Trigalloyl Research Articles

Medicinal Plants and Bioactive Compounds with Potential Anti-inflammatory and Antidiabetic Activities: A Review

Background: Inflammation is a complex process. Persistent and uncontrolled inflammation may act as an etiologic factor for many chronic disorders like diabetes. Objective: This review aims to classify the anti-inflammatory and antidiabetic medicinal plants, their traditional uses, and their active compounds that have been tested for their anti-inflammatory and antidiabetic effects. Methods: We checked scientific publications in various electronic databases from 1981 to 2021. All the molecular structures were provided in ADC/ChemSketch. Results: We reviewed 58 species, belonging to 39 families. These species have long been used in traditional medicine to cure a variety of ailments, including, dysentery, typhoid fever, anemia, digestive and cardiac disorders, as well as diabetes and inflammation. Asteraceae represents the dominant family. The most potent anti-inflammatory and antidiabetic active compounds were reviewed including myricetin, quercetin, hesperetin, rutin, luteolin, chlorogenic acid, vanillic acid, gallic acid, ferulic acid, benzoic acid, cinnamic acid, gentisic acid, camphor, 1,8-cineol, p-cymene, limonene, linalool, thymoquinone, carvacrol, aromadendrine, α-pinene, lycopene, phytol, imperatorin, chalepin, hexadecanoic acid, linoleic acid, tellimagrandin I, and trigalloyl glucose. Conclusion: This review indicates that medicinal plants have many therapeutic dynamics against inflammation and diabetes that could be exploited for the discovery of therapeutic preparation or agent for treating the two illnesses at the same time.

Phytochemical analysis and biological activity of some local and imported walnut

To study the bioactive substances of the walnut kernel of six cultivars which were newly selected from Kurdistan-Iraq and one type import from America, analyzed for their phytochemical contents and antioxidant activities. HPLC (High-performance liquid chromatography) was used for phenolic compound estimation, GC (Gas chromatography) for fatty acid analysis, and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical-scavenging. In terms of fatty acids, palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid of all seven types we analyzed, all of them had a significant result. As for antioxidants, the same as before, the antioxidants were significant for all the chosen samples. In terms of phenolic compounds, quinic acid, gallic acid, 1,2,3,6 trigalloyl glucose, vanillic acid, syringic acid, and rutin, all types were significant as well. Finally, our results show that most of them were of high significance. Some regions in the Kurdistan region of Iraq showed high results for important secondary products, while the American counterpart is lower but still better than some of the Kurdistan region walnuts

LC-MS based metabolomics and sensory evaluation reveal the critical compounds of different grades of Huangshan Maofeng green tea

Six grades of Huangshan Maofeng (HSMF) green tea were studied by LC-MS based metabolomics combined with sensory evaluation on bitterness, astringency and sweet aftertaste. Although there was no significant correlation (p > 0.05) between tea grades and the contents of total polyphenols and flavonoids, non-targeted metabolomics revealed that all grades of tea could be classified into two groups, group 1 (T1, T2) and group 2 (T3, 1, 2, 3). The main marker compounds responsible for distinguishing the two groups were procyanidins, flavonoid glycosides, and four hydrolysable tannins, including monogalloyl glucose, digalloyl glucose, trigalloyl glucose and galloyl-hexahydroxydiphenoyl-glucose. The Pearson correlation coefficients of these hydrolysable tannins with HSMF green tea grades were between 0.82 and 0.95. Furthermore, their Pearson correlation coefficients regarding sweet aftertaste were in the range of 0.73–0.83. This study suggested combination of metabolomics and sensory evaluation could provide an insight in searching for more potential taste-active components.

