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New maplexin FI and phenolic glycosides from red maple (Acer rubrum) bark
... Therefore, this extract was chosen for further study. The present article reports the isolation and structural elucidation of three previously undescribed neolignan glycosides (1-3) and fourteen known compounds (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17) from the methanol extract of A. yunnanensis leaves and their NO production inhibitory effect in LPS-activated RAW264.7 cells. ...
... The known compounds were identified as urolignoside (4), [11] (7S,8R)-dihydrodehydrodiconiferyl alcohol (5), [4] (7S,8R)dihydrodehydrodiconiferyl alcohol 9-O-β-D-glucopyranoside (6) [11] cornuskoside A (7), [12] icariside E4 (8), [13] isodonoside VI (9), [7] rubrumodise A (10), [14] (threo)-1-(4-hydroxy-3-methoxyphenyl)-2-[4-(3-hydroxypropyl)-2-methoxyphenoxy]-1,3-propanediol (11), [14] (erythro)-1-(4-hydroxy-3-methoxyphenyl)-2-[4-(3-hydroxypropyl)-2-methoxyphenoxy]-1,3-propanediol (12), [15] pinobato (13), [16] matairesinol 4'-O-β-D-glucopyranoside (14), [17] pinoresinol (15), [18] lariciresinol 4'-O-β-D-glucopyranoside (16), [19] isorhamnetin 3-O-rutinoside (17) [20] by comparison of their NMR and CD data with those reported in the literature. ...
... The known compounds were identified as urolignoside (4), [11] (7S,8R)-dihydrodehydrodiconiferyl alcohol (5), [4] (7S,8R)dihydrodehydrodiconiferyl alcohol 9-O-β-D-glucopyranoside (6) [11] cornuskoside A (7), [12] icariside E4 (8), [13] isodonoside VI (9), [7] rubrumodise A (10), [14] (threo)-1-(4-hydroxy-3-methoxyphenyl)-2-[4-(3-hydroxypropyl)-2-methoxyphenoxy]-1,3-propanediol (11), [14] (erythro)-1-(4-hydroxy-3-methoxyphenyl)-2-[4-(3-hydroxypropyl)-2-methoxyphenoxy]-1,3-propanediol (12), [15] pinobato (13), [16] matairesinol 4'-O-β-D-glucopyranoside (14), [17] pinoresinol (15), [18] lariciresinol 4'-O-β-D-glucopyranoside (16), [19] isorhamnetin 3-O-rutinoside (17) [20] by comparison of their NMR and CD data with those reported in the literature. ...
Phytochemical study on the leaves of Amentotaxus yunnanensis led to the isolation of seventeen phenolic compounds including sixteen neolignans and lignans, and one flavone glycoside. Three among the isolates were previously unreported neolignans and named as amenyunnaosides A-C, respectively. Their structures were elucidated by extensive analyses of HR-ESI-MS, 1D and 2D NMR, and ECD spectra. The isolated neolignans potentially inhibited NO production in LPS-activated RAW264.7 cells with their IC50 values ranging from 11.05 to 44.07 μM, compared to that of the positive control compound, dexamethasone, IC50 value of 16.93 μM. Additionally, amenyunnaoside A dose-dependently reduced production of IL-6 and COX-2 but did not effect to that of TNF-α at concentrations of 0.8, 4, and 20 µM.
... Reference standards for maplexin A, maplexin B, maplexin C, maplexin D, ginnalin A, ginnalin B, ginnalin C, 3,6-di-O-galloyl-1,5-anhydroglucitol, catechin, epicatechin, gallic acid, gallic acid methyl ester, 5-methyl gallic acid methyl ester, and ellagic acid, used for ESI-TOF-MS/MS characterization, were previously isolated and identified by our laboratory [8,9,16]. LC-MS grades of acetonitrile and methanol were purchased from Sigma-Aldrich (St. Louis, MO, USA). ...
... Leaves of the red maple species were collected in the summer and botanically authenticated with a deposited voucher specimen as previously reported by our laboratory [8][9][10]. Finely powdered air-dried red maple leaves (1.0 g) was extracted by sonication with methanol (10 mL) for 1 hour under room temperature. ...
... These biological effects have largely been attributed to the phenolic constituents found in the red maple species, in particular, anhydro-1,5-glucitol-core containing gallotannins which are only produced by certain members of the maple (Acer) genus in the entire higher plant kingdom [7]. Our group has conducted extensive previous isolation and structure elucidation studies (by TOF-MS and NMR spectroscopic data) of the leaves, flowers, twigs, and barks of the red maple species which yielded a series of new compounds containing different numbers of galloyl substituents located at different positions on the anhydro-1,5-glucitol-core [8][9][10]. In addition, the buds of the red maple species have also been reported to contain a variety of phenolic sub-classes, including anhydro-1,5-glucitol-core containing gallotannins [3]. ...
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 9 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.
... Previous studies dealing with sugar maple and red maple bark extracts have highlighted the presence of many classes of polyphenols, such as gallic acid derivatives, ellagic acids, lignans and flavonoids. Phytochemical analysis pointed out the major polyphenols presented in maple bark are maplexins, which are gallotannins with a 1,5-anhydro-glucitol moiety [6]. Gallotannins belong to hydrolysable tannins, which are also listed as GRAS (generally recognized as safe) by Food and Drug Administration [7]. ...
... Maple bark extracts, mainly those from red maple, reportedly showed in vitro radical scavenging ability, hence a potent antioxidant [8]. In addition, phenolicrich bark extracts from sugar maple and red maple were demonstrated to have glucidase inhibitory and anticancer activities [6,9]. These abovementioned health beneficial activities of maple bark extracts were mainly credited to phenolic compounds found in them. ...
... Total Phytochemicals Maple bark is reported to contain a wide range of extractable phenolic compounds including gallic acid derivatives and flavonoids such as quercetin glycosides, rutin and kaempferol [6,9,27]. These aforementioned compounds are of increasing interest due to their ability to scavenge free radicals. ...
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.
... Our group has reported on the isolation and structure elucidation (by NMR and HREISMS) of over 70 phytochemicals, from the sugar, red, and sycamore (A. pseudoplatanus) maples [3][4][5][6][7]. Among these species, only the red maple yielded glucitol-core containing gallotannins (GCGs) [3,4,6]. ...
... pseudoplatanus) maples [3][4][5][6][7]. Among these species, only the red maple yielded glucitol-core containing gallotannins (GCGs) [3,4,6]. These compounds have been reported, by our group [8][9][10][11][12][13][14][15], and others [16][17][18][19][20], to show a wide range of in vitro and in vivo biological effects including, antioxidant, anti-diabetic, anti-α-glucosidase, anti-glycation, anticancer, and skin-health promoting effects. ...
... The injection volume was 10 μL and the flow rate was 0.75 mL/min. A gradient mobile phase solvent system consisting of solvent A (0.1% aqueous trifluoroacetic acid) and solvent B (MeOH) was used as follows: 0-50 min, 5%-46% B. The HPLC profile was monitored at 220 nm and compounds 1-9 were identified by comparison of their retention times to authentic standards previously isolated by our laboratory from red maple [3,4,6]. ...
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), maplexins B, D, and F (4-6), methyl syringate (7), methyl gallate (8), and 3-methoxy-4-hydroxyphenol-1-β-D-(6-galloyl)-glucopyranoside (9). In addition, one sesquiterpenoid, namely, pubineroid A (10), was isolated and identified (by NMR).
... Our laboratory has conducted extensive studies on several maple species and their derived extracts, including the red maple, which has led to the identification of over 100 compounds with anti-oxidant, anti-α-glucosidase, anticancer, anti-glycation, and anti-neurodegenerative activities [13][14][15][16][17][18][19][20][21][22][23]. Herein, we developed and evaluated Maplifa ™ , a proprietary standardized phenolic-enriched extract from red maple leaves, for its skin-whitening cosmetic applications. ...
... Our laboratory has previously reported on the comprehensive isolation and identification of phytochemicals, primarily phenolics, from the leaves, flowers, bark, and stems of the red maple species [21][22][23]. Therefore, using these chemical standards, Maplifa ™ was prepared by proprietary protocols developed in our laboratory. ...
... All GCGs (see Fig. 1a for the chemical structures for ginnalins A-C and maplexins F and J) were generated in our laboratory as previously reported [19,[21][22][23]. ...
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.
... The widely studied prototypical gallotannin, 1,2,3,4,6-penta-O-galloyl-β-D-glucose, commonly known as pentagalloyl glucose (PGG), has been shown to have αglucosidase inhibitory and antidiabetic effects in both in vitro and in vivo studies [1]. While the majority of gallotannins identified to date contain glucose as their polyol core, only members of the maple (Acer) genus, in the entire plant kingdom, are reported to produce gallotannins with a glucitol core instead [2][3][4][5][6]. Our group and others have shown that these 'glucitol-containing' gallotannins display potent α-glucosidase inhibitory properties which, similar to PGG, is influenced by the number, type, and location of substituents on their glucitol core [5][6][7]. ...
... While the majority of gallotannins identified to date contain glucose as their polyol core, only members of the maple (Acer) genus, in the entire plant kingdom, are reported to produce gallotannins with a glucitol core instead [2][3][4][5][6]. Our group and others have shown that these 'glucitol-containing' gallotannins display potent α-glucosidase inhibitory properties which, similar to PGG, is influenced by the number, type, and location of substituents on their glucitol core [5][6][7]. Maple species are proven sources of these bioactive polyphenols [8], but there are several members, including the sycamore maple (A. pseudoplatanus L.), which remain uninvestigated. ...
... In continuation of our group's search for α-glucosidase inhibitory gallotannins from maple species [5,6], herein we focused our attention on the leaves of the sycamore maple. This project led to the isolation and structure elucidation of thirty-nine compounds, including a new gallotannin, 1,2,3-tri-O-galloyl-6-O-(phydroxybenzoyl)-β-D-glucopyranoside (1), along with thirty-eight known compounds (2-39) consisting of five gallotannins, one ellagitannin, thirteen flavonoids, eight hydroxycinnamic acids, ten benzoic acid derivatives, and two sesquiterpenoids (structures of the compounds are provided in the Supplementary Data Figure S2). ...
