RESUMO
Ellagic acid (EA) is a bioactive polyphenolic compound naturally occurring as secondary metabolite in many plant taxa. EA content is considerable in pomegranate (Punica granatum L.) and in wood and bark of some tree species. Structurally, EA is a dilactone of hexahydroxydiphenic acid (HHDP), a dimeric gallic acid derivative, produced mainly by hydrolysis of ellagitannins, a widely distributed group of secondary metabolites. EA is attracting attention due to its antioxidant, anti-inflammatory, antimutagenic, and antiproliferative properties. EA displayed pharmacological effects in various in vitro and in vivo model systems. Furthermore, EA has also been well documented for its antiallergic, antiatherosclerotic, cardioprotective, hepatoprotective, nephroprotective, and neuroprotective properties. This review reports on the health-promoting effects of EA, along with possible mechanisms of its action in maintaining the health status, by summarizing the literature related to the therapeutic potential of this polyphenolic in the treatment of several human diseases.
Assuntos
Antialérgicos/farmacologia , Anti-Inflamatórios/farmacologia , Antineoplásicos/farmacologia , Ácido Elágico/farmacologia , Taninos Hidrolisáveis/farmacologia , Hipoglicemiantes/farmacologia , Extratos Vegetais/farmacologia , Polifenóis/farmacologia , Substâncias Protetoras/farmacologia , Animais , Antialérgicos/metabolismo , Anti-Inflamatórios/metabolismo , Antineoplásicos/metabolismo , Ácido Elágico/metabolismo , Frutas/química , Frutas/metabolismo , Trato Gastrointestinal/metabolismo , Humanos , Taninos Hidrolisáveis/química , Taninos Hidrolisáveis/metabolismo , Hipoglicemiantes/metabolismo , Fitoterapia/métodos , Extratos Vegetais/metabolismo , Plantas/química , Plantas/metabolismo , Polifenóis/metabolismo , Substâncias Protetoras/metabolismoRESUMO
The role and mechanism of elagitannase is misunderstood because it exhibited different activities due to the low purity or complexity of substrates, and there is no available information about the biochemical, physicochemical and molecular characteristics of the enzyme. This study was aimed to obtain enzymatic extracts by Aspergillus niger GH1 in solid-state fermentation, using dextrose and ellagitannins as inducers of ellagitannase. Protein and bioinformatic analysis were performed to identify the protein sequence expressed in terms of culture conditions. The presence of ellagitannins increased ellagitannase activity 1143-fold compared to dextrose. The higher ellagitannase activity was found at 18 h of culture (1143.30 U g-1PE). Three groups of proteins were identified in both cultures: ß-glucosidase, phospholipase C, and triacylglycerol lipase. However, only phospholipase C was overexpressed with ellagitannins as inducers, showing the most spontaneous reaction with punicalagin (ΔG -8.56). These results suggest that phospholipase could be involved in ellagitannins biosynthesis.
Assuntos
Ácido Elágico , Taninos Hidrolisáveis , Aspergillus niger/metabolismo , Fermentação , Taninos Hidrolisáveis/metabolismoRESUMO
Amylases are interesting targets for antidiabetic drugs because their inhibition is able to lower glycaemia without the need of hormonal control, as promoted by insulin or glibenclamide. In this context, the comparison between the binding features of α-amylases with their substrate and known inhibitors may provide insights aiming at the discovery of new antidiabetic drugs. In this work, the structure of the porcine pancreatic α-amylase was modelled with the acarbose pentasaccharide inhibitor, and used in structure-based virtual screening simulations based on a library containing the structures of amylose (AMY), acarbose (ACA) and the more representative structures of condensed tannin (CTN) and hydrolysable tannin (HTN). After validation of the methodology by redocking (mean rmsd ~ 0.8 Å), the scores provided by programs AutoDock/Molegro were contradictory (- 1.5/- 23.3; - 3.5/- 24.6; - 4.3/- 14.6; -/- 19.5 for AMY, ACA, CTN and HTN respectively), indicating that a more sensitive methodology was necessary. The ΔGbinding was calculated by the molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) method, which indicated that the HTN, ACA and CTN had higher affinities for the enzyme regarding the AMY substrate, with values of - 350.0, - 346.2, - 320.5 and - 209.2 kJ mol-1, respectively. The predicted relative affinities of HTN and CTN are in agreement with those obtained experimentally. The results provided useful information for the characterization of tannin binding to α-amylase, which can be applied in future studies aiming at finding new hypoglycaemic molecules among natural products.