Phytochemical bioaccessibility and in vitro antidiabetic effects of Chinese sumac (Rhus chinensis Mill.) fruits after a simulated digestion: insights into the mechanisms with molecular docking analysis

AbstractThis work studied the effects of gastrointestinal digestion on the phytochemical bioaccessibility and in vitro anti‐diabetic effects of different fractions from Chinese sumac fruits and delineated the underlying mechanisms by molecular docking. Results showed that gastric digestion significantly increased the phytochemical bioaccessibility and inhibitions for α‐glucosidase, dipeptidyl peptidase‐4 (DPP‐IV) and advanced glycation end product (AGE) formation of the ethanol‐extracted fraction, whereas intestinal digestion remarkably decreased these parameters (P < 0.05). For the free phenolic fraction, the parameters were remarkably reduced after gastric digestion but significantly increased after intestinal digestion (P < 0.05). Quercitrin and gvajaverin contributed the most to the α‐glucosidase and DPP‐IV inhibitions, and trigalloyl glucose and its isomer could be the primary bioactive substance responsible for AGE suppression. Quercitrin, the predominant phenolic compound, could effectively interact with crucial amino acid residues in α‐glucosidase, DPP‐IV and bovine serum albumin with hydrogen bonds and hydrophobic interactions to exert its inhibitions.

HPLC/MS-MS Identification of Oak Quercus aegilops Root Tannins

Tannins are natural polyphenolic compounds widely distributed in the plant kingdom in the leaves, bark, fruits, and other parts. They have various biological functions in humans and animals and are used mainly in the pharmaceutical and cosmetic industries. The aim of this work was to isolate, extract, purify, and identify the tannins from the root bark of a common oak tree (Quercus aegilops L.) in Jordan and around the Mediterranean. The results showed that at least one form of ellagitannin (ellagic acid ester), quercitrin, afzelechin, valoneic acid, trigalloyl glucose, and catechin was identified in addition to two unidentified compounds. Results of this work can help in developing an ESI MS/MS search library for the constituents of the tannins of oak (Quercus aegilops L.) root bark.

HPLC-DAD-Q-ToF-MS profiling of phenolic compounds from mango (Mangifera indica L.) seed kernel of different cultivars and maturation stages as a preliminary approach to determine functional and nutraceutical value

Mango seed kernel is a by-product which is usually discarded. However, it has been confirmed in this study that seed kernel exhibits more phenolic compounds with bioactive properties than edible fraction of mango. The influence of factors such as cultivar and maturation degree on the phenolic composition has been studied to evaluate nutraceutical value. The comprehensive analysis of phenolic composition by HPLC-DAD-Q-ToF-MS seed kernel from different cultivars (‘Keitt’, ‘Kent’and ‘Osteen’) at five maturation stages was conducted. Results evidenced that ‘Keitt’ samples exhibited higher quantities of iriflophenone glucoside, maclurin C-glucoside, maclurin digalloyl glucoside, mangiferin, 5-galloyl quinic acid and trigalloyl glucose at the first three ripening stages. However, seed kernel from ‘Osteen’ variety showed higher amounts of hexa- and hepta-gallotannins whose concentrations diminished over the maturation course. Therefore, cultivar and maturation stage factors should be take into account due to their influence on the phenolic composition and subsequently on the nutraceutical value.

Partial purification and characterization of a thermostable mushroom tannase induced during solid state fermentation of Toxicodendron vernicifluum stem bark by Fomitella fraxinea

A thermostable extracellular tannase induced during solid state fermentation of the stem bark of Toxicodendron vernicifluum (Stokes) F.A. Barkley (Anacardiaceae) with Fomitella fraxinea was homogeneously isolated through ammonium sulfate precipitation and purified by DEAE-cellulose, and Sephadex G‒100 gel chromatography. It was then characterized for optimal reaction temperature and pH, thermal and pH stability, effects of metal ions as well as its hydrolysis patterns using 1,2,3,4,6-penta-O-galloyl-β-d-glucose (PGG) as a substrate. The enzyme was purified 103.9-fold with 2.92% recovery and a single protein band corresponding to it was observed at 44.9 kDa during SDS-PAGE analysis. Optimal temperature and pH were found to be 50–70 °C and 5.5, respectively. This enzyme was substantially stable at temperatures below 70 °C and pH values between 5.0 and 7.0. Its activity was inhibited by Fe2+ ion (66%) and Cu2+ (39%) at a concentration of 5 mM. It also showed a different hydrolysis pattern from that of commercial Aspergillus oryzae tannase when PGG was used as a substrate. The tannase purified from the fermented plant material in this study unusually produced oligomeric galloylglucoses such as digalloylglucose (DGG), trigalloylglucose (TGG) and tetragalloylglucose (TeGG) from PGG while the Asp. oryzae tannase produced gallic acid and methyl gallate as final products. Therefore, this enzyme can be more preferably applied for production of bioactive oligomeric galloylglucoses such as DGG, TGG and TeGG from PGG or tannic acid.