The maple (Acer) genus is a reported source of bioactive (poly)phenols, including gallotannins, but several of its members, such as the sycamore maple (A. pseudoplatanus), remain uninvestigated. Herein, thirty-nine compounds, including a new gallotannin, 1,2,3-tri-O-galloyl-6-O-(p-hydroxybenzoyl)-β-Dglucopyranoside (1), and thirty-eight (2-39) known compounds, consisting of four gallotannins, one ellagitannin, thirteen flavonoids, eight hydroxycinnamic acids, ten benzoic acid derivatives, and two sesquiterpenoids, were isolated from sycamore maple leaves. Their structures were determined based on NMR and mass spectral analyses. The isolates were evaluated for α-glucosidase inhibitory and antioxidant activities. Among the isolates, the gallotannins were the most potent α-glucosidase inhibitors with thirteen-fold more potent activity compared with the clinical drug, acarbose (IC50 = 16-31 vs. 218 μM). Similarly, the gallotannins showed the highest antioxidant activities, followed by the other phenolic sub-classes, while the sesquiterpenoids were inactive.
... Nowadays, only the sap of the red maple is currently being utilized, primarily to produce the natural sweetener, maple syrup [2]. Given the anecdotal and ethnomedicinal uses of various parts of the red maple, our laboratory initiated a program of studies to isolate and identify its bioactive constituents [3][4][5]. Our previous work on red maple bark and stems yielded several gallotannins, some of which were more potent inhibitors of α-glucosidase than the clinical drug, acarbose [4,5]. ...
... Given the anecdotal and ethnomedicinal uses of various parts of the red maple, our laboratory initiated a program of studies to isolate and identify its bioactive constituents [3][4][5]. Our previous work on red maple bark and stems yielded several gallotannins, some of which were more potent inhibitors of α-glucosidase than the clinical drug, acarbose [4,5]. We also reported that a red maple bark extract regulated blood glucose levels with comparable activity with acarbose in an animal model [6]. ...
... All of the isolates were evaluated for αglucosidase inhibitory activities, along with the positive control, acarbose. In addition, fifteen compounds (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25) were identified in red maple leaves and flowers using HPLC-DAD methods by comparison with chemical standards previously isolated from the stems and bark of this species [3][4][5]. ...
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 alpha-glucosidase enzyme inhibitory activities.
... The red maple species has been used in folk medicine to treat multiple disease, such as sores, back pain, and cough (Bi et al., 2016). In the course of our group's interest in developing nutraceuticals from red maple, we have conducted exhaustive phytochemical investigations on its different plant parts and have isolated and identified a series of GTs with an uncommon 1,5-anhydro-glucitol core, named ginnalins and maplexins, polyphenols which are only produced by some Acer species in the entire plant kingdom (Ma et al., 2016;Yuan, Wan, Liu, & Seeram, 2012). These 1,5-anhydro-glucitol core containing gallotannins (GCGs) possess anti-tyrosinase (Ma et al., 2017), antioxidant, anti-glycation (Ma et al., 2016), anti-hyperglycaemia effects (Seeram, Xu, Li, & Slitt, 2012), and α-glucosidase enzyme inhibiting activities . ...
... Kiss & Piwowarski, 2018;Puupponen-Pimia et al., 2013). The red maple is abundant in GCGs, an uncommon type of GTs containing a 1,5-anhydro-glucitol core (Ma et al., 2017;Wan et al., 2012;Yuan et al., 2012). To pursue the development of red maple leaves as a nutraceutical, in the current study, we evaluated the anti-obesity effects of a GCGs-enriched red maple leaves extract (MLE) in HFD-fed mice. ...
Glucitol-core containing gallotannins (GCGs) are characteristic constituents of the red maple (Acer rubrum) species. To pursue the development of red maple for nutraceutical applications, GCGs-enriched red maple leaves extract (MLE) was evaluated for its effects on obesity, gut dysbiosis and short chain fatty acids (SCFAs) production. Our results demonstrated that MLE alleviated high-fat diet-induced obesity, reduced body weight gain and fat mass, improved liver steatosis and insulin resistance, and mitigated adipose hypertrophy and inflammation. Additionally, MLE increased total SCFAs, acetic acid and n-butyric acid content, but exerted no impact on propionic acid production. Moreover, MLE modulated gut microbiota community structure and certain bacteria relative abundance, including Prevotella and Eubacterium. Our work firstly reports a potential association between colon-derived SCFAs production and metabolic improvement due to GCGs-enriched red maple leaves extract administration, and highlights the utilization of red maple gallotannins as a dietary ingredient for preventing obesity and related metabolic diseases.
... To date, maplexin A-J and ginnalin A-C have been isolated and characterized. The molecules possess varying numbers and positions of the phenol units esterified with the 1,5-AG core [29][30][31][32]. These polyphenols were shown to exhibit different bioactivities such as α-glucosidase inhibition and antioxidant activity. ...
... tribenzyloxybenzoyl)-d-glucitol(30); Compound 6 (0.38 g, 1.5 mmol), compound 16 (3.0 g, 6.8 mmol), 2-chloro-1-methylpyridinium iodide (1.7 g, 6.8 mmol), DMAP (0.83 g, 6.8 mmol), TEA (2.0 mL, 14 mmol) in 30 mL of DCM was stirred at rt for 2 days. ...
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.
... In some studies, the structure-activity relationship has been explored. For example, Wan et al. (2012) compared maplexins A-I isolated from A. rubrum L. and concluded that both the number and position of the galloyls attached to 1,5-anhydro-D-glucitol were key to inhibiting the αglucosidase activity. Most of the data have been obtained from in vitro assays, but in vivo evidence is lacking, especially for antitumor studies. ...
... Pycnalin (72), ginnalin A (82), and 3,6-di-O-galloyl-1,5-anhydro-D-glucitol (83), isolated from A. pycnanthum K. Koch, exhibited moderate to potent α-glucosidase inhibitory activity (Ogawa et al., 2011). In addition to its antitumor activity described previously, maplexin E (91), isolated from A. rubrum L., was 20 times more potent than the α-glucosidase-inhibiting drug acarbose (IC 50 of 8 vs. 160 μM) (Wan, 2012). A case study showed that a bark extract of A. rubrum L. significantly decreased the blood glucose levels in mice (Seeram et al., 2012). ...
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.
... The AGI potential of CS and EAE was evaluated in vitro by chromogenic method with minor modifications [19]. The assay was performed in a 96-well microtiter plate. ...
The global prevalence rate of diabetes in 2021 was 6.1% making diabetes one of the top 10 causes of death. Prolonged use of antidiabetic medications is associated with various side effects; therefore, alternative treatment strategies for diabetes need exploration. The antidiabetic properties of Lactiplantibacillus plantarum 2034 was explored both in in vitro and in vivo studies. Secretory metabolites of probiotic L. plantarum 2034 exhibited alpha-glucosidase, alpha-amylase, and lipase inhibitory activities, in vitro. Further, the antidiabetic efficacy of 2034 was evaluated in streptozotocin-nicotinamide-induced diabetic rats. In the therapeutic model, oral administration of L. plantarum resulted in normalization of body weight, fasting blood glucose, total cholesterol (TC), and liver enzymes, and significant (p < 0.05) reduction in insulin and triglyceride (TG) levels. Histological evaluation of pancreas, liver, and kidney showed restoration of normal architecture in probiotic-treated group. Similarly, in a preventive + therapeutic model, 14 days of pre-administration of 2034 in pre, pre + post, and cell-free supernatant resulted in significant reduction in glucose, TG, TC, and liver biochemistry of diabetic rats as compared to untreated diabetic rats. An oral glucose tolerance test showed that the glucose levels normalized within 90 min in all the treated groups. Further, the oxidative stress parameters were also studied that showed that in all the treated groups, the concentration of antioxidant enzymes significantly (p < 0.05) increased as compared to diabetic untreated rats. Thus, administration of L. plantarum 2034 and its metabolites successfully ameliorated hyperglycaemia and hypercholesterolemia in both the models probably due to inhibition of gut enzymes and by increasing the concentration of liver antioxidant enzymes.
Graphical Abstract
... Subsequently, 100 µL of a 0.1 M solution of 4-Nitrophenyl-β-D-glucopyranoside diluted in phosphate buffer (0.1 M pH 6.9) was added and incubated at 25 °C for 30 min. The absorbance was read at 405 nm at the beginning and at the end of the 30 min incubation (Multiskan Go, Thermo Fisher Scientific, USA) [85]. ...
In this study, a beverage made from a combination of Agave sap (AS) and prickly pear juice (PPJ) was analyzed for its nutrients and bioactive and potentially health-promoting compounds. The beverage was evaluated for its ability to act as an antioxidant, regulate glycemic properties, and undergo gut bacterial fermentation in vitro. The major mono- and oligosaccharides present in the beverage were galacturonic acid (217.74 ± 13.46 mg/100 mL), rhamnose (227.00 ± 1.58 mg/100 mL), and fructose (158.16 ± 8.86 mg/mL). The main phenolic compounds identified were protocatechuic acid (440.31 ± 3.06 mg/100 mL) and catechin (359.72 ± 7.56 mg/100 mL). It was observed that the beverage had a low glycemic index (<40) and could inhibit digestive carbohydrases. The combination of ingredients also helped to reduce gas production during AS fermentation from 56.77 cm3 to 15.67 cm3. The major SCFAs produced during fermentation were butyrate, acetate, and propionate, with valerate being produced only during the late fermentation of the AS. This beverage is rich in bioactive compounds, such as polyphenols and dietary fiber, which will bring health benefits when consumed.
... Subsequently, 100 μL of a 0.1 M solution of 4-Nitrophenyl-β-D-glucopyranoside diluted in phosphate buffer (0.1 M pH 6.9) was added and incubated at 25 °C for 30 min. The absorbance was read at 405 nm at the beginning and at the end of the 30 min incubation (Multiskan Go, Thermo Fisher Scientific, USA) (Yuan et al., 2012). ...
