigate the potential of the nutritional value and rumen fermentation properties of white tea residue fermented at different times, using single and dual culture white rot fungal species. Phanerochaete chrysosporium, Pleurotus ostreatus, and Phanerochaete chrysosporium + Pleurotus ostreatus (dual culture) solid-state fermented white tea residue was used for 4 weeks, respectively. The crude protein content increased significantly in all treatment groups after 4 weeks. Total extractable tannin content was significantly decreased in all treatment groups (p < 0.01). P. chrysosporium and dual culture significantly reduced lignin content at 1 week. The content of NH3-N increased in each treatment group (p < 0.05). P. chrysosporium treatment can reduce the ratio of acetic to propionic and improve digestibility. Solid state fermentation of white tea residue for 1 week using P. chrysosporium was the most desirable.

Extractable and Non-Extractable Antioxidants Composition in the eBASIS Database: A Key Tool for Dietary Assessment in Human Health and Disease Research

The antioxidant properties of foods are crucial in nutrition, food chemistry, and medicine studies but are often underestimated, with significant amounts of bioactive compounds containing physiological and biochemical properties remaining in the residue from extraction as non-extractable antioxidants. Over the last decade, extractable and non-extractable compounds have become key in the evaluation/determination of the antioxidant properties of food matrices because of their relevance in human health. This has led to the need to include extractable and non-extractable antioxidants in comprehensive and harmonized food composition databases for a wide range of applications within research, food, pharmaceutical, nutraceutical, and cosmeceutical areas. Additionally, the databases are invaluable as part of the health claims application process. eBASIS, (Bioactive Substances in Food Information System) a comprehensive database containing quality-evaluated scientific data, covering the composition of bioactive compounds present in foods, has flexible structures, allowing it to be extended to include newly emerging data on extractable and non-extractable compounds. Search criteria were developed and defined for compiling suitable peer-reviewed literature. Data quality assessment methods were established for the addition of composition data and antioxidant activity, with a focus on various parameters including: the extraction procedure, the antioxidant measurements, the expression of results. A total of 437 quality-evaluated datapoints on the composition of extractable and/or non-extractable compounds were entered into the database. This database update represents one of the first examples of building a database dedicated to antioxidant properties. This expansion of eBASIS provides a novel and unique tool for nutritionists, dietitians, researchers to use for a wide range of applications, such as dietary assessment, exposure studies and epidemiological studies, and may contribute to an increase in high-bioactive food consumption by consumers.

Screening of Antioxidant Potentials and Bioactive Properties of the Extracts Obtained from Two Centaurea L. Species (C. kroumirensis Coss. and C. sicula L. subsp sicula)

Herbal medicines, dietary supplements, or infusions with health promoting effects can note strong consumer demand. Hence, researchers and scientists have been increasingly focusing on the promotion of medicinal plants. In this respect, the present study has the evaluation of the biological properties of different extracts (hexane, chloroform, methanol, ultrasonic, essential oil, and supercritical) obtained from two Centaurea species (C. kroumirensis (Coss.) and C. sicula L. subsp sicula) as purpose. Antioxidative activities were assessed by in vitro assays including total phenolic content, free radical scavenging assay and ferric ion reducing power. Among the fourteen extracts examined, the highest total phenolic content (TPC) and antioxidant abilities were recorded in ultrasonic ethanol extracts of both Centaurea species. Additionally, these extracts exhibited a noticeable strong protective effect of the human skin fibroblast cell line (HS-68) that was exposed to oxidative stress induced by hydrogen peroxide. According to our results, the sonication with ethanol might be an ideal, rapid, and eco-friendly extraction method for obtaining a polyphenol-rich extract that exhibited high antioxidant activity. The results presented herein suggest that Centaurea species could be promoted as an antioxidant resource that could be exploited for the development of nutraceuticals or in pharmacology industry.

Defining a standardized methodology for the determination of the antioxidant capacity: case study of Pistacia atlantica leaves

Antioxidant activity can be measured by a variety of methods, that include hydrogen atom transfer (HAT) and single electron transfer (ET) methods.