Inhibitory effects of extracts from Moutan Cortex on formation of advanced glycation end-products (AGEs) in vitro and specificity screening of its potential active components

In this study, bovine serum albumin (BSA)/methylglyoxal (MGO) non-enzymatic glycosylation reaction system was used for the evaluation of the inhibitory effects of Moutan Cortex extracts on the formation of AGEs. The HPLC-LC-ESI-MS/MS technology was adopted to test and indentify active components in Moutan Cortex against AGEs formation. The different concentrations of extracts (crude herb concentration 50, 100, 150, 200, 250 g•L⁻¹) from Moutan Cortexwas determined by fluorospectrophotometry, indicating an activity against AGEs formation in different concentrations of extracts, the inhibition ratio were (36.2±5.3)%, (43.5±6.2)%, (55.4±7.8)%, (68.6±6.7)%, (70.4±8.2)%, respectively after 6-day reaction in a dose dependent manner. Besides, the forming speed of AGEs tended to be steady after 24 h reaction. The HPLC technology was used to analyze chromatograms before and after the incubation of Moutan Cortex and methylglyoxal, identify changes in five chromatographic peaks and show decrease or increase in chromatographic peaks. These substances were trigalloyl glucose, tetragalloyl glucose, galloylpaeoniflorin, hexagalloyl glucose and benzoylpaeoniflorin after LC-ESI-MS/MS identification. Extracts from Moutan Cortex showed the remarkable inhibitory effects against formation of AGEs in BSA/glucose system. Furthermore, these potential active components might be associated with the efficacy of Moutan Cortex on treatment of diabetic nephropathy, which enriches basic studies for Moutan Cortex and provides ideas and reference basis for subsequent studies.

Production profiles of phenolics from fungal tannic acid biodegradation in submerged and solid-state fermentation

Potent antioxidant phenolics are derived from tannin biodegradation. Understanding of biodegradation pathways through the identification of the intermediates molecules of great value like tannins is important to pursuit the production of bioactive monomers. Biodegradation of tannins remains poorly understood due to their chemical complexity and reactivity. Tannic acid biodegradation by Aspergillus niger GH1 in submerged fermentation (SF) and solid state fermentation (SSF) was evaluated by liquid chromatography coupled to mass spectrometry (LC–MS). Both cultures were kinetically monitored for the biodegradation profiles during 72h. Differences in tannic acid composition were evidenced and the consumption of substrate and identification of biodegradation intermediates were achieved. The mechanism of tannic acid degradation by A. niger GH1 is by degradation of high molecular weight gallotannins and highly polymerized tannins to small molecules like gallic acid, digalloyl glucose and trigalloyl glucose. Important differences on time of substrate uptake and product release were revealed.

Simple solution for a complex problem: Proanthocyanidins, galloyl glucoses and ellagitannins fit on a single calibration curve in high performance-gel permeation chromatography

This study was undertaken to explore gel permeation chromatography (GPC) for estimating molecular weights of proanthocyanidin fractions isolated from sainfoin ( Onobrychis viciifolia). The results were compared with data obtained by thiolytic degradation of the same fractions. Polystyrene, polyethylene glycol and polymethyl methacrylate standards were not suitable for estimating the molecular weights of underivatized proanthocyanidins. Therefore, a novel HPLC–GPC method was developed based on two serially connected PolarGel-L columns using DMF that contained 5% water, 1% acetic acid and 0.15 M LiBr at 0.7 ml/min and 50 °C. This yielded a single calibration curve for galloyl glucoses (trigalloyl glucose, pentagalloyl glucose), ellagitannins (pedunculagin, vescalagin, punicalagin, oenothein B, gemin A), proanthocyanidins (procyanidin B2, cinnamtannin B1), and several other polyphenols (catechin, epicatechin gallate, epicallocatechin gallate, amentoflavone). These GPC predicted molecular weights represented a considerable advance over previously reported HPLC–GPC methods for underivatized proanthocyanidins.

