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Changes in volatile constituents and phenolic compounds were investigated during fruit development of three pitanga biotypes. Constituents were submitted to multivariate analysis and fruit samples were differentiated by selina-1,3,7(11)-trien-8-one (38.2 ± 2.9%) and its epoxide (26.4 ± 7.2%) for the red-orange biotype; by curzerene (15.04 ± 2.1%) and atractylone (8.47 ± 2.1%) for the red biotype; and by spathulenol (3.7 ± 0.8%) and germacrone (54.7 ± 3.1%) for the purple biotype. Hydrolysable tannins such as mono-O-galloyl-d-glucose, 1,2,6-tri-O-galloyl-β-d-glucose, tellimagrandin II, and eugeniflorin D 2 were identified, as well as oenothein B as the major compound (32.43 ± 7.1 mg/g dry fruit). During pitanga's maturation, anthocyanin content increased, while flavonoid and tannin contents decreased. Higher contents of the majority of phenolic compounds occurred in the red-orange biotype. Biosynthesis of phenolic compounds was influenced by biotype and degree of maturation, whereas chemovariation in essential oil constituents was mainly due to biotypes, thus confirming essential oil chemotypes of E. uniflora., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Many studies quantify total phenolics or total tannins, but understanding the ecological role of polyphenolic secondary metabolites requires at least an understanding of the diversity of phenolic groups present. We used UPLC-MS/MS to measure concentrations of different polyphenol groups - including the four most common tannin groups, the three most common flavonoid groups, and quinic acid derivatives - in foliage from 628 eucalypts from the genera Eucalyptus, Angophora and Corymbia. We also tested for phylogenetic signal in each of the phenolic groups. Many eucalypts contained high concentrations of polyphenols, particularly ellagitannins, which have been relatively poorly studied, but may possess strong oxidative activity. Because the biosynthetic pathways of many phenolic compounds share either precursors or enzymes, we found negative correlations between the concentrations of several of the constituents that we measured, including proanthocyanidins (PAs) and hydrolysable tannins (HTs), HTs and flavonol derivatives, and HTs and quinic acid derivatives. We observed moderate phylogenetic signal in all polyphenol constituents, apart from the concentration of the prodelphinidin subunit of PAs and the mean degree of polymerisation of PAs. These two traits, which have previously been shown to be important in determining plants' protein precipitation capacity, may have evolved under selection, perhaps in response to climate or herbivore pressure. Hence, the signature of evolutionary history appears to have been erased for these traits. This study is an important step in moving away from analysing "totals" to a better understanding of how phylogenetic effects influence phenolic composition, and how this in turn influences ecological processes., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Java plum (Syzygium cumini Lam.) is a rich source of polyphenolics with many purported health benefits, but the effect of maturation on polyphenolic content is unknown. Freeze-dried samples of Java plum from seven different maturity stages were analyzed for anthocyanin, flavonol, flavanonol and hydrolysable tannin composition by HPLC. Anthocyanins were first detected at the green-pink stage of maturity and increased throughout maturation with the largest increase occurring from the dark purple to black stages of maturation. Levels of gallotannins, ellagitannins, flavonols, gallic acid and ellagic acid were highest at early stages of maturation and decreased as the fruit ripened. For production of antioxidant-rich nutraceutical ingredients, fruit should be harvested immature to obtain extracts rich in hydrolysable tannins and flavonols. The exceptional anthocyanin content of black fruit may prove useful as a source of a natural colorant., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Bergenia crassifolia L., Saxifragaceae, is an evergreen perennial plant known in traditional medicine of Russia, Mongolia and China. Polyphenols are responsible for the number of pharmacological effects of Bergenia. UPLC-DAD-QqQ-MS and LC-DAD-ESI-QTOF-MS were used for the rapid profiling of phenolic compounds, mainly hydrolysable tannins. Green leaves consisted of 55% ellagitannins, 29% gallic acid derivatives and 11% flavonoids, with the remaining gallic acid, arbutin, bergenin and caffeoyl quinic acid. In fermented leaves, 31% of gallic acid was found, followed with 28% ellagitannins, 18% gallic acid derivatives and 18% flavonoids, with the remaining caffeoyl quinic acid, bergenin and arbutin. Tellimagrandin I, pedunculagin, caffeoyl quinic acid, monogalloyl quinic acid, 1-O-galloylglucose and 1,2,6-tri-O-galloylglucose were identified for the very first time.

Hydrolysed tannins (HTs) are polyphenols, which are related to the astringency, flavour, colour, stability, medicinal value and other characteristics of many fruits and vegetables. The biosynthetic mechanism of the majority of HTs remains unknown, and many biosynthetic pathways of HTs are speculative conclusions that have not been confirmed. The fruit of Canarium album L. (Chinese olive), which is notable for its pharmacological and edible properties, is rich in HTs. The fruit has a distinctive bitter and astringent taste when initially consumed, which mellows to a sweet sensation upon chewing. HTs serve as the primary material basis for the formation of the Chinese olive fruit's astringent quality and pharmacological effects. In this study, the fruit of C. album Changying was utilised as the research material. The objective of this study was to provide a theoretical basis for the quality control of Chinese olive fruit and the application and development of its medicinal value. In addition, the study aimed to identify and screen related MYB transcription factors involved in the synthesis of HTs in the fruit and to clarify the mechanism of MYBs in the process of synthesis and regulation of HTs in Chinese olive fruit. The principal findings were as follows. A total of 83 differentially expressed Chinese olive MYB transcription factors (CaMYBs) were identified, including 54 1R-MYBs (MYB-related), 25 2R-MYBs (R2R3-MYBs), 3 3R-MYBs, and 1 4R-MYB. Through trend analysis and correlation analysis, it was found that CaMYBR04 (Isoform0032534) exhibited a significantly higher expression (FPKM) than the other CaMYBs. The full-length cDNA sequence of CaMYBR04 was cloned and transformed into strawberry. The results demonstrated that CaMYBR04 significantly enhanced the fruit's hydrolysable tannin content. Consequently, this study elucidated the function of CaMYBR04, a regulator of the Chinese olive fruit hydrolysable tannin synthesis pathway, and established a theoretical foundation for the synthesis and regulation of fruit HTs. [ABSTRACT FROM AUTHOR]