Synthesis and Comparative Structure-Activity Study of Carbohydrate-Based Phenolic Compounds as α-Glucosidase Inhibitors and Antioxidants

Twenty-one natural and unnatural phenolic compounds containing a carbohydrate moiety were synthesized and their structure-activity relationship (SAR) was evaluated for α-glucosidase inhibition and antioxidative activity. Varying the position of the galloyl unit on the 1,5-anhydro-d-glucitol (1,5-AG) core resulted in changes in the α-glucosidase inhibitory activity and notably, particularly strong activity was demonstrated when the galloyl unit was present at the C-2 position. Furthermore, increasing the number of the galloyl units significantly affected the α-glucosidase inhibition, and 2,3,4,6-tetra-galloyl-1,5-AG (54) and 2,3,4,6-tetra-galloyl-d-glucopyranose (61) exhibited excellent activities, which were more than 13-fold higher than the α-glucosidase inhibitory activity of acertannin (37). Moreover, a comparative structure-activity study suggested that a hemiacetal hydroxyl functionality in the carbohydrate core and a biaryl bond of the 4,6-O-hexahydroxydiphenoyl (HHDP) group, which are components of ellagitannins including tellimagrandin I, are not necessary for the α-glucosidase inhibitory activity. Lastly, the antioxidant activity increased proportionally with the number of galloyl units.

Curcumin-Loaded Nanocapsules Reverses the Depressant-Like Behavior and Oxidative Stress Induced by β-Amyloid in Mice

Alzheimer's disease (AD) is a neurodegenerative disorder classically characterized by cognitive functions impairment. However, its symptomatology is complex and the depression is one of the most frequent behavioral changes in AD. AD pathology includes neuroinflammation and oxidative stress resulting in the Aβ protein accumulation. Curcumin is a natural phenolic compound that shows antioxidant and anti-inflammatory properties. Nevertheless, therapeutic use of curcumin is limited due to its low bioavailability and biodistribution. In this context, the use of curcumin-loaded nanocapsules (NLC C) emerges to overcome its limitations. Thus, the present study investigated the effects of NLC C on the depressant-like behavior and oxidative stress induced by an animal model of AD. For this, Swiss male mice were divided into five groups. The Aβ, Aβ + NLC C and Aβ + Curcumin groups received Aβ_25-35 aggregate (3 nmol/3 μL, i.c.v.). Control and NLC C groups received only vehicle. The NLC C were administered via gavage at a dose of 10 mg/kg in alternate days for 12 days. Our results demonstrated that Aβ infusion induced a depressantant-like behavior observed in the tail suspension and forced swimming tests, which was reversed by NLC C treatment. No change was observed in mice locomotion. Furthermore, NLC C reduced the Aβ-generated oxidative stress in the prefrontal cortex, evidenced by the increase in the reactive species levels, superoxide dismutase and catalase activities. Importantly, NLC C were more effective than the free curcumin. Thus, we demonstrated the antidepressant-like and antioxidant effects of NLC C in a mouse model of AD, suggesting its therapeutic potential for this disorder.

Polyphenols Modulate Alzheimer's Amyloid Beta Aggregation in a Structure-Dependent Manner

Some polyphenols, which are common natural compounds in fruits, vegetables, seeds, and oils, have been considered as potent inhibitors of amyloid beta (Aβ) aggregation, one critical pathogenic event in Alzheimer’s disease (AD). However, the mechanisms by which polyphenols affect aggregation are not fully understood. In this study, we aimed to investigate the effect of two classes of polyphenols (flavonoids and stilbenes) on the self-assembly of Aβ_42, in particular, how this relates to structure. We found that the flavonoids gallocatechin gallate (GCG) and theaflavin (TF) could completely inhibit Aβ aggregation, while two stilbenes, resveratrol and its glucoside derivative piceid, could also suppress Aβ aggregation, but to a much lesser extent. Intriguingly, resveratrol accelerated the formation of Aβ fibrils before its decreasing effect on fibrillation was detected. Atomic force microscopy (AFM) images showed a huge mass of long and thin Aβ fibrils formed in the presence of resveratrol. Although the morphology was the same in the presence of piceid, the fibrils were sparse in the presence of picead. In the presence of flavonoids, Aβ morphology was unchanged from prior to incubation (0 h), in agreement with amyloid beta kinetics analysis using thioflavin-T fluorescence assay. The electrochemical data showed a higher ability of GCG and TF to interact with Aβ than resveratrol and piceid, which could be attributed to the presence of more aromatic rings and hydroxyl groups. In addition, the two flavonoids exhibited a similar propensity for Aβ aggregation, despite having some differences in their structure. However, in the case of stilbenes, the addition of a glucoside at C-7 slightly decreased anti-Aβ aggregation property compared to resveratrol. These findings contribute to a better understanding of the essential structural features of polyphenols required for inhibiting Aβ aggregation, and the possible mechanisms for modulating aggregation.