A beverage made from a combination of Agave sap (AS) and prickly pear juice (PPJ) was ana-lyzed for its nutrients, bioactive and potentially health-promoting compounds. The beverage was evaluated for its ability to act as an antioxidant, regulate glycemic properties, and undergo gut bacterial fermentation in vitro. The major mono- and oligosaccharides present in the beverage were galacturonic acid (217.74±13.46 mg/100 mL), rhamnose (227.00±1.58 mg/100 mL), and fructose (158.16±8.86 mg/mL). The main phenolic compounds identified were protocatechuic acid (440.31±3.06 mg/100 mL) and catechin (359.72±7.56 mg/100 mL). It was observed that the beverage had a low glycemic index (
... In traditional medicine, the bark of maple has been used in the treatment of ailments like eye diseases and back pain and as a diuretic [15,16]. The extracts obtained from the bark of maple contain phenolic compounds like gallic acid derivatives and flavonoids such as quercetin glycosides, rutin, and kaempferol [7,17,18]. Extracts obtained from 250 g of sugar and red maple bark with a moisture content of 5.6% and 9.5%, ground to particle sizes from 250 to 500 µm, separately extracted using 2.5 L of water as a solvent, for 1 h duration and under conditions of 90 • C achieved the following: total polyphenol content: 19.04 and 40.12 g GAE/100 g DE; total flavonoid content: 1.46 and 1.58 g QE/100 g DE; antioxidant activity (ABTS assay): 45.20 and 128.71 mmol TE/100 g DE (TE-Trolox equivalent) [19]. ...
The Box–Behnken experimental design was used to investigate the effect of subcritical water extraction parameters such as temperature, process duration, and extractor shape on the extract composition and antioxidant activity of Norway maple (Acer platanoides L.) bark extracts. Spectrophotometric (UV-Vis) techniques were employed to evaluate the total polyphenols (TPC) and flavonoids (TFC). The DPPH radical scavenging method was used to evaluate the antioxidant activity of the extracts. The yield of the process was evaluated through the utilization of response surface methodology (RSM). The total polyphenol and flavonoid contents, together with antioxidant activity, are highly dependent on water temperature. The influence of changes in the process duration and the shape of the pressure cell was not observed. A temperature increase from 110 °C to 170 °C caused a 8.9-fold increase in the polyphenol content, 7.2-fold increase in the flavonoid content, and 12.6-fold increase in the antioxidant activity. The highest values for polyphenols, flavonoids, and antioxidant activity occurred at a temperature of 170 °C, which is the upper limit of the temperature variability range for these studies. This study demonstrates the importance of the appropriate selection of extraction parameters in order to obtain the desired chemical composition of the extract.
... Evaluation of α-glucosidase inhibitory activity The α-glucosidase inhibitory activity was measured according to the literature [18]. Each sample (20 µL) in DMSO solution was added to 100 µL α-glucosidase solution (pH 6.9, 0.1 U/mL, in 0.1 M phosphate buffer). ...
This study reported the isolation and identification of bioactive compounds from Dioscorea nipponica Makino, a plant used in traditional medicine for various ailments. Nine compounds were isolated, including a new compound named as diosniposide E, which was elucidated by analyzing its ¹H-NMR, ¹³C-NMR, DEPT, COSY, HMBC and MS data and comparing them with data available in literature. The other eight compounds were identified as known compounds. Theoretical calculations of energy and the generation of a molecular electrostatic potential surface map were employed to assess the antioxidant capacity of nine compounds, the calculation results exhibited that compounds 5 and 6 had strong antioxidant capacities. To further evaluate the antioxidant activities of the investigated compounds, the DPPH and ABTS assays were conducted. The results from the DPPH scavenging activity test revealed that compounds 4–6 exhibited enhanced scavenging activities compared to L-ascorbic acid, while displaying similar efficacy to trolox. Moreover, the ABTS scavenging activities of compounds 4–6 were found to surpass those of L-ascorbic acid and trolox. In terms of α-glucosidase inhibition, compounds 3 and 4 displayed remarkable inhibitory activities that surpassed the effects of acarbose. Additionally, compound 2 exhibited potent anticholinesterase activities, outperforming donepezil. This research provides insights into the potential bioactive compounds present in Dioscoreanipponica Makino and may contribute to its use in traditional medicine.
... The absorbance was recorded at 492 nm on a microplate spectrophotometer. 1 was used as a positive reference. IC 50 values (the concentrations required to scavenge 50% of the hydroxyl radicals present in the test solution) were calculated and expressed as the mean ± SD. α-Glucosidase Inhibition Assay α-Glucosidase inhibition activity was assayed according to the method with slight modifications (Yuan et al., 2012). Each sample (20 µL) in DMSO solution (from 0.1 to 10 mM) was added to 100 µL of α-glucosidase solution (pH 6.9, 0.1 U/mL, in 0.1 M phosphate buffer). ...
Abstract A series of Trolox amide derivatives were synthesized by modifying the carboxyl groups of Trolox. Thirty target compounds were obtained and characterized through nuclear magnetic resonance and mass spectrometry. Trolox derivatives were employed to explore the potential structure-antioxidant activity relationships. The antioxidant activities of these compounds were evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP) and hydroxyl radical assays. DPPH scavenging activity test results illustrated that compounds exhibited scavenging activities similar to L-ascorbic acid and Trolox, with compounds 14a, 18a, 24a and 26a in particular exhibiting higher scavenging activities than L-ascorbic acid. The results demonstrated that compounds displayed ABTS scavenging activities similar to L-ascorbic acid and Trolox, with compounds 26a and 29a in particular having potency twofold higher. FRAP assay results indicated that compounds 11a, 19a, 25a, 29a and 30a had activity similar to Trolox. The results revealed that compounds 6a and 19a had similarly high hydroxyl radical-scavenging activities as Trolox. The results of α-glucosidase experiments uncovered that compounds 10a, 25a, 28a and 29a had excellent inhibitory activity, which was similar to that of acarbose and different from Trolox. The results of acetylcholinesterase and butyrylcholinesterase experiments demonstrated that some compounds had weak anticholinesterase activities. 26a and 29a are important Trolox derivatives with better biological activity profiles and deserve further study.
... rubrum L.) species is local to eastern North America that are used for medicinal purposes by Native Americans [7]. Maplerins A-I are a group of structurally related gallotannins that are isolated from the red maple species [8,9]. provide evidence that Maplexins A-I provide anticancer activity against human tumorigenic (colon. ...
Since the dawn of time, plants have been employed as therapeutic agents. The high expense and severe side effects of conventional chemotherapy have lowered public acceptance and fueled the hunt for alternatives. Alternative therapy methods, such as phytochemicals, have become more widely available and cost-effective. Loss of mitochondrial membrane potential, release of cytochrome-c, and other processes and pathways are all involved in the anticancer activity of plant- derived therapeutic substances. Anti-apoptotic proteins are down regulated, while pro-apoptotic proteins are up-regulated. Caspase, Fas, FADD, p53, and c-Jun signaling pathways are activated; Akt signaling pathway is inhibited; phosphorylation of ERK, P13K, Raf, survivin gene, STAT 3, and NF-kB is inhibited. In-vitro testing of skin cancer cell lines models allows researchers to discover the mechanisms of action of chemicals derived from plants against a variety of skin malignancies. As a result, the goal of this study is to provide an overview of plant-derived anti-cancer chemicals that have been found to have promising anti-carcinogenic activities.
... The determination of α-amylase and α-glucosidase enzyme inhibition assay followed a previously described method with some modifications (24,25). Briefly, for the α-glucosidase assay, in a 96-well plate, 50 µL of CP solution with different concentrations, or blank (distilled water) was added, then mixed with 100 µL of 1 U/mL α-glucosidase (dissolved in 0.1 M PBS, pH 6.8), whereafter the mixed solution was incubated for 10 min at 37 • C. Finally, 50 µL of 5 mM PNPG (dissolved in 0.1 M PBS, pH 6.8) was added to each well and incubated for 5 min at 37 • C before the absorbance was read at 405 nm using a SpectraMax M2 multimode microplate reader. ...
The peel of Citrus reticulata “Chachi” (CP) possesses various health-promoting benefits and is not only one of the most famous Chinese herbal medicine, but also an ingredient in fermented foods. In the present study, the effects of storage years (1-, 3-, 4-, 5-, 6-, and 11-years) on the chemical profiling and potential bioactive compounds of CP were compared by metabolomics and in vitro bioactivity analysis. With the increase of storage time, the content of hesperidin significantly decreased, but nobiletin, 3,5,6,7,8,3′,4′-heptamethoxyflavone, and tangeretin were increased. Meanwhile, the antioxidant activity of CP was enhanced. Phenolic acids, flavonol glycosides, fatty acids, and alkyl glycosides were marker compounds that were responsible for distinguishing the storage time of CP. Correlation analysis suggested that some polyphenols including quercetin-glucoside, quinic acid, trihydroxydimethoxyflavone, and rutin were potential antioxidant compounds in CP. The dichloromethane and n-butanol fractions showed the better antioxidant capacity and inhibitory effects on glucose-hydrolysis enzymes. They mainly contained ferulic acid, nobiletin, 3,5,6,7,8,3′,4′-heptamethoxyflavone, kaempferol, and hesperidin.
... A large number of the food-based LAB are now potential probiotics. In this study, two concentrations of KS-TN11 were evaluated for its a-glucosidase inhibitory potential to confirm its anti-diabetic property using chromogenic method (Yuan et al., 2012;Bajpai et al., 2016). A 50 ll of various concentrations (2.5 mg and 5 mg) of SK-TN11 and 100 ll of a-glucosidase was dissolved in 0.1 M PBS, the solutions were gently mixed in a 96-well microplate and incubated for 10 min at 25°C. ...
... Maple bark is a rich source of phenolics compounds and has glucidase inhibitory and anticancer activities (Yuan et al., 2011(Yuan et al., , 2012. Several plant parts and their extracts have been used o characterization the content of total phenolics. ...