Assuntos
Inibidores Enzimáticos/farmacologia , Taninos Hidrolisáveis/farmacologia , Simulação de Dinâmica Molecular , alfa-Amilases Pancreáticas/antagonistas & inibidores , Animais , Inibidores Enzimáticos/metabolismo , Taninos Hidrolisáveis/metabolismo , Hipoglicemiantes/farmacologia , alfa-Amilases Pancreáticas/metabolismo , Ligação Proteica , Sus scrofa/metabolismoRESUMO
Plant defenses against herbivores are predicted to evolve to be greater in warmer climates, such as lower latitudes where herbivore pressure is also thought to be higher. Instead, recent findings are often inconsistent with this expectation, suggesting alternative hypotheses are needed. We tested for latitudinal gradients in plant defense evolution at the macroevolutionary scale by characterizing plant chemical defenses across 80 species of the evening primroses, spanning both North and South America. We quantified phenolics in leaves, flowers, and fruits, using advanced analytical chemistry techniques. Dominant individual ellagitannin compounds, total concentrations of ellagitannins, flavonoids, total phenolics, and compound diversity were quantified. Variation in these compounds was predicted with latitude, temperature, precipitation, and continent using phylogenetic generalized least squares (PGLS) multiple regression models. Latitude did not strongly explain variation in chemical defenses. Instead, fruit total ellagitannins, oenothein A, and total phenolics were greater in species inhabiting regions with colder climates. Using analytical chemistry and 80 species in two continents, we show that contrary to classic predictions, concentrations of secondary metabolites are not greater at lower latitudes or in warmer regions. We propose higher herbivore pressure in colder climates and gradients in resource availability as potential drivers of the observed patterns in Oenothera.
Assuntos
Antibiose , Evolução Biológica , Flavonoides/metabolismo , Taninos Hidrolisáveis/metabolismo , Oenothera/fisiologia , Fenóis/metabolismo , Clima , Flores/química , Frutas/química , América do Norte , Folhas de Planta/química , América do SulRESUMO
The ellagitannins are a group of phenolic compounds with biological activities. Ellagic acid is the product obtained from hydrolysis of ellagitannins. Information related to the biosynthesis of ellagitannins still been scarce and confused. The ellagitannins are obtained from plants and their purification process implies mainly the use of chromatographic techniques. The ellagitannin acyl hydrolase (EAH) also known as ellagitannase is an enzyme capable of hydrolyzing the ester bonds of ellagitannins and the consequent releasing of ellagic acid. Information about the EAH is not clear because the enzyme had showed different activities due to the low purity or complexity of substrates and there is no available information about the biochemical, physicochemical and molecular characteristics of EAH. The present review describes information related to the sources, biosynthesis and the purification of ellagitannins and a current assessment on the production of ellagitannase.
Assuntos
Taninos Hidrolisáveis/metabolismo , Aspergillus niger/metabolismo , Disponibilidade Biológica , Cromatografia Líquida de Alta Pressão , Ácido Elágico/química , Ácido Elágico/metabolismo , Hidrolases/metabolismo , Taninos Hidrolisáveis/química , Taninos Hidrolisáveis/isolamento & purificaçãoRESUMO
Geopropolis is a mixture of plant resins, waxes, and soil produced by the stingless bee Melipona fasciculata Smith. This paper describes the antioxidant activity and chemical composition of geopropolis produced by M. fasciculata. The total phenolic content determined with the Folin-Ciocalteu reagent was highest in the ethyl acetate fraction and hydroalcoholic extract. Antioxidant activity was assayed by the in vitro DPPH, ABTS, and FRAP assays. The hydroalcoholic extract and fractions of geopropolis, except for the hexane fraction, exhibited antioxidant activity against DPPH, ABTS, and FRAP. The phenolic compounds were identified by HPLC-DAD-MS on the basis of the evaluation of their UV-vis absorption maxima (λmax) and mass spectral analysis. Eleven compounds belonging to the classes of phenolic acids and hydrolyzable tannins (gallotannins and ellagitannins) were tentatively identified. These compounds are responsible for the antioxidant activity and high phenolic content of geopropolis produced by M. fasciculata.
Assuntos
Antioxidantes/análise , Abelhas/metabolismo , Taninos Hidrolisáveis/análise , Hidroxibenzoatos/análise , Própole/química , Animais , Antioxidantes/metabolismo , Abelhas/química , Cromatografia Líquida de Alta Pressão , Taninos Hidrolisáveis/metabolismo , Hidroxibenzoatos/metabolismo , Espectrometria de Massas , Própole/metabolismoRESUMO
In an incompatible interaction between Colletotrichum fragariae and strawberry plants, the accumulation of phenolic compounds in plant leaves was observed. A particularly abundant penta-esterified ellagitannin that accumulated in response to pathogen attack was identified as 1-0-galloyl-2,3;4,6-bis-hexahydroxydiphenoyl-ß-d-glucopyranose (HeT) by mass spectroscopy and nuclear magnetic resonance. Foliar application of purified HeT prior to inoculation with a virulent pathogen was shown to increase resistance toward C. acutatum in strawberry plants and to Xanthomonas citri subsp. citri in lemon plants. The induced resistance in strawberry was associated with a rapid oxidative burst, callose deposition, a transient increase of salicylic acid in phloem, and induction of gene expression responsive to salicylic acid. Results obtained suggested that HeT could be a common plant defense response molecule capable of inducing pathogen resistance in different plant species.