Influence of the in vitro gastrointestinal digestion on the antioxidant activity of Artemisia gorgonum Webb and Hyptis pectinata (L.) Poit. infusions from Cape Verde

The phenolic profile and antioxidant activity of Cape Verde's Artemisia gorgonum Webb and Hyptis pectinata (L.) Poit. infusions before and after in vitro simulation of the gastrointestinal digestion were determined. The LC-UV/DAD fingerprinting analysis allowed the identification of 3-O-caffeoylquinic acid, chlorogenic acid, 3,5 dicaffeoylquinic acid, 4,5-dicaffeoylquinic acid and other caffeoylquinic acids derivatives on A. gorgonum infusion, and of caffeoylquinic acid and quercetin derivatives on H. pectinata infusion. Despite some decrease in the chromatographic area of several peaks, no relevant qualitative alterations on the chromatographic profile were observed between the digested and undigested herbal infusions. Results obtained showed a decrease on the antioxidant capacity of both tested herbal infusions after the in vitro digestion. This decrease was more pronounced for H. pectinata than for A. gorgonum and was also more pronounced regarding the radical scavenging capacity than regarding the reducing capacity. After complete digestion the superoxide anion and the DPPH-radical scavenging capacities decreased ≈ 43 and 75% for H. pectinata and ≈ 31 and 70% for A. gorgonum. Despite the observed differences before and after simulated gastrointestinal digestion, both infusions still had antioxidant activity at the end of this process. Thus, the antioxidant potential of A. gorgonum and H. pectinata infusions from Cape Verde, prepared as traditionally used, seems to be kept in some extend throughout the digestive system.

Ultra-fast liquid chromatography coupled with electrospray ionization time-of-flight mass spectrometry for the rapid phenolic profiling of red maple (Acer rubrum) leaves

The red maple (Acer rubrum) species is economically important to North America because of its sap, which is used to produce maple syrup. In addition, various other red maple plant parts, including leaves, were used as a traditional medicine by the Native Americans. Currently, red maple leaves are being used for nutraceutical and cosmetic applications but there are no published analytical methods for comprehensive phytochemical characterization of this material. Herein, a rapid and sensitive method using liquid chromatography with electrospray ionization time-of-flight tandem mass spectrometry was developed to characterize the phenolics in a methanol extract of red maple leaves and a proprietary phenolic-enriched red maple leaves extract (Maplifa™). Time-of-flight mass spectrometry and tandem mass spectrometry experiments led to the identification of 106 phenolic compounds in red maples leaves with the vast majority of these compounds also detected in Maplifa™. The compounds included 68 gallotannins, 25 flavonoids, gallic acid, quinic acid, catechin, epicatechin, and nine other gallic acid derivatives among which 11 are potentially new and 75 are being reported from red maple for the first time. The developed method to characterize red maple leaves phenolics is rapid and highly sensitive and could aid in future standardization and quality control of this botanical ingredient.

Nutrients, Antioxidant Capacity and Safety of Hot Water Extract from Sugar Maple (Acer saccharum M.) and Red Maple (Acer rubrum L.) Bark

Sugar maple (Acer saccharum M.) and red maple (Acer rubrum L.) barks were treated with hot water to extract nutrients in order to explore, for the first time, its potential as safe dietary antioxidants. The organic and inorganic nutrients of these extracts, as well as their safety on human PLB-985 cells differentiated into neutrophils-like cells, were determined. Proximate analysis showed that both bark extracts were low in moisture and fat. Sugar maple bark extract (SM-BX) showed crude protein and ash content higher than those found in red maple bark extract (RM-BX). In addition, SM-BX had total sugars higher than those evaluated in RM-BX, while complex sugars (oligo- and/or poly-saccharides) were similarly abundant in both bark extracts. Furthermore, SM-BX demonstrated a wide array of vital minerals (K, Ca, Mg, P, Na, Fe and Cu) in quantity larger than that evaluated in RM-BX, whereas RM-BX have Zn and Mn levels higher than those found in SM-BX. Phytochemical analyses showed that RM-BX exhibited total phenolic and flavonoid contents higher than those measured in SM-BX. Consequently, RM-BX presented an antioxidant activity higher than that of SM-BX: 2.85-fold ABTS radical cation scavenging capacity and 1.9-fold oxygen radical absorbance capacity. Finally, RM-BX and SM-BX were greatly safe since, at concentration up to 100 μg/ml, they did not modify the viability of neutrophils as determined by flow-cytometry assay using Annexin V-FITC/Propidum Iodide as markers. In conclusion, our in vitro studies indicate that both red and sugar maple bark extracts have a real potential as food additives.