Plant extracts contain a varied range of chemicals such as terpenoids, phenolic compounds, alkaloids, glucosinolates, and various organic acids. These chemicals are responsible for their unique nature and perceived biological activity of plant extracts. Owing to the wide acclaimed biological activities of plant extracts, they have been used as natural ingredients and have received significant renewed interest recently. Several plant extracts have been used as commercial preservatives in food because of their green image. The current chapter discusses various chemicals present in plant extracts and emphasizes the structure activity relationship of these chemicals.
... Maple bark is a rich source of phenolics compounds and has glucidase inhibitory and anticancer activities (Yuan et al., 2011(Yuan et al., , 2012. Several plant parts and their extracts have been used o characterization the content of total phenolics. ...
In recent years, great interest has been focused on using natural extracts of plant origin because of the possible adverse effects associated with the consumption of synthetic products being manufactured in the markets. A variety of plant extracts are known to have rich source of vitamins, minerals, phenolic compounds, antioxidants, alkaloids, and many other secondary metabolites. The interest in these natural components is not only due to their biological value but also to their economic impact. These secondary metabolites have the potential to cure various chronic diseases. Being an integral part of traditional medicine, these extracts need to be explored for various phytochemcial characterization, isolation, and their mechanism.
... The α-glucosidase assay was performed using a slightly modified version of the method proposed by Yuan et al. [58]. A 50 µL aliquot of the test sample and 100 µL of yeast α-glucosidase (1 U/mL of α-glucosidase dissolved in 0.1 phosphate buffer, pH 6.9) were premixed and incubated in 96-well plates for 10 min at 25 °C. ...
This study investigated the in vitro inhibitory potential of different solvent extracts of leaves of Barbeya oleoides on key enzymes related to type 2 diabetes mellitus (α-glucosidase and α-amylase) in combination with an aggregation assay (using 0.01% Triton X-100 detergent) to assess the specificity of action. The methanol extract was the most active in inhibiting α-glucosidase and α-amylase, with IC50 values of 6.67 ± 0.30 and 25.62 ± 4.12 µg/mL, respectively. However, these activities were significantly attenuated in the presence of 0.01% Triton X-100. The chemical analysis of the methanol extract was conducted utilizing a dereplication approach combing LC-ESI-MS/MS and database searching. The chemical analysis detected 27 major peaks in the negative ion mode, and 24 phenolic compounds, predominantly tannins and flavonol glycosides derivatives, were tentatively identified. Our data indicate that the enzyme inhibitory activity was probably due to aggre-gation-based inhibition, perhaps linked to polyphenols.
... The α-glucosidase inhibitor, acarbose (trade name, Glucobay or Precose), is used as a clinical treatment for glycemic control over hyperglycemia. Our group has had a long research interest in the identification of α-glucosidase inhibitors from medicinal plants (Liu et al. 2018;Omar et al. 2012;Wan et al. 2012;Yuan et al. 2013Yuan et al. , 2012bYuan et al. , 2012aZhang et al. 2015) and the evaluation of these natural products for their potential mechanisms of inhibition . ...
Objective
Cannabidiol (CBD) has been reported to have anti-diabetic effects in pre-clinical and clinical studies but its inhibitory effects on α -glucosidase, a carbohydrate hydrolyzing enzyme, remain unknown. Herein, we evaluated CBD’s inhibitory effects on α -glucosidase using in vitro assays and computational studies.
Methods
CBD’s inhibitory effect on α -glucosidase activity was evaluated in a yeast enzymatic assay and by molecular docking. The stability of CBD in simulated gastric and intestinal fluids was evaluated by high-performance liquid chromatography analyses.
Results
CBD, at 10, 19, 38, 76, 152, 304, 608, and 1216 μM, inhibited α -glucosidase activity with inhibition of 17.1, 20.4, 48.1, 56.6, 59.1, 63.7, 74.1, and 95.4%, respectively. Acarbose, the positive control, showed a comparable inhibitory activity (with 85.1% inhibition at 608 μM). CBD’s inhibitory effect on α -glucosidase was supported by molecular docking showing binding energy (-6.39 kcal/mol) and interactions between CBD and the α -glucosidase protein. CBD was stable in simulated gastric and intestinal fluids for two hours (maintained ≥ 90.0%).
Conclusions
CBD showed moderate inhibitory effect against yeast α -glucosidase activity and was stable in gastric and intestinal fluids. However, further studies on CBD’s anti- α -glucosidase effects using cellular and in vivo models are warranted to support its potential application for the management of type II diabetes mellitus.
... This led to the discovery of a series of unique GTs, namely, glucitol-core containing gallotannins (GCGs), from the red maple (Acer rubrum) species (C. Li & Seeram, 2018;Wan et al., 2012;Yuan, Wan, Liu, & Seeram, 2012;Y. Zhang, Ma, Yuan, & Seeram, 2015). ...
Glucitol-core containing gallotannins (GCGs) from the red maple (Acer rubrum) species have been reported to exhibit skin beneficial activities but their inhibitory effects on elastase remain unclear. Herein, we evaluated a series of GCGs for their anti-elastase activity, skin permeability, and cytoprotective effects in human keratino-cytes HaCaT cells. GCGs' anti-elastase effects were enhanced as their number of galloyl groups increased, which may be attributed to the formation of more stable protein-ligand complexes. In addition, GCGs were predicted to have moderate skin permeability and ginnalin A (GA) showed favorable permeability in the PAMPA model and cell uptake assay. Moreover, GA, ginnalin B, and maplexin F (at 50 µM) reduced H 2 O 2-induced reactive oxygen species in HaCaT cells by 70.8, 92.8, and 84.6%, respectively. In conclusion, red maple GCGs are skin permeable elastase inhibitors with antioxidant activity, which may contribute to their overall skin beneficial effects and support their potential for cosmeceutical applications.
... The present work is focused on red maple (Acer rubrum L. 1753) trees that are largely distributed in Europe with the objective of determining which PPs could be responsible for the PDI properties of their leaf extracts. The red maple leaves are enriched in PPs and numerous phenolic compounds have been identified in aerial parts of Acer species, among them gallate derivatives and gallotannins [26][27][28][29][30][31][32]. Structurally, these compounds have a high content in aromatic hydroxyl groups providing freeradical scavengers to module cell redox balance [33]. ...
Red maple leaf extracts (RME) were tested for their plant defense inducer (PDI) properties. Two extracts were obtained and compared by different approaches: RME1 using ethanol–water (30–70%, v/v, 0.5% HCl 1N) and RME2 using pure water. Both extracts titrated at 1.9 g L−1 in polyphenols and infiltrated into tobacco leaves efficiently induced hypersensitive reaction-like lesions with topical accumulation of auto-fluorescent compounds noted under UV and scopoletin titration assays. The antimicrobial marker PR1, β−1,3-glucanase PR2, chitinase PR3, and osmotin PR5 target genes were all upregulated in tobacco leaves following RME1 treatment. The alkaline hydrolysis of RME1 and RME2 combined with HPLC titration of gallic acid revealed that gallate functions were present in both extracts at levels comprised between 185 and 318 mg L−1. HPLC-HR-MS analyses and glucose assay identified four gallate derivatives consisting of a glucose core linked to 5, 6, 7, and 8 gallate groups. These four galloyl glucoses possessed around 46% of total gallate functions. Their higher concentration in RME suggested that they may contribute significantly to PDI activity. These findings define the friendly galloyl glucose as a PDI and highlight a relevant methodology for combining plant assays and chemistry process to their potential quantification in crude natural extracts.
... The α-glucosidase inhibitory activity of samples was determined according to previous report with slight modifications [20] . Briefly, 20 µL of samples, 50 µL of 0.1 mol·L -1 phosphate buffer (pH 6.9) and 10 µL the enzyme solution (1 U·mL -1 ) were plated into 96-well plates and incubated at 37 °C for 20 min. ...
The aim of the study was to determine the feasibility of the Vitellaria paradoxa nutshell as a new medicinal resource for treating diabetes. A total of forty-one compounds were identified by HPLC-DAD-Q-TOF-MS and phytochemical methods in V. paradoxa nutshell methanol extract. Based on HPLC fingerprints, four characteristic constituents were quantified and the origin of twenty-eight V. paradoxa nutshells from seven sub-Saharan countries was compared, which were classified into three groups with chemometric method. Twenty-eight samples contained high total phenolic content, and exhibited moderate-higher antioxidant activity and strong α-glucosidase inhibitory activity. Furthermore, all fractions and isolated compounds were evaluated for their antioxidant and α-glucosidase inhibitory activities, and α-glucosidase inhibitory action mechanism of four characteristic constituents including protocatechuic acid, 3, 5, 7-trihydroxycoumarin, (2R, 3R)-(+)-taxifolin and quercetin was investigated via molecular docking method, which were all stabilized by hydrogen bonds with α-glucosidase. The study provided an effective approach to waste utilization of V. paradoxa nutshell, which would help to resolve waste environmental pollution and provide a basis for developing potential herbal resource for treating diabetes.
... A large number of the food-based LAB are now potential probiotics. In this study, two concentrations of KS-TN11 were evaluated for its a-glucosidase inhibitory potential to confirm its anti-diabetic property using chromogenic method (Yuan et al., 2012;Bajpai et al., 2016). A 50 ll of various concentrations (2.5 mg and 5 mg) of SK-TN11 and 100 ll of a-glucosidase was dissolved in 0.1 M PBS, the solutions were gently mixed in a 96-well microplate and incubated for 10 min at 25°C. ...