White and green tea polyphenols inhibit pancreatic lipase in vitro

Abstract Green, white and black teas were assayed for inhibition of pancreatic lipase activity in vitro. White tea proved to be more effective than green tea with black tea showing little inhibition even at 200 μg GAE/ml. The EC50 values for inhibition were 22 μg/ml for white tea and 35 μg/ml for green tea; both easily achievable from normal infusions of tea. Liquid chromatography-mass spectroscopy analysis showed that white and green teas had essentially equal amounts of flavan-3-ols but green tea had higher levels of flavonols. White tea had higher levels of 5-galloyl quinic acid, digalloyl glucose, trigalloyl glucose and the tannin, strictinin. After chromatography on Sephadex LH-20, the main inhibitory fraction was enriched in strictinin and fractions enriched in other components were ineffective. This suggests that strictinin content may be crucial for inhibition of pancreatic lipase. However, the possibility of synergies between the polyphenols cannot be disregarded.

470 POSTER Target identification permits rational development of the prodrug GMX1777 for the treatment of melanoma

This study was undertaken to explore gel permeation chromatography (GPC) for estimating molecular weights of proanthocyanidin fractions isolated from sainfoin (Onobrychis viciifolia). The results were compared with data obtained by thiolytic degradation of the same fractions. Polystyrene, polyethylene glycol and polymethyl methacrylate standards were not suitable for estimating the molecular weights of underivatized proanthocyanidins. Therefore, a novel HPLC–GPC method was developed based on two serially connected PolarGel-L columns using DMF that contained 5% water, 1% acetic acid and 0.15 M LiBr at 0.7 ml/min and 50 °C. This yielded a single calibration curve for galloyl glucoses (trigalloyl glucose, pentagalloyl glucose), ellagitannins (pedunculagin, vescalagin, punicalagin, oenothein B, gemin A), proanthocyanidins (procyanidin B2, cinnamtannin B1), and several other polyphenols (catechin, epicatechin gallate, epicallocatechin gallate, amentoflavone). These GPC predicted molecular weights represented a considerable advance over previously reported HPLC–GPC methods for underivatized proanthocyanidins.

Understanding the Native Californian Diet: Identification of Condensed and Hydrolyzable Tannins in Tanoak Acorns (Lithocarpus densiflorus)

The tanoak (Lithocarpus densiflorus) acorn was a staple food in the Native American diet and is still used in traditional dishes. Acorns from the genus Quercus have been shown to contain a large range of hydrolyzable tannins. However, neither hydrolyzable nor condensed tannins have been characterized in tanoak acorns. The aim of this study was to identify the full range of hydrolyzable and condensed tannins in extracts of tanoak acorns using liquid chromatography/electrospray ionization-mass spectrometry/mass spectrometry. Condensed tannins were identified as B type oligomers of (epi)-catechin (procyanidins) with a degree of polymerization up to six. Oligomers up to and including tetramers were identified by UV spectra and MS detection whereas pentamers and hexamers were detected only by MS. The total concentration of condensed tannins was 464 mg/100 g acorn pericarp. The concentration of propocyanidin monomers, dimers, trimers, and tetramers in acorn pericarp (mg/100 g acorn pericarp) were 95 +/- 10.9, 148 +/- 35.0, 90 +/- 17.9, and 131 +/- 1.9, respectively. No procyanidins were found in the acorn cotyledon tissue. A total of 22 hydrolyzable tannins were identified in methanolic extracts of acorn cotyledon tissue. Gallic acid derivatives predominated and included galloylated esters of glucose, hexahydrodiphenoyl esters of glucose, and methylated gallates. Galloylated esters of glucose were present as isomers of galloyl glucose, digalloyl glucose, and trigalloyl glucose. Mass spectral fragmentation patterns indicate the presence of one gallic acid-galloyl glucose isomer and two gallic acid-digalloyl-glucose isomers. No isomers of tetragalloyl glucose and pentagalloyl glucose were identified. Ellagic acid and ellagic acid pentoside were also identified.