Inhibition of collagenase and melanogenesis by ethanol extracts of Orostachys japonicus A. Berger: possible involvement of Erk and Akt signaling pathways in melanoma cells

Orostachys japonicus is an herb that contains several functional components and has traditionally been used to treat various diseases in Asia. In this study, bioactive components from different parts of the O. japonicus plant were investigated, and the contents of the functional components in ethanol extracts of O. japonicus cultivated in Korea and China were compared. The antioxidant effects of O. japonicus ethanol extracts were investigated using Raw 264.7 cells. It was found that 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity was significantly decreased in the cells treated with the extracts. Moreover, the novel inhibitory functions of O. japonicus extracts on collagenase, elastase, and tyrosinase were established. We also found that O. japonicus extracts strongly inhibited melanin synthesis in B16F10 melanoma cells by decreasing MITF protein levels and activating the Erk and Akt signaling pathways. Thus, these findings would be useful for developing new cosmetic and pharmaceutical formulations based on O. japonicus extracts.

Transformation of Sugar Maple Bark through Catalytic Organosolv Pulping

The catalytic organosolv pulping of sugar maple bark was performed adopting the concept of forest biorefinery in order to transform bark into several valuable products. Our organosolv process, consisting of pre-extracting the lignocellulosic material followed by pulping with ferric chloride as a catalyst, was applied to sugar maple bark. The pre-extraction step has yielded a mixture of phenolic extractives, applicable as antioxidants. The organosolv pulping of extractives-free sugar maple bark yielded a solid cellulosic pulp (42.3%) and a black liquor containing solubilized bark lignin (24.1%) and products of sugars transformation (22.9% of hemicelluloses), mainly represented by furfural (0.35%) and 5-hydroxymethyl furfural (HMF, 0.74%). The bark cellulosic pulp was determined to be mainly constituted of glucose, with a high residual lignin content, probably related to the protein content of the original bark (containing cambium tissue). The biorefinery approach to the transformation of a solid bark residue into valuable biopolymers (lignin and cellulose) along with phenolic antioxidants from pre-extraction and the HMF derivatives from black liquor (applicable for 2,5-diformylfuran production) is an example of a catalytic process reposing on sustainable engineering and green chemistry concepts.

Fruit Peel Polyphenolic Extract-Induced Apoptosis in Human Breast Cancer Cells Is Associated with ROS Production and Modulation of p38MAPK/Erk1/2 and the Akt Signaling Pathway

Polyphenols represent a large group of natural substances with different biological properties. Currently, polyphenols are well studied due to their free radicals' scavenging and antioxidant activities. However, some studies indicate that polyphenols also exhibit pro-oxidant properties. In this study, the possible involvement of the pro-oxidant activities of fruit polyphenols was investigated in relation to apoptosis induction. To determine the type of cell death induced by fruit polyphenols (Flavine; F7), we assessed a series of assays, including measurements of caspase-7 activation, membrane mitochondrial potential changes, reactive oxygen (ROS) and nitrogen species production, lipid peroxidation, antioxidant enzymes activities, and PARP cleavage. Moreover, the effect of F7 on selected pro- and antisurvival signaling pathways was determined. We demonstrated that fruit polyphenols induced caspase-dependent cell death associated with increased oxidative stress. We also showed fruit polyphenol-mediated release of mitochondrial pro- and antiapoptotic proteins of the Bcl-2 family and modulation activity of the Akt, p38 MAPK, and Erk 1/2 pathways as well as the signaling of ROS-mediated DNA damage. Our data demonstrated that fruit peel polyphenols suppressed breast cancer cell growth through increased intracellular oxidative stress and the activation of p38 MAPK and de-activation of the Erk 1/2 and Akt signaling pathways.

Screening and evaluation of active compounds in polyphenol mixtures by HPLC coupled with chemical methodology and its application

An off-line high performance liquid chromatography (HPLC) coupled with chemical methods has been developed to evaluate antioxidant activity of 11 standard polyphenol compounds (SPCs) and vitamin C (Vc) in terms of radical scavenging abilities. The structure-activity relationships of each SPC were also discussed. SPCs showed different abilities in scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis-3-ethyl-benzthiazoline-6-sulphonate (ABTS+) and hydroxyl (OH) free radicals. Among SPCs, quercetin and kaempferol, as typical flavonoids, displayed the greatest radical-scavenging activities and even exhibited higher activity in OH radical removal ability than that of Vc. Furthermore, the proposed method was also applied to screening polyphenolic antioxidant components from Cichorium endivia L. (C. endivia) seed extract. The results indicated that cynarin in the extract was a more active compound to scavenge DPPH and ABTS+ radicals than chlorogenic acid, while chlorogenic acid had stronger capacity in scavenging OH free radicals.