Aquatic animals are known for their myriad of beneficial bacteria with diverse biologically active compounds. The current study was aimed to isolate and characterize potentially beneficial lactic acid bacteria from Nile Tilapia and evaluate their pharmaceutical applications. The fish samples were dissected and stomach, intestine, and gills were collected and serially diluted for the isolation of lactic acid bacteria (LAB) on BCP agar media. Identification of isolate was carried by biochemical and molecular characterization using API kit and 16S rRNA gene sequencing analysis, respectively. Further, KS-TN11 was assessed for α-glucosidase inhibitory potential using the chromogenic method. A lactic acid bacterium KS-TN11 was isolated from the stomach of Nile Tilapia and identified as Leuconostoc mesenteroides. Effect of KS-TN11 on lipid accumulation in adipocytes was done by using Oil Red O staining. The isolate showed strong antibacterial activity against a number of pathogenic bacteria in vitro. In addition, L. mesenteroides KS-TN11 KS-TN11 (50 mg/ml and 100 mg/ml) tends to inhibit adipogenesis in 3T3-L1 adipocytes and thus may have possible anti-obesity effects. Moreover, L. mesenteroides KS-TN11 exhibited substantial α–glucosidase inhibitory activities by 41.33% at 50 mg/ml and 64% at 100 mg/ml, respectively. The bacterium showed potent antibacterial activity against a number of pathogenic bacteria; in addition to alpha-glucosidase activity, and inhibition of lipid accumulation in 3T3-L1 cell line. These results reinforce KS-TN11 as a novel bacterium with an impending pharmaceutical application.
... Determination of α-glucosidase inhibitory activity of Meju samples. α-Glucosidase inhibitory activity of Meju samples supplemented with plant extracts was evaluated according to a chromogenic method 25 , with minor modifications. Briefly, various concentrations (5, 10, 20, and 50 mg/ml) of Meju samples (50 µl) and 100 µl of α-glucosidase (1.0 U/ml) dissolved in 0.1 M phosphate buffer (pH 6.9) were mixed in a 96-well microplate and incubated at 25 °C for 10 min. ...
We developed a novel type of Meju starter culture using single and combined extracts of Allium sativum (garlic clove), Nelumbo nucifera (lotus leaves), and Ginkgo biloba (ginkgo leaves) to improve the quality and functionality of Meju-based fermented products. Meju samples fermented with plant extracts (10 mg/ml) showed phenolic contents of 11.4–31.6 mg/g (gallic acid equivalents). Samples of extracts (garlic clove, lotus leaves, ginkgo leaves and their combination) fermented with Meju strongly inhibited tyrosinase, α-glucosidase, and elastase activities by 36.43–64.34%, 45.08–48.02%, and 4.52–10.90%, respectively. Specifically, ginkgo leaves extract added to fermented Meju samples at different concentrations (1% and 10%) strongly inhibited tyrosinase, α-glucosidase, and elastase activities and exhibited a potent antibacterial effect against Bacillus cereus with a significant reduction in bacterial counts compared with the effects observed for garlic clove and lotus leaf added to Meju samples. Scanning electron microscopy revealed severe morphological alterations of the B. cereus cell wall in response to ginkgo leaf extracts. Gas chromatographic mass spectroscopic analysis of plant extract-supplemented Meju samples and control Meju samples identified 113 bioactive compounds representing 98.44–99.98% total extract. The proposed approach may be useful for the development of various fermented functional foods at traditional and commercial levels.
... Traditional and anecdotal medicinal claims for other parts of these plants in Amerindian medicine have also incited the interest to study different maple tissues. Previous phytochemical studies have reported gallotannins, procyanidins, lignans, coumarins, and flavonoids in leaves, bark and wood of the red maple and sugar maple species [8][9][10][11]. ...
We are reporting here the results of the first study on phenolic constituents
of hot water and aqueous ethanol extracts of sugar (Acer saccharum Marsh)
and red maple (Acer rubrum L.) buds. The bud extracts were compared for
their phenolic fingerprints using Thin Layer Chromatography (TLC) supported
by chemometric tools. The NP/PEG (Natural Products/Polyethylene Glycol)
derivatized TLC plate was photographed using a digital camera. The image
of each plate was subsequently processed using the Image J program (1.50a
version). The global analysis of TLC tracks showed major differences in colours,
intensities, and positions of spots on the phenolic fingerprint of the extracts
of buds from red and sugar maple. The chemometric approach revealed that
phenolic compounds with lower Retention factor (Rf) were revealed for sugar
maple extracts, while those exhibiting bright intensity spots at Rf between 0.3
and 0.8 were observed for red maple extracts, thus indicating the differences
between their phenolic fingerprints. The solvent used for extraction seems also
to have an effect on the phenolic compounds extracted from maple buds. The
results of the principal component analysis suggest that there are significant
differences in the phenolic fingerprints between the bud extracts of sugar and
red maple which are related to both the species and the solvent applied for
extraction. The obtained results demonstrate the interest to apply TLC as an
efficient method in screening of phytochemicals, especially in combination with
new informatics and statistical tools.
... The α-glucosidase inhibitory activity was determined based on previous literature (Yuan et al. 2012). In brief, 50µL of sample, 50µL of 0.1Mm of phosphate buffer (pH 6.9) and 100µL of α-glucosidase solution (pH 6.9, 0.2 U/mL, in 0.1M phosphate buffer) were added in a 96-well plates (25°C for 15min). ...
Cortex Lycii (root back of Lycium chinense) has is a famous traditional Chinese medicine which displays several
pharmacological activities including antioxidant and antidiabetic properties. We investigated the effect of the ethyl
acetate fraction (QCL) of Cortex Lycii on the enzymes involved in the metabolism of carbohydrate in diabetic rat models.
Streptozotocin-nicotinamide (110 and 65 mg/kg body weight, respectively) was used to induce diabetes. Diabetic rats
were treated with QCL (100, 200 and 400 mg/kg) and glibenclamide (600 µg/kg) daily for six weeks. Upon the completion
of treatment, fasting blood glucose (FBG), insulin, glycosylated haemoglobin (HbA1c), haemoglobin (Hb), hexokinase,
glucose-6-phosphate dehydrogenase, glucose-6-phosphatase, phosphoenolpyruvate carboxykinase and
fructose-1,6-bisphosphatase levels were measured by biochemical assays. Likewise, the body weight, food and water
intake was monitored and measured. Diabetic rats displayed significant elevation in the blood glucose, glycosylated
hemoglobin and a marked decrease in plasma insulin and hemoglobin. Furthermore, the levels of key enzymes including
fructose-1,6-bisphosphatase, glucose-6-phosphatase phosphoenolpyruvate carboxykinase were significantly increased
while the activity levels of hexokinase, glucose-6-phosphate dehydrogenase and glycogen were significantly down
regulated in diabetic rats. However treatment of diabetic rats with Cortex Lycii led to a significant reduction the FGB,
food and water intake and an increase in the plasma insulin level. Treatment with Cortex Lycii also reversed the altered
activity profiles of the key enzymes mentioned above in a dose dependent manner. Our results suggested that Cortex
Lycii has a promising therapeutic option in the management of diabetic complications relating to glucose homeostasis
and carbohydrate metabolism
... It is not known whether LAB colonizing the human gut possess inhibitory potential against digestive enzymes glucosidases. Hence, this study was undertaken to evaluate α-glucosidase inhibitory potential of 1I1 in order to confirm its type II anti-diabetic efficacy according to the chromogenic method with minor modifications as described previously [36]. Briefly, 50 μl of various concentrations (100, 50, 25, 5 and 1 mg/ml) of 1I1 ethanol extract and 100 μl of α-glucosidase dissolved in 0.1 M phosphate buffer (pH 6.9), were mixed in a 96-well microplate and incubated at 25°C for 10 min. ...
Background
There are still a large variety of microorganisms among aquatic animals which have not been explored for their pharmacological potential. Hence, present study was aimed to isolate and characterize a potent lactic acid bacterium from fresh water fish sample Zacco koreanus, and to confirm its pharmacological potential.
Methods
Isolation of lactic acid bacteria (LAB) from fresh water fish samples was done using serial dilution method. Biochemical identification and molecular characterization of selected LAB isolate 1I1, based on its potent antimicrobial efficacy, was accomplished using API kit and 16S rRNA gene sequencing analysis. Further, 1I1 was assessed for α-glucosidase and tyrosinase inhibitory potential as well as antiviral efficacy against highly pathogenic human influenza virus H1N1 using MDCK cell line in terms of its pharmacological potential.
Results
Here, we first time report isolation as well as biochemical and molecular characterization of a lactic acid bacterium Lactobacillus sakei 1I1 isolated from the intestine of a fresh water fish Z. koreanus. As a result, L. sakei 1I1 exhibited potent antimicrobial effect in vitro, and diameter of zones of inhibition of 1I1 against the tested pathogens was found in the range of 13.32 ± 0.51 to 23.16 ± 0.32 mm. Also L. sakei 1I1 at 100 mg/ml exhibited significant (p < 0.05) α–glucosidase and tyrosinase inhibitory activities by 60.69 and 72.59 %, in terms of its anti-diabetic and anti-melanogenic potential, respectively. Moreover, L. sakei 1I1 displayed profound anti-cytopathic effect on MDCK cell line when treated with its ethanol extract (100 mg/ml), confirming its potent anti-viral efficacy against H1N1 influenza virus.
Conclusions
These findings reinforce the suggestions that L. sakei 1I1 isolated from the intestine of fresh water fish Z. koreanus might be a candidate of choice for using in pharmacological preparations as an effective drug.
Four undescribed compounds (two 1,5-anhydro-d-glucitol derivatives and two galloyl derivatives) and fourteen known compounds were isolated and structurally identified from leaves of Acer ginnala Maxim. (Amur maple). Structures and absolute configurations of the four undescribed compounds were determined using extensive analysis of NMR spectroscopic, HRESI-MS, modified Mosher ester method, and comparison with spectroscopic data of known compounds. Bioactivity evaluation revealed that the isolated 1,5-anhydro-d-glucitol derivative, galloylated flavonol rhamnosides, and galloylated flavanols had inhibitory effects on both protein tyrosine phosphatase-1B (PTP1B, IC50 values ranging of 3.46-12.65 μM) and α-glucosidase (IC50 values ranging of 0.88-6.06 μM) in comparison with a positive control for PTP1B (ursolic acid, IC50 = 5.10 μM) or α-glucosidase (acarbose, IC50 = 141.62 μM). A combination of enzyme kinetic analysis and molecular docking provided additional evidence in favor of their inhibitory activities and mechanism. These data demonstrate that A. ginnala Maxim. together with its constituents are promising sources of potent candidates for developing novel anti-diabetic medications.