Decreased polyphenol transport across cultured intestinal cells by a salivary proline-rich protein

Tannins are polyphenols commonly found in plant-derived foods. When ingested they can have various harmful effects, but salivary proline-rich proteins (PRPs) may provide protection against dietary tannins. The aim of this study was to investigate whether basic PRPs, a major family of salivary proteins, can prevent intestinal absorption of tannin. To do so it was necessary first to characterize transport of pentagalloyl glucose (5GG), a hydrolysable tannin, across cultured epithelial cells. Using human intestinal epithelial cells (Caco-2 cells) it was found that a partial degradation of 5GG occurred during transepithelial transport resulting in the presence of 5GG as well as tetra- and trigalloyl glucose and glucose in the receiving compartment. The sodium-dependent glucose transporter SGLT1 played a role in apical (mucosal) to basolateral (serosal) transport and transport in the opposite direction was dependent on the multidrug resistance-associated protein MRP2. An increased uptake from the apical compartment was seen when the basolateral receiving solution was human serum rather than a balanced salt solution. Transport both in apical–basolateral and basolateral–apical directions was reduced when 1B4, a human basic PRP, was added to the 5GG-containing medium. This decrease closely paralleled the formation of insoluble 5GG–1B4 complexes. It appears that the formation of insoluble tannin–protein complexes diminishes the uptake of 5GG and its metabolites. There is little evidence of other biological activities of basic PRPs so in contrast to other salivary proteins they may exert a biological function in the intestines.

A theoretical study of the interactions of water with gallic acid and a PEO/TGG complex

PM3 Semi-empirical molecular orbital calculations on the interaction of water and gallic acid (GA) show the hydrophilic part of the solute (GA) to form strong directional bonds to 5 H2O molecules. To form a monolayer around GA, containing trigalloyl glucose both hydrophilic and hydrophobic regions, requires about 43 H2O molecules. PM3, MM and MD calculations on complexes between the hexamer of poly(ethylene oxide) (PEO)6 and cofactor containing trigalloyl glucose (TGG) show that (PEO)6/TGG complexes do not form in aqueous solution, which agrees with the experimental results in pure water, in the absence of salt, obtained with PEO and corilagin, a very similar molecule. It is possible that a (PEO) conformers, with the oxygens outside, are favoured in aqueous solution, because the H2O molecules can more easily hydrogen bond with the PEO ether oxygens. A distinct change in the rate of change of the relative total energy per H2O molecule occurs at 10 H2O molecules: beyond 10 H2O molecules a slow varying plateau is observed to and beyond 120 H2O molecules. This is critical when calculating the enthalpy of association of a solvated molecular complex.

Analysis of oak tannins by liquid chromatography-electrospray ionisation mass spectrometry

Extractable tannins were analysed by liquid chromatography-electrospray ionisation mass spectrometry in two oak species, North American white oak ( Quercus alba) and European red oak ( Quercus robur). They mainly included various glucose gallic and ellagic acid esters. The structures were partially determined, and they included grandinin/roburin E, castalagin/vescalagin, gallic acid, valoneic acid bilactone, monogalloyl glucose, digalloyl glucose, trigalloyl glucose, ellagic acid rhamnose, quercitrin and ellagic acid.

Tannin interactions with a full-length human salivary proline-rich protein display a stronger affinity than with single proline-rich repeats

The protein IB5 has been purified from human parotid saliva. This protein contains several repeats of a short proline-rich sequence. Dissociation constants have been measured at several discrete binding sites using 1H-NMR for the hydrolysable tannins (polyphenols) ( β-1,3,6- tri-O- galloyl- d-glucopyranose , β-1,2,4,6- tetra-O- galloyl- d-glucopyranose and β-1,2,3,4,6- penta-O- galloyl- d-glucopyranose and the condensed proanthocyanidin (−)-epicatechin. The dissociation constants for trigalloyl glucose and pentagalloyl glucose were 15 × 10 −5 and 1.7 × 10 −5 M, respectively, which are 115 and 1660 times stronger than those previously measured under the same conditions for a single repeat of a mouse salivary proline-rich protein. The increase in affinity is ascribed to intramolecular secondary interactions, which are strengthened by the rigidity of the interacting molecules.