Comparison of phenolic components and biological activities of two Centaurea sp. obtained by three extraction techniques

OBJECTIVE

The present study aimed to compare the polyphenol content, total phenolic, total flavonoid, antioxidant and antimicrobial activity of the extracts obtained from Centaurea amaena Boiss. & Balansa and Centaurea aksoyi Hamzaoğlu & Budak.

METHODS

Both species were subjected to maceration, Soxhlet and ultrasonication extractions with methanol in order to macerated (ME), Soxhlet (SE) and ultrasonicated (UE) extracts. Their phenolic profiles were qualitatively examined by LC-MS. Their antioxidant activities were determined by phosphomolybdenum, β-carotene bleaching and DPPH assays. Agar diffusion and broth dilution methods were carried out to find the antimicrobial activity of these extracts against fifteen microorganisms.

RESULTS

Quercetin, quercetin-3-β-D-glucoside and protocatechuic acid were the main components of the both extracts obtained by Soxhlet extraction. The highest phenolic and flavonoid contents were found in the UE for both species. All the extracts exhibited good total antioxidant and DPPH radical scavenging activity. UE obtained from C. amaena showed the highest antioxidant activity with the highest phenolic and flavonoid contents. The antibacterial activity of UE obtained from C. amaena was better than other extracts and antibacterial activity of C. amaena was also better than C. aksoyi.

DISCUSSION

This study confirms that ultrasonic extraction may be an ideal, simple and rapid method to obtain polyphenol-rich extracts have antioxidant as well as antibacterial activity from both Centaurea species especially from C. amaena.

Antioxidant Capacity, Phenolic Constituents and Toxicity of Hot Water Extract from Red Maple Buds

The present study reports, for the first time, the results of the antioxidant capacity and the phenolic composition of a hot water extract from red maple buds (RMB), as well as its safety. In this regard and comparatively to antioxidant standards, this extract exhibits a significant antiradical capacity when tested by 2,2-diphenyl-1-picrylhydrazyl (DPPH^· ) and anion superoxide trapping assays. High-resolution mass spectrometric and nuclear magnetic resonance analyses permitted to determine for the first time, in red maple species, cyanidin-3-O-glucoside, quercetin-3-O-galactoside, quercetin-3-O-arabinoside, and quercetin. Also, the quantification of individual phenolics by high-performance liquid chromatography method revealed that ginnalin A at 117.0 mg/g is the major compound of RMB hot water extract. Finally, using flow cytometry evaluation, the extract of RMB was determined to have no toxicity neither to cause significant modification of apoptosis process, up to concentration of 100 μg/ml, on human peripheral blood neutrophils. These results allow anticipating various fields of application of RMB water extract.

Methanol leaf extract of Actinodaphne sesquipedalis (Lauraceae) enhances gastric defense against ethanol-induced ulcer in rats

Actinodaphne sesquipedalis Hook. F. Var. Glabra (Kochummen), also known as “Medang payung” by the Malay people, belongs to the Lauraceae family. In this study, methanol leaf extract of A. sesquipedalis was investigated for their acute toxicity and gastroprotective effects to reduce ulcers in rat stomachs induced by ethanol. The rats were assigned to one of five groups: normal group (group 1), ulcer group (group 2), control positive drug group (group 3) and two experimental groups treated with 150 mg/kg (group 4) and 300 mg/kg (group 5) of leaf extract. The rats were sacrificed an hour after pretreatment with extracts, and their stomach homogenates and tissues were collected for further evaluation. Macroscopic and histological analyses showed that gastric ulcers in rats pretreated with the extract were significantly reduced to an extent that it allowed leukocytes penetration of the gastric walls compared with the ulcer group. In addition, an ulcer inhibition rate of >70% was detected in rats treated with both doses of A. sesquipedalis extract, showing a notable protection of gastric layer. Severe destruction of gastric mucosa was prevented with a high production of mucus and pH gastric contents in both omeprazole-treated and extract-treated groups. Meanwhile, an increase in glycoprotein uptake was observed in pretreated rats through accumulation of magenta color in Periodic Acid Schiff staining assay. Analysis of gastric homogenate from pretreated rats showed a reduction of malondialdehyde and elevation of nitric oxide, glutathione, prostaglandin E2, superoxide dismutase and protein concentration levels in comparison with group 2. Suppression of apoptosis in gastric tissues by upregulation of Hsp70 protein and downregulation of Bax protein was also observed in rats pretreated with extract. Consistent results of a reduction of gastric ulcer and the protection of gastric wall were obtained for rats pretreated with A. sesquipedalis extract, which showed its prominent gastroprotective potential in rats’ stomach against ethanol-induced ulcer.