Sixteen tyrosol derivatives were synthesized and characterized by NMR and HR-MS. The antioxidant activity of those compounds was evaluated using four different assays. The results showed that some target compounds displayed better antioxidant activity than L-ascorbic acid and Trolox. Five target compounds exhibited more potent α-glucosidase inhibition activity (18.1–56.7 μM) than acarbose (60.9 μM). Eight target compounds showed some anticholinesterase activities.
To find a potent α-glucosidase inhibitor, 24 tyrosol derivatives with different substituents located at the meta, ortho, or para position of the phenyl group have been synthesised via the Mitsunobu reaction, characterised by ¹H NMR, ¹³C NMR, ESI-MS and IR and evaluated for inhibition. The derivatives possessed varying degrees of in vitro inhibitory activity against α-glucosidase and a relationship between the structure and activity was subsequently established for all compounds. Two of these compounds with substituents at the para position showed significant inhibitory effects surpassing that of the control standard acarbose. Molecular docking studies performed to better understand the binding interactions between the enzyme and the two most active compounds showed substantial binding within the active site of α-glucosidase. Taken together, these results indicate that the position of the substituent plays a crucial role in this inhibition and may facilitate the development of new α-glucosidase inhibitors.
The aerial parts of Artemisia gmelinii Weber ex Stechm were collected from the northeast of China. The essential oil was obtained by hydrodistillation and analysed by GC-MS. A set of 66 compounds were identified representing 99.1% of the oil composition. The major compounds in the oil were cyclobutaneethanol, endo-borneol, germacrene D, eucalyptol, selin-6-en-4α-ol, bisabolone oxide A, caryophyllene and terpinen-4-ol. Moreover, the essential oil was evaluated for its antioxidant, antidiabetic, and anticholinesterase activities in vitro. Additionally, the antioxidant potential of the oil was evaluated using DPPH and ABTS assays. The oil showed good antidiabetic activity with an IC50 of 63.2 µg/mL, which was similar to that of the positive control acarbose, and weak anticholinesterase activities. These findings demonstrated that the essential oil of Artemisia gmelinii may be a good natural antidiabetic.
The red maple and sugar maple (Acer rubrum and A. saccharum, respectively) contain acertannins (ginnalins and maplexins), galloylated derivatives of 1,5-anhydro-D-glucitol (1,5-AG, 1). These compounds have a variety of potential medicinal properties and we have shown that some of them promote the expression of ceramide synthase 3. We now report on the beneficial effects of ginnalin B, (6-O-galloyl-1,5-AG, 5), leading to acceleration of skin metabolism and reduction of the turnover time. Ginnalin B dose-dependently increased the relative amount of keratin 10, keratin 1, and filaggrin gene, with maximal increase of 1.7-, 2.9, and 5.2-fold at 100 μM, respectively. The validation study showed that it had superior capacity to induce multiple stages of keratinocyte differentiation and significantly elevated the immunostaining site of keratin 10 and filaggrin in a 3-dimensional cultured human skin model, by 1.2 and 2.8-fold, respectively. Furthermore, ginnalin B caused the arrest of proliferation at the G 0 /G 1 phase but it did not induce apoptotic cell death in normal human keratinocytes. Molecular studies revealed that ginnalin B up-regulated the levels of NOTCH1 and a concomitant increase p21 expression. Ginnalin B, therefore, represents a new class of promising functional and medical cosmetic compound and it could contribute to the maintenance of homeostasis of the epidermis.
Understanding of the phytochemical profiles and bio-active compounds is extremely important for the application of new plant resources in health food and medicinal industry. This research was designed to elucidate the phytochemical profiles of Acer palmatum Thunb (APT), Acer truncatum Bunge (ATB), Acer mono Maxim. (AMM) and Acer buergerianum Miq. (ABM) leaf extracts by ultra-high performance liquid chromatography coupled to quadruple time-of-flight tandem mass spectrometry (UPLC-QTOF-MS/MS), content of polyphenols and α-glucosidase inhibition were measured, the α-glucosidase inhibitors (AGIs) were also screened by ultra-filtration combined with UPLC-QTOF-MS/MS. The similarity and variation in chemical components and AGIs profile were evaluated by principle component analysis. The richest total phenolics, total flavonoids and hydrolysable tannins content was found in APT, ATB and AMM leaf extract, respectively. The IC50 values of α-glucosidase inhibition in vitro were 167–433 fold of that of acarbose. In total, 80 compounds were identified, among which 48, 51, 41 and 32 compounds were proposed from APT, ATB, AMM and ABM leaf extract, respectively. A total of 39 potent AGIs including 28 flavonoids, 6 tannins, 2 phenolic acids and 3 others were screened. Glucosides of kaempferol, myricetin, quercetin and apigenin constituted the predominant AGIs. The major phytochemical and AGIs profiles of APT and ATB leaf extract were similar, but they distinguished greatly among AMM, ABM and APT/ATB extracts. Flavonoids were the predominant chemical components and AGIs of the four tested Acer species, tannins come to the second. This study can provide important chemical information for the application of APT, ATB, AMM and ABM leaf in health food and pharmaceutical industry, specially as an new source of natural AGIs.
Background: Native Americans have had a rich ethnobotanical heritage for treating diseases, ailments, and injuries. Cherokee traditional medicine has provided numerous aromatic and medicinal plants that not only were used by the Cherokee people, but were also adopted for use by European settlers in North America. Methods: The aim of this review was to examine the Cherokee ethnobotanical literature and the published phytochemical investigations on Cherokee medicinal plants and to correlate phytochemical constituents with traditional uses and biological activities. Results: Several Cherokee medicinal plants are still in use today as herbal medicines, including, for example, yarrow (Achillea millefolium), black cohosh (Cimicifuga racemosa), American ginseng (Panax quinquefolius), and blue skullcap (Scutellaria lateriflora). This review presents a summary of the traditional uses, phytochemical constituents, and biological activities of Cherokee aromatic and medicinal plants. Conclusions: The list is not complete, however, as there is still much work needed in phytochemical investigation and pharmacological evaluation of many traditional herbal medicines.
The onion (Allium cepa L.) has been cultivated for thousands of years and is an important component of human diet. Recent studies suggest that onion can be used to reduce or prevent health problems such as asthma, cardiovascular diseases and diabetes due to its high antioxidant effect. Extract aqueous and ethanolic from three (purple, yellow and white) varieties of onion were studied for their total phenolic content, capacity and inhibitory activity against α-glucosidase and α- amylase. The total phenolic content varied between 6.59 to 9.25 mg/100 g and 24.3 a 42.7 mg/100 g the antioxidant capacity expressed as the percentage of inhibition of DPPH- radical ranged from 46.8 to 89.2% and 20.4% to 39.6% for ethanolic and aqueous extracts respectively. All ethanolic extracts showed capacity of inhibition for α-glucosidase y α-amylase from 58% to 34% and 33% to 22% respective while the aqueous extracts showed less effectiveness. Among the extracts, ethanolic extract of purple onion have the maximum concentration of total phenolic compounds, the highest antiradical capacity and α-glucosidase inhibition. Differences in free-radical scavenging and inhibition appeared to be dependent on the unique profile of phenolic compounds in each variety.
Background:
Worldwide, Type 2 diabetes has become a growing health problem. While many research articles in the field of ethnopharmacology have focused on the antidiabetic properties of medicinal plant species, insufficient evidence remains regarding their therapeutic use. Studies using both in vitro and in vivo models are necessary to evaluate various medicinal plants species, used in folk medicine, by using scientific criteria.
Methods:
This review focuses on isolated compounds from medicinal plant species that have reported antidiabetic activity in diabetes models. Searches using MEDLINE/PUBMED and SCOPUS databases were conducted to find articles in English on compounds isolated from plant species that have been tested using in vivo and/or in vitro diabetes models and published between 01/01/2005 and 12/31/2015.
Results:
The majority of studies involved in vitro assays that used the analysis of enzymes and receptors to investigate the antidiabetic mechanisms of active compounds at the molecular level. Compounds that have been reported to have important anti-diabetic activity with defined mechanisms were identified, including quercetin, oleanolic acid, kaempferol, ursolic acid, rutin, β-sitosterol, and mangiferin.
Conclusion:
This review contributes to the field of ethnopharmacology and should impact the design of new strategies in the search of novel compounds for the treatment of diabetic conditions.
In the forest industry, bark is an abundant residue, predominantly converted into calorific energy. As the antioxidant potential of phenolic compounds from sugar maple (Acer saccharum Marsh.) and red maple (Acer rubrum L.) bark has previously been established, the present study focused on the hot-water extraction optimization of these barks. Several process parameters (maple species, temperature, duration, ratio bark/water, particle size) were thus studied and large disparities were found between the two species. Extraction yield, phenolic content, and antioxidant capacity of red maple extracts were several times higher than those of sugar maple extracts. Principal component analysis, applied to the selected best extraction conditions, identified 3–4 clusters depending on the maple species. These groups were sorted from the highest extraction yield and energy consumption combined with the lowest phenolic content and antioxidant capacity, to moderate extraction yield and energy consumption with the highest phenolic content and antioxidant capacity.
Derived from the genus maple (Acer), acertannins are a group of gallotannins which have a characteristic 1,5-anhydro-d-glucitol (1,5-AG) occupying the central core position in the tannic acid structure whose hydroxyl groups have one or more galloyl residues. We have synthesized all ten naturally-occurring acertannins and seven new acertannin derivatives from 1,5-AG. Side-by-side comparisons revealed that 2,4,6-tri-O-galloyl-1,5-AG 21 (maplexin E) and maplexin F 22 (2,3,6-tri-O-galloyl-1,5-AG) were good inhibitors of ceramidase (CDase). In contrast, the core anhydrosugar 1,5-AG 12 itself and 3′,4′,5′-trimethoxy benzoyl derivatives 23–25 did not show CDase inhibition. Metabolic labelling experiments using NBD-hexanoic acid revealed that 50 μM of 6-O-galloyl-1,5-AG 16 (Ginnalin B), 2,6-di-O-galloyl-1,5-AG 19 (Ginnalin A), and 4,6-di-O-galloyl-1,5-AG 4 increased intracellular NBD-labeled ceramide, by 2.3, 2.2, and 2.1-fold, respectively. It is noteworthy that these acertannins 16, 19, and 4 promoted ceramide synthase 3 (CERS3) gene expression. Acertannins, therefore, represent a new class of potential intracellular ceramide regulators exhibiting both CDase inhibition and ceramide synthase promotion.