Assuntos
Fragaria/metabolismo , Fragaria/microbiologia , Taninos Hidrolisáveis/metabolismo , Taninos Hidrolisáveis/farmacologia , Citrus/metabolismo , Citrus/microbiologia , Colletotrichum/patogenicidade , Fragaria/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Floema/metabolismo , Ácido Salicílico/metabolismo , Xanthomonas/patogenicidadeRESUMO
In order to describe the transformations of tannic acid during its degradation (under aerobic and anaerobic conditions) incubations were performed. To evaluate the oxygen consumption, the tannic acid was added to 1 L of water sample from Monjolinho's reservoir (22 degrees 00'S and 47 degrees 54'W); these solutions were aerated and the dissolved oxygen was monitored for 16 days, the anaerobic process was avoided. For the anaerobic and aerobic degradation, the dissolved organic carbon and the acid tannic concentrations were estimated on the samples days. The results were fitted to first-order kinetic model, being possible to verify that during the 16 days the oxygen uptake was 3.6 mg.L-1, the deoxygenation rate (kD) of this process was 0.39 day-1. The degradation coefficients were calculated through the decay of the tannic acid and organic carbon concentrations. In the aerobic process, the global decay coefficient (kG) was 0.36 day-1 and in the anaerobic 0.28 day-1. Overall, the obtained degradation coefficients suggest that the bacterioplankton of the Monjolinho's reservoir possess a high capacity of polyphenols degradation.
Assuntos
Taninos Hidrolisáveis/metabolismo , Aerobiose , Anaerobiose , Biodegradação Ambiental , Brasil , Água Doce/química , Consumo de OxigênioRESUMO
Tannase production by Aspergillus niger Aa-20 was studied in submerged (SmF) and solid-state (SSF) fermentation systems with different tannic acid and glucose concentrations. Tannase activity and productivity were at least 2.5 times higher in SSF than in SmF. Addition of high tannic acid concentrations increased total tannase activity in SSF, while in SmF it was decreased. In SmF, total tannase activity increased from 0.57 to 1.03 IU/mL, when the initial glucose concentration increased from 6.25 to 25 g/L, but a strong catabolite repression of tannase synthesis was observed in SmF when an initial glucose concentration of 50 g/L was used. In SSF, maximal values of total tannase activity decreased from 7.79 to 2.51 IU when the initial glucose concentration was increased from 6.25 to 200 g/L. Kinetic results on tannase production indicate that low tannase activity titers in SmF could be associated to an enzyme degradation process which is not present in SSF. Tannase titers produced by A. niger Aa-20 are fermentation system-dependent, favoring SSF over SmF.
Assuntos
Aspergillus niger/metabolismo , Hidrolases de Éster Carboxílico/biossíntese , Glucose/metabolismo , Taninos Hidrolisáveis/metabolismo , Aspergillus niger/efeitos dos fármacos , Aspergillus niger/enzimologia , Aspergillus niger/crescimento & desenvolvimento , Fermentação , Taninos Hidrolisáveis/farmacologia , Microbiologia Industrial/métodos , CinéticaRESUMO
The 16S rRNA sequences and selected phenotypic characteristics were determined for six recently isolated bacteria that can tolerate high levels of hydrolyzable and condensed tannins. Bacteria were isolated from the ruminal contents of animals in different geographic locations, including Sardinian sheep (Ovis aries), Honduran and Colombian goats (Capra hircus), white-tail deer (Odocoileus virginianus) from upstate New York, and Rocky Mountain elk (Cervus elaphus nelsoni) from Oregon. Nearly complete sequences of the small-subunit rRNA genes, which were obtained by PCR amplification, cloning, and sequencing, were used for phylogenetic characterization. Comparisons of the 16S rRNA of the six isolates showed that four of the isolates were members of the genus Streptococcus and were most closely related to ruminal strains of Streptococcus bovis and the recently described organism Streptococcus gallolyticus. One of the other isolates, a gram-positive rod, clustered with the clostridia in the low-G+C-content group of gram-positive bacteria. The sixth isolate, a gram-negative rod, was a member of the family Enterobacteriaceae in the gamma subdivision of the class Proteobacteria. None of the 16S rRNA sequences of the tannin-tolerant bacteria examined was identical to the sequence of any previously described microorganism or to the sequence of any of the other organisms examined in this study. Three phylogenetically distinct groups of ruminal bacteria were isolated from four species of ruminants in Europe, North America, and South America. The presence of tannin-tolerant bacteria is not restricted by climate, geography, or host animal, although attempts to isolate tannin-tolerant bacteria from cows on low-tannin diets failed.