Study Approach of Antioxidant Properties in Foods: Update and Considerations

The assessment of interactions between natural antioxidants and other food matrix components represents the main step in the investigation of total antioxidant properties, in terms of potential health benefits. The diversity of chemical structures of natural compounds, besides their possible interactions, as well as the biological role and different modes of action makes it difficult to assess a single and reliable procedure for the evaluation of antioxidant activity. Today, much attention is given to the distinction between extractable and non-extractable antioxidants as a key tool in the description of the nutritional and healthy properties of food matrices. The starting point for the investigation of antioxidant effects of food extracts is the analysis of antioxidant properties of pure compounds and their interactions. Another complementary approach could be represented by the study of how different biologically active compound-rich extracts contribute to the total antioxidant capacity.

Traditional uses, phytochemistry, and pharmacology of the genus Acer (maple): A review

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Acer (Aceraceae), commonly known as maple, comprises approximately 129 species that primarily grow in the northern hemisphere, especially in the temperate regions of East Asia, eastern North America, and Europe. These plants have been traditionally used to treat a wide range of diseases in East Asia and North America. Moreover, clinical studies have shown that medicinal plants belonging to Acer are highly effective in the treatment of rheumatism, bruises, hepatic disorders, eye disease, and pain, and in detoxification. This review provides a systematic and constructive overview of the traditional uses, chemical constituents, and pharmacological activities of plants of the genus Acer.

MATERIAL AND METHODS

This review is based on a literature study of scientific journals and books from libraries and electronic sources such as SciFinder, ScienceDirect, Springer, PubMed, CNKI, Google Scholar, Baidu Scholar, and Web of Science. The literature in this review related to chemical constituents and pharmacological activities dates from 1922 to the end of October 2015. Furthermore, ethnopharmacological information on this genus was obtained from libraries and herbaria in China and USA.

RESULTS

In traditional medicine, 40 species, 11 subspecies, and one varieta of the genus Acer are known to exhibit a broad spectrum of biological activities. To date, 331 compounds have been identified from 34 species of the genus Acer, including flavonoids, tannins, phenylpropanoids, diarylheptanoids, terpenoids, benzoic acid derivatives, and several other types of compounds, such as phenylethanoid glycosides and alkaloids. Preliminary pharmacological studies have shown that the extracts and compounds isolated from this genus exhibit a broad spectrum of biological activities such as antioxidant, antitumor, anti-inflammatory, antidiabetic, hepatoprotective, and antiobesity activities, as well as promoting osteoblast differentiation. To date, reports on the toxicity of Acer species to humans are very limited, and the major safety concern of these plants is in the veterinary field.

CONCLUSIONS

Based on our systematic review, Acer species can be used to treat rheumatism, hepatic disorders, eye disease, pain, etc. effectively. Some indications from ethnomedicine have been validated by pharmacological activities, such as the anti-inflammatory and hepatoprotective activities of the species. The available literature showed that most of the activities of these species can be attributed to flavonoids and tannins. To ensure the safety and efficacy in clinical practice in the future, studies identifying active molecules and clarifying their pharmacological mechanisms as well as toxicity are needed.

Phenol profiles and antioxidant capacities of Bistort Rhizoma (Polygonum bistorta L.) extracts

This work demonstrated that the crude Bistort Rhizoma (BR) extracts exhibit an antioxidant effectiveness, which significantly correlated with the content of TP, showing that TP may be responsible for the antioxidant activity of BR extract.

Red Maple (Acer Rubrum) Aerial Parts as a Source of Bioactive Phenolics

The bark and stems of red maple ( Acer rubrum) are reported to contain bioactive phenolics but its aerial parts, namely, flowers and leaves, remain largely unexplored. This is unfortunate considering that various parts of the red maple were used for traditional medicinal purposes by the indigenous peoples of eastern North America, where this species is found. Herein, we report the identification of twenty-five (1–25) phenolics, including two new galloyl derivatives (1 and 2), from red maple flowers and leaves. Of these, ten compounds (1–10), including the new compounds, were isolated and identified by NMR and HRESIMS data while the remaining fifteen compounds (11–25) were identified by HPLC-DAD analyses (by comparison with chemical standards). The isolates (1–10), along with the clinical drug, acarbose, were evaluated for their α-glucosidase enzyme inhibitory activities.