This research aimed to compare the antihyperglycemic and antioxidant abilities, and to characterize the bioactive constituents of two _Acer palmatum_ cultivars, _Acer palmatum_ ‘_Atropurpureum_’ (APA) and _Acer palmatum_ Thunb (APT). Dry materials were respectively extracted with 70% and 90% methanol, followed by sequentially fractionation with ethyl acetate and _n_-butanol. The phytochemical profile of selected fraction was determined by using UPLC-QTOF-MS/MS. APT is a better source of natural antioxidants and _α-_glucosidase inhibitors than APA due to its higher total phenolic content (TPC), and stronger antioxidant and _α-_glucosidase inhibitory activities. The highest total phenolic and total flavonoid content were found in the ethyl acetate fraction (EAF) of 90% methanol extract of APT (468.49 mg GAE/g Extract) and 70% methanol extract of APA (142.60 mg QuE/g Extract), respectively. The EAF of 70% methanol extract of APT gave the strongest DPPH· scavenging ability, ABTS+· scavenging ability and _α-_glucosidase inhibitory, with the IC50 values of 7.06, 4.18 and 1.99 μg/mL, respectively. The latter two were much higher than that of individual positive control. HPLC analysis revealed similar phytochemical profiles of all EAFs. Twenty-five compounds, including 3 organic acids, 5 phenolic acids, 8 tannins, 7 flavonoids and 2 proanthocyanidins, were identified or tentatively identified from APT, with tannins and flavonoid glucosides as the major active compounds. The results indicated a strong potential of _Acer palmatum_ as a natural source of excellent antioxidants and antihyperglycemic compounds in the prevention and treatment of type II diabetes and its complication.
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 MALD-TOF mass spectroscopy, and the 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 AGEs 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 was 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 AGEs formation, supporting 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.
Sweet potato (Ipomoea batatas) leaf (SPL) is an underused commercial vegetable with considerable bio-activities. By means of DPPH scavenging ability and α-glucosidase inhibitory oriented isolation, 9 and 7 compounds were isolated and identified, respectively. Among them, trans-N-(p-coumaroyl)tyramine (1), trans-N-feruloyltyramine (2), cis-N-feruloyltyramine (3), 4,5-feruloylcourmaoylquinic acid (8), caffeic acid ethyl ester (10), 7-hydroxy-5-methoxycoumarin (11), 7,3′-dimethylquercetin (13) and indole-3-carboxaldehyde (15), were firstly identified from SPL, and four of them (1, 2, 3 and 10) were firstly identified from genus Ipomoea. Phenethyl cinnamides and 3,4,5-triCQA exhibited the strongest α-glucosidase inhibition, while 3,4,5-triCQA and diCQAs were the dominant antioxidants. Structure-activity relationship revealed that higher caffeoylation of quinic acid and lower methoxylation of flavonols resulted in stronger antioxidant activity, and methylation and cis-configuration structure of phenethyl cinnamides weaken the α-glucosidase inhibition. Aforementioned results could help to explain the antioxidant activity and anti-diabetic activity of SPL, and provide theoretical basis for its further application.
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.
At least 175 food plants and 52 beverage plants were gathered by Native Peoples in eastern Canada. Iroquoian agriculturalists of southern Ontario cultivated corn, beans, squash, tobacco, and sunflowers, and gathered the greatest variety of food plants. Southern and eastern Algonkian hunters and gatherers ate a wide variety of wild plant foods including fleshy fruits, nuts, greens, and underground parts. Little is known about the use of wild food plants by northern Cree and Naskapi.Nutritional data for gathered plants indicate that many of these species exceed conventional plant sources for vitamins and minerals. Vitamin A, vitamin C, calcium, iron, and fibre are particularly well represented in certain gathered plants. Some wild plant foods require special preparation or must be consumed in limited quantities because they contain toxic secondary metabolites.Over 400 plants are used in native medicine. Native medicine consists of rational and ritualistic components. Treatment of physical disorders, whose origin could be determined, was effective. At least 105 medicinal plants have a real effectiveness based on phytochemical constituents. Conifers were the most widely used group of plants in this category. Antibiotic monoterpenes, polyacetylenes and alkaloids, astringent tannins, and analgesic monoterpenes and salicylates are among the most rationally and widely used plant constituents.There is need for more research into nutritional constituents and pharmacological properties to assess the value and potential of plants used by Native People of eastern Canada.
A new compound, pycnalin (1), together with four known compounds, ginnalins A (2), B (3), C (4), and 3,6-di-O-galloyl-1,5-anhydro-D-glucitol (3,6-di-GAG) (5), were isolated from Acer pycnanthum. The structure of 1 was determined on the basis of 2D-NMR spectral data and synthesis of 1. Pycnalin (1) is the first 1,5-anhydro-D-mannitol linked to a gallic acid, while compounds 2-5 were 1,5-anhydro-D-glucitol linked to gallic acids. All compounds were tested in vitro for α-glucosidase inhibitory and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities. Pycnalin (1) exhibited moderate α-glucosidase inhibitory activity as well as free radical scavenging activity. Ginnalin A (2) and 3,6-di-GAG (5), which have two galloyl groups, exhibited potent α-glucosidase inhibition, compared to those of other compounds 1, 3, and 4 containing a galloyl group. These results suggest that α-glucosidase inhibition is influenced by the number of galloyl groups.
Examinations were made on the chemical structure of aceritannin (acertannin), an oligogalloylated, crystalline tannin, C20H20O13·2H2O, m.p. 164∼166°, [α]12D +20°(Me2CO and EtOH, each), which was first isolated by Perkin and Uyeda from the leaves of Acer Ginnala MAXIM. It has now been proved that aceritannin should be formulated as 3, 6-di-O-galloyl-1, 5-anhydro-D-glucitol, i.e., no other than 1-deoxy derivative of 3, 6-di-O-galloyl-D-glucopyranose, a compound first isolated by Freudenberg (Ber., 52, 1238 (1919)) as one of the partial hydrolysis products of chebulinic acid, and later, unequivocally synthesized by Schmidt and Schach (Ann., 571, 29(1951)).
Tannins of two Acer species were investigated. Basides acertannin (1), gallotannins 2 and 3, having three and four galloyl groups on their 1, 5-anhydro-D-glucitol cores, were obtained from the leaves of Acer ginnala. The estimation of their tanning activity by the RMBG (relative affinity to methylene blue based on the affinity of geraniin) determination method revealed that the tanning activities of 2 and 3 are high, while that of 1, which has only two galloyl groups, is low. Two isomers (2a and 2b) of 2, and three isomers (3a, 3b and 3c) of 3 were respectively separated from each other after methylation. Their structures, in which all of the acyl groups (galloyl group, digalloyl group and/or trigalloyl group) are linked exclusively to O-2 and O-6 of the 1, 5-anhydro-D-glucitol core, were assigned. Fractionation of the constituents of leaves of Acer saccharum afforded two ellagitannins, geranin (10) and davidiin (11), and also chlorogenic acid and quercitrin.
Acer ginnala: Aceraceae; 2,6-di-O-galloyl-1,5-anhydro-D-glucitol; acertannin: correction of
structure.
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.
Leaves of Acer rubrum L. afforded the novel 1-O-galloyl-α-l-rhamnose as well as 1-O-galloyl-β-d-glucose; gallic acid; methyl gallate; ethyl gallate; m-digallate and ethyl digallate. Their structures were established on the basis of spectral and chemical evidence.
Digital phase shifter is widely used to achieve space scanning in phased array antenna. The quantization error will produce for discontinuous phase shifting of digital phase shifter. This paper introduces an approximate formula, derived by adding sub-array virtual elements and using the principle of pattern multiplication, about beam pointing accuracy of uniform linear array in condition of phase quantification. And a compensation method for sub-array elements is put forward to make approximate formula after compensating better estimate the precise pointing error. Simulation results show the effectiveness and correctness of the compensation method.
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 107.9μg 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 103μg phenolics, respectively) than MS-EtOAC extract (IC50>187μg 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.
Maple sap consists of sucrose, glucose, phenolic compounds, primary amines, peptides, amino acids, protein and other organic acids. They are acidic because of the presence of several organic acids including oxalic, succinic, fumaric, malic, tartaric, citric and aconitic acids. They have small quantities of amino acids and contain minerals such as potassium and calcium but at very small concentrations. Maple sap also contains trace of magnesium, manganese, sodium, phosphorus, zinc and copper. On the one hand, maple syrup reaches 66-67 degress Brix and contains minerals including tin. When the syrup tastes bad, it is due to excess sodium leads and high amounts of amino acids.
An ethanolic extract of red maple (Acer rubrum L.) leaves (RME) applied to trembling aspen (Populus tremuloides Michx.) leaves reduced feeding in choice test assays with forest tent caterpillar larvae (Malacosoma disstria Hbn.) (FTC), whereas a trembling aspen foliage extract, similarly applied, stimulated feeding. Compounds isolated from the RME were gallic acid, methyl gallate, ethyl gallate, m-digallate, ethyl m-digallate, 1-O-galloyl--D-glucose, 1-O-galloyl--L-rhamnose, kaempferol 3-O--D-glucoside, kaempferol 3-O--D-galactoside, kaempferol 3-O--L-rhamnoside, kaempferol-3-O-rhamnoglucoside, quercetin 3-O--D-glucoside, quercetin 3-O--L-rhamnoside and quercetin 3-O-rhamnoglucoside, (–)-epicatechin, (+)-catechin and ellagic acid. All of the gallates, (–)-epicatechin, and kaempferol 3-O--L-rhamnoside deterred feeding on trembling aspen leaf disks when applied at 0.28 mg/cm2. The two digallates deterred feeding by 90% and were the most effective. HPLC analysis indicated that ethyl m-digallate is present in amounts 10–100 higher in RME (2.5–250 mg/g) than any other compound. Thus, ethyl m-digallate appears to be the major compound protecting red maple from feeding by FTC, with a minor contribution from other gallates.
The anti-hyperglycemic effects of the leaves of sugar maple, Acer saccharum and purification and identification of the active compound were investigated. Extracts of the leaves showed a potent inhibitory effect on α-glucosidase in both in vivo and in vitro experiments. In vitro enzyme-inhibitory assay-guided fractionation of the crude extract gave active compound, acertannin (2,6-di-O-galloyl-1,5-anhydro-d-glucitol) by spectroscopic analysis. This is the first report that acertannin from A. saccharum may be used in diabetes care.
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.
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.
The crude ethanol and water extracts of different red maple (Acer rubrum L.) tissues: whole branches (WB), wood of branches (BW), bark of branches (BB), stem bark (SB) and whole twigs (T), were examined in order to determine their phenolic contents as well as their radical scavenging capacities. The total phenols (TP), total extractable tanins (TET) and non-precipitable phenols (NPP), were determined by combination of spectrophotometric and precipitation methods, while total flavonoids, hydroxy cinanmic acids and proanthocyanidins were determined spectrophotometrically. The radical scavenging activities of the extracts were determined against five reactive oxygen species (ROS): superoxide anion (O(2)(·-)), hydroxyl radical (HO(·)), peroxyl radical (ROO(·)), hypochlorite ion (ClO(-)), and hydrogen peroxide (H(2)O(2)) and one reactive nitrogen species (RNS): nitric oxide (NO). The extracts of stem bark were significantly more efficient (exhibiting the highest antioxidant efficiencies, AE) than the other studied extracts against all ROS (at p<0.05, Duncan statistical tests), except against NO. The correlation coefficients determined between total phenolic (TP) content and antiradical efficiencies were R(2)=0.12 for O(2)(·-); R(2)=0.29 for HO(·); R(2)=0.40 for H(2)O(2); R(2)=0.86 for ROO(·); R(2)=0.03 for NO(·) and R(2)=0.73 for ClO(-). Our results indicate potential utilisation of extracts as natural antioxidants.
Maple syrup is made by boiling the sap collected from certain maple ( Acer ) species. During this process, phytochemicals naturally present in tree sap are concentrated in maple syrup. Twenty-three phytochemicals from a butanol extract of Canadian maple syrup (MS-BuOH) had previously been reported; this paper reports the isolation and identification of 30 additional compounds (1-30) from its ethyl acetate extract (MS-EtOAc) not previously reported from MS-BuOH. Of these, 4 compounds are new (1-3, 18) and 20 compounds (4-7, 10-12, 14-17, 19, 20, 22-24, 26, and 28-30) are being reported from maple syrup for the first time. The new compounds include 3 lignans and 1 phenylpropanoid: 5-(3″,4″-dimethoxyphenyl)-3-hydroxy-3-(4'-hydroxy-3'-methoxybenzyl)-4-(hydroxymethyl)dihydrofuran-2-one (1), (erythro,erythro)-1-[4-[2-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-1-(hydroxymethyl)ethoxy]-3,5-dimethoxyphenyl]-1,2,3-propanetriol (2), (erythro,threo)-1-[4-[2-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-1-(hydroxymethyl)ethoxy]-3,5-dimethoxyphenyl]-1,2,3-propanetriol (3), and 2,3-dihydroxy-1-(3,4- dihydroxyphenyl)-1-propanone (18), respectively. In addition, 25 other phenolic compounds were isolated including (threo,erythro)-1-[4-[(2-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-1-(hydroxymethyl)ethoxy]-3-methoxyphenyl]-1,2,3-propanetriol (4), (threo,threo)-1-[4-[(2-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-1-(hydroxymethyl)ethoxy]-3-methoxyphenyl]-1,2,3-propanetriol (5), threo-guaiacylglycerol-β-O-4'-dihydroconiferyl alcohol (6), erythro-1-(4-hydroxy-3-methoxyphenyl)-2-[4-(3-hydroxypropyl)-2,6-dimethoxyphenoxy]-1,3-propanediol (7), 2-[4-[2,3-dihydro-3-(hydroxymethyl)-5-(3-hydroxypropyl)-7-methoxy-2-benzofuranyl]-2,6-dimethoxyphenoxy]-1-(4-hydroxy-3-methoxyphenyl)-1,3-propanediol (8), acernikol (9), leptolepisol D (10), buddlenol E (11), (1S,2R)-2-[2,6-dimethoxy-4-[(1S,3aR,4S,6aR)-tetrahydro-4-(4-hydroxy-3,5-dimethoxyphenyl)-1H,3H-furo[3,4-c]furan-1-yl]phenoxy]-1-(4-hydroxy-3-methoxyphenyl)-1,3-propanediol (12), syringaresinol (13), isolariciresinol (14), icariside E4 (15), sakuraresinol (16), 1,2-diguaiacyl-1,3-propanediol (17), 2,3-dihydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl)-1-propanone (19), 3-hydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl)propan-1-one (20), dihydroconiferyl alcohol (21), 4-acetylcatechol (22), 3',4',5'-trihydroxyacetophenone (23), 3,4-dihydroxy-2-methylbenzaldehyde (24), protocatechuic acid (25), 4-(dimethoxymethyl)pyrocatechol (26), tyrosol (27), isofraxidin (28), and 4-hydroxycatechol (29). One sesquiterpene, phaseic acid (30), which is a known metabolite of the phytohormone abscisic acid, was also isolated from MS-EtOAc. The antioxidant activities of MS-EtOAc (IC(50) = 75.5 μg/mL) and the pure isolates (IC(50) ca. 68-3000 μM) were comparable to that of vitamin C (IC(50) = 40 μM) and the synthetic commercial antioxidant butylated hydroxytoluene (IC(50) = 3000 μM), in the diphenylpicrylhydrazyl radical scavenging assay. The current study advances scientific knowledge of maple syrup constituents and suggests that these diverse phytochemicals may impart potential health benefits to this natural sweetener.
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.
The aim of this study is to collate all available data on antidiabetic plants that inhibit alpha glucosidase, reported mainly by Medline (PubMed) these last years. In the present study, interest is focused on experimental researches conducted on hypoglycemic plants particularly those which show alpha glucosidase inhibitor activity alongside bioactive components. This study describes 47 species that belong to 29 families. The plant families, which enclose the species, studied most as inhibitors of alphaglucosidase, are Fabaceae (6 species.), Crassulaceae (3 species), Hippocrateacaea (3 species), Lamiaceae (3 species), and Myrtaceae (3 species), with most studied species being Salacia reticulata (Hippocrateaceae) and Morus alba (Moraceae). The study also covers natural products (active natural components and crude extracts) isolated from the medicinal plants which inhibit alpha glucosidase as reported this last decade. Many kinds of these isolated natural products show strong activity such as, Alkaloids, stilbenoids (polyphenol), triterpene, acids (chlorogenic acid, betulinic acid, syringic acid, vanillic acid, bartogenic acid, oleanolic acid, dehydrotrametenolic acid, corosolic acid, ellagic acid, ursolic acid, gallic acid), phytosterol, myoinositol, flavonoids, Flavonolignans, anthraquinones, anthrones, and xanthones, Feruloylglucosides, flavanone glucosides, acetophenone glucosides, glucopyranoside derivatives, genine derivatives, flavonol, anthocyanin and others.
To study the chemical constituents from the roots of Distylium myricoides.
The chemical constituents were isolated and separated with chromatographic techniques, and structures were identified by spectroscopic methods.
Eight phenolic compounds were isolated and identified as: 4-hydroxy-2-methoxyphenol 1-O-beta-D-(6'-O-galloyl) glucopyranoside (1), 4-hydroxy-3-methoxy-phenol 1-O-beta-D-(6'-O-galloyl) glucopyranoside (2), 3,4,5-tri methoxyphenol 1-O-beta-D-(6'-O-galloyl) glucopyranoside (3), 1,2,3,4,6-penta-O-galloyl-beta-D-glucopyranoside (4), methyl gallate (5), ethyl gallate (6), 3,4-dihydroxybenzoic acid (7), gallic acid (8).
All compounds were isolated from the genus Distylium for the first time.
The increased prevalence of type 2 diabetes mellitus is a major concern for health providers. We therefore assessed whether voglibose, an alpha-glucosidase inhibitor, could prevent the development of type 2 diabetes in high-risk Japanese individuals with impaired glucose tolerance.
1780 eligible patients on a standard diet and taking regular exercise with impaired glucose tolerance were randomly assigned to oral voglibose 0.2 mg three times a day (n=897) or placebo (n=883) in a multicentre, double-blind, parallel group trial. Treatment was continued until participants developed type 2 diabetes (primary endpoint) or normoglycaemia (secondary endpoint), or for a minimum of 3 years, subject to the findings of an interim analysis. Analysis was by full analysis set. This trial is registered with the University Hospital Medical Information Network (UMIN) clinical trials registry, number UMIN 000001109.
In the interim analysis, voglibose was better than placebo (p=0.0026) in individuals treated for an average of 48.1 weeks (SD 36.3). Patients treated with voglibose had a lower risk of progression to type 2 diabetes than did those on placebo (50 of 897 vs 106 of 881; hazard ratio 0.595, 95% CI 0.433-0.818; p=0.0014). More people in the voglibose group achieved normoglycaemia than did those in the placebo group (599 of 897 vs 454 of 881; 1.539, 1.357-1.746; p<0.0001). 810 (90%) of 897 patients in the voglibose group had adverse events versus 750 (85%) of 881 in the placebo group. Serious adverse events (all one each) in the voglibose group were cholecystitis, colonic polyp, rectal neoplasm, inguinal hernia, liver dysfunction, and subarachnoid haemorrhage, and in the placebo group were cerebral infarction and cholecystitis.
Voglibose, in addition to lifestyle modification, can reduce the development of type 2 diabetes in high-risk Japanese individuals with impaired glucose tolerance.
Takeda.
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