Study of Polyphenol Content and Antioxidant Capacity of Myrianthus Arboreus (Cecropiaceae) Root Bark Extracts

In order to evaluate the therapeutic potential of polyphenolic extracts from root bark of M. arboreus, we have determined the content of various polyphenols in aqueous and ethanol (EtOH) extract as well as two sub-fractions of the latter: ethyl acetate (EAc) and hexane (Hex). The total phenols, flavonoids, hydroxycinnamic acids and proanthocyanidins have been determined for all studied extracts/fractions by spectrophotometric methods. Both TP content (331.5 ± 2.5 mg GAE/g) and HCA content (201 ± 1.5 mg CAE/g) were determined to be the highest in EAc fraction of EtOH extract. All studied extracts were however determined to have a low content in flavonoids. The determination of antioxidant capacities of the studied extracts has also been performed by the following in vitro antioxidant tests: DPPH scavenging, phosphomolybdenum method and oxygen radical absorbance (ORACFl and ORACPRG) assay. The results of the DPPH free radical and ORACFl assays showed that there is no significant difference between the EAc fraction and Oligopin(®), but the EAc fraction exhibited the highest antioxidant capacity as determined by the phosphomolybdenium method. In addition, the EtOH extract was determined to have the same antioxidant efficiency as the synthetic antioxidant BHT or commercial extract Oligopin(®) by phosphomolybdenum method. On the other hand, a positive correlation (r < 0.6) was found between different classes of polyphenols and the results of the phosphomolybdenum method, ORACFl as well as ORACPRG, except for the DPPH assay, for which a negative correlation was indicated (r < 0.62). Interestingly, it seems that the content in hydroxycinnamic acids played a big role in all assays with r < 0.9. According to the present study, EAc fraction and EtOH extract should be further studied for the potential use in the pharmaceutical and food industry.

Biochanin a gastroprotective effects in ethanol-induced gastric mucosal ulceration in rats

BACKGROUND

Biochanin A notable bioactive compound which is found in so many traditional medicinal plant. In vivo study was conducted to assess the protective effect of biochanin A on the gastric wall of Spraguedawley rats` stomachs.

METHODOLOGY

The experimental set included different animal groups. Specifically, four groups with gastric mucosal lesions were receiving either a) Ulcer control group treated with absolute ethanol (5 ml/kg), b) 20 mg/kg of omeprazole as reference group, c) 25 of biochanin A, d) 50 mg/kg of biochanin A. Histopathological sectioning followed by immunohistochemistry staining were undertaken to evaluate the influence of the different treatments on gastric wall mucosal layer. The gastric secretions were collected in the form of homogenate and exposed to superoxide dismutase (SOD) and nitric oxide enzyme (NO) and the level of malondialdehyde (MDA) and protein content were measured. Ulceration and patchy haemorrhage were clearly observed by light microscopy. The morphology of the gastric wall as confirmed by immunohistochemistry and fluorescent microscopic observations, exhibited sever deformity with notable thickness, oedematous and complete loss of the mucosal coverage however the biochanin-pretreated animals, similar to the omeprazole-pretreated animals, showed less damage compared to the ulcer control group. Moreover, up-regulation of Hsp70 protein and down-regulation of Bax protein were detected in the biochanin A pre-treated groups and the gastric glandular mucosa was positively stained with Periodic Acid Schiff (PAS) staining and the Leucocytes infiltration was commonly seen. Biochanin A displayed a great increase in SOD and NO levels and decreased the release of MDA.

CONCLUSIONS

This gastroprotective effect of biochanin A could be attributed to the enhancement of cellular metabolic cycles perceived as an increase in the SOD, NO activity, and decrease in the level of MDA, and also decrease in level of Bax expression and increase the Hsp70 expression level.

Anti-ulcerogenic effect of methanolic extracts from Enicosanthellum pulchrum (King) Heusden against ethanol-induced acute gastric lesion in animal models

A natural source of medicine, Enicosanthellum pulchrum is a tropical plant which belongs to the family Annonaceae. In this study, methanol extract from the leaves and stems of this species was evaluated for its gastroprotective potential against mucosal lesions induced by ethanol in rats. Seven groups of rats were assigned, groups 1 and 2 were given Tween 20 (10% v/v) orally. Group 3 was administered omeprazole 20 mg/kg (10% Tween 20) whilst the remaining groups received the leaf and stem extracts at doses of 150 and 300 mg/kg, respectively. After an additional hour, the rats in groups 2-7 received ethanol (95% v/v; 8 mL/kg) orally while group 1 received Tween 20 (10% v/v) instead. Rats were sacrificed after 1 h and their stomachs subjected to further studies. Macroscopically and histologically, group 2 rats showed extremely severe disruption of the gastric mucosa compared to rats pre-treated with the E. pulchrum extracts based on the ulcer index, where remarkable protection was noticed. Meanwhile, a significant percentage of inhibition was shown with the stem extract at 62% (150 mg/kg) and 65% (300 mg/kg), whilst the percentage with the leaf extract at doses of 150 and 300 mg/kg was 63% and 75%, respectively. An increase in mucus content, nitric oxide, glutathione, prostaglandin E2, superoxide dismutase, protein and catalase, and a decrease in malondialdehyde level compared to group 2 were also obtained. Furthermore, immunohistochemical staining of groups 4-7 exhibited down-regulation of Bax and up-regulation of Hsp70 proteins. The methanol extract from the leaves and the stems showed notable gastroprotective potential against ethanol.

Polyphenols as therapeutic molecules in Alzheimer's disease through modulating amyloid pathways

Alzheimer's disease (AD) is a complex and multifactorial neurodegenerative condition. The complex pathology of this disease includes oxidative stress, metal deposition, formation of aggregates of amyloid and tau, enhanced immune responses, and disturbances in cholinesterase. Drugs targeted toward reduction of amyloidal load have been discovered, but there is no effective pharmacological treatment for combating the disease so far. Natural products have become an important avenue for drug discovery research. Polyphenols are natural products that have been shown to be effective in the modulation of the type of neurodegenerative changes seen in AD, suggesting a possible therapeutic role. The present review focuses on the chemistry of polyphenols and their role in modulating amyloid precursor protein (APP) processing. We also provide new hypotheses on how these therapeutic molecules may modulate APP processing, prevent Aβ aggregation, and favor disruption of preformed fibrils. Finally, the role of polyphenols in modulating Alzheimer's pathology is discussed.

Evaluation of antidiabetic and antioxidant properties of Brucea javanica seed

The ethanol extract of B. javanica seed was fractionated with solvents of different polarities and tested for antioxidant activities by several assays including DPPH radical scavenging activity, ferric reducing antioxidant power (FRAP), ferrous ion chelating activity (FCA), and nitric oxide radical scavenging activity (NORSA) along with their polyphenolic contents. Antidiabetic activity was evaluated both in vitro and in vivo using a glycogen phosphorylase α (GPα) inhibition assay and oral glucose tolerance test (OGTT) in nondiabetic rats. The ethyl acetate fraction (EAF), rich in tannin, exhibited the strongest antioxidant activities to DPPH, FRAP, and NORSA, except for FCA. The EAF also exerted a dose-depended inhibition of GPα (IC50 = 0.75 mg/ml). Further evaluation of hypoglycemic effect on OGGT indicated that rats treated with EAF (125 mg/kg bw) showed a 39.91% decrease (P < 0.05) in blood glucose levels at 30 min, and continuous fall (P < 0.05) of 28.89% and 20.29% was observed in the following hours (60 and 90 min) compared to the normal control during OGTT. The EAF was applied to polyamide column chromatography, and the resulting tannin-free fraction was tested for both GPα inhibition and antioxidant (DPPH only) activity. The GP α inhibitory activity was retained, while antioxidant activity was lost (4.6-fold) after tannin removal. These results concluded that the GPα inhibitory activity initially detected was primarily due to the compounds other than tannins, whereas antioxidant activity was mainly due to the tannins.

Maplexins, new α-glucosidase inhibitors from red maple (Acer rubrum) stems

Thirteen gallic acid derivatives including five new gallotannins, named maplexins A-E, were isolated from red maple (Acer rubrum) stems. The compounds were identified by spectral analyses. The maplexins varied in number and location of galloyl groups attached to 1,5-anhydro-d-glucitol. The isolates were evaluated for α-glucosidase inhibitory and antioxidant activities. Maplexin E, the first compound identified with three galloyl groups linked to three different positions of 1,5-anhydro-d-glucitol, was 20 fold more potent than the α-glucosidase inhibitory drug, Acarbose (IC(50)=8 vs 160 μM). Structure-activity related studies suggested that both number and position of galloyls attached to 1,5-anhydro-d-glucitol were important for α-glucosidase inhibition.