Polyphenols play a crucial role in fruit flavor. To elucidate the mechanism of fruit polyphenol metabolism, we constructed a transcriptome atlas through PacBio single-molecule real-time (SMRT) sequencing and Illumina next-generation sequencing (NGS) using Canarium album (Lour.) Raeusch., which is a fantastic fruit rich in polyphenolic compounds. In this work, PacBio full-length transcriptome assembly generated 135,439 isoforms with an average length of all isoforms of 2687.94 bp and an N50 length of 3224 bp. To gain deeper insights into the molecular mechanisms of polyphenol biosynthesis in C. album, we constructed twelve RNA-Seq libraries from four developmental stages of the fruits. We identified a total of 28,658 differentially expressed genes (DEGs). We found that many DEGs were involved in metabolic pathways, biosynthesis of secondary metabolites, biosynthesis of antibiotics, starch and sucrose metabolism, and plant hormone signal transduction. Here, we report the expression profiles of 215 DEGs encoding 27 enzymes involved in the polyphenol biosynthesis pathway in C. album. In addition, 285 differentially expressed transcription factors (TFs) continuously down-regulated in four developmental periods of C. album fruit, which may indicate their potential role in the response to polyphenol metabolism and phenylpropanoid biosynthesis pathways. This report will help us understand polyphenol biosynthesis's functions and metabolic mechanism in C. album. The transcriptome data provide a valuable resource for genetic and genomics research. They will facilitate future work exploiting C. album and other fruits used as medicine and food. [ABSTRACT FROM AUTHOR]

Hydrolysed tannins (HTs) are polyphenols, which are related to the astringency, flavour, colour, stability, medicinal value and other characteristics of many fruits and vegetables. The biosynthetic mechanism of the majority of HTs remains unknown, and many biosynthetic pathways of HTs are speculative conclusions that have not been confirmed. The fruit of Canarium album L. (Chinese olive), which is notable for its pharmacological and edible properties, is rich in HTs. The fruit has a distinctive bitter and astringent taste when initially consumed, which mellows to a sweet sensation upon chewing. HTs serve as the primary material basis for the formation of the Chinese olive fruit’s astringent quality and pharmacological effects. In this study, the fruit of C. album Changying was utilised as the research material. The objective of this study was to provide a theoretical basis for the quality control of Chinese olive fruit and the application and development of its medicinal value. In addition, the study aimed to identify and screen related MYB transcription factors involved in the synthesis of HTs in the fruit and to clarify the mechanism of MYBs in the process of synthesis and regulation of HTs in Chinese olive fruit. The principal findings were as follows. A total of 83 differentially expressed Chinese olive MYB transcription factors (CaMYBs) were identified, including 54 1R-MYBs (MYB-related), 25 2R-MYBs (R2R3-MYBs), 3 3R-MYBs, and 1 4R-MYB. Through trend analysis and correlation analysis, it was found that CaMYBR04 (Isoform0032534) exhibited a significantly higher expression (FPKM) than the other CaMYBs. The full-length cDNA sequence of CaMYBR04 was cloned and transformed into strawberry. The results demonstrated that CaMYBR04 significantly enhanced the fruit’s hydrolysable tannin content. Consequently, this study elucidated the function of CaMYBR04, a regulator of the Chinese olive fruit hydrolysable tannin synthesis pathway, and established a theoretical foundation for the synthesis and regulation of fruit HTs.

Polyphenols play a crucial role in fruit flavor. To elucidate the mechanism of fruit polyphenol metabolism, we constructed a transcriptome atlas through PacBio single-molecule real-time (SMRT) sequencing and Illumina next-generation sequencing (NGS) using Canarium album (Lour.) Raeusch., which is a fantastic fruit rich in polyphenolic compounds. In this work, PacBio full-length transcriptome assembly generated 135,439 isoforms with an average length of all isoforms of 2687.94 bp and an N50 length of 3224 bp. To gain deeper insights into the molecular mechanisms of polyphenol biosynthesis in C. album, we constructed twelve RNA-Seq libraries from four developmental stages of the fruits. We identified a total of 28,658 differentially expressed genes (DEGs). We found that many DEGs were involved in metabolic pathways, biosynthesis of secondary metabolites, biosynthesis of antibiotics, starch and sucrose metabolism, and plant hormone signal transduction. Here, we report the expression profiles of 215 DEGs encoding 27 enzymes involved in the polyphenol biosynthesis pathway in C. album. In addition, 285 differentially expressed transcription factors (TFs) continuously down-regulated in four developmental periods of C. album fruit, which may indicate their potential role in the response to polyphenol metabolism and phenylpropanoid biosynthesis pathways. This report will help us understand polyphenol biosynthesis’s functions and metabolic mechanism in C. album. The transcriptome data provide a valuable resource for genetic and genomics research. They will facilitate future work exploiting C. album and other fruits used as medicine and food.

Terminalia hadleyana (subsp. carpentariae C. T. White) is native to Northern Australia where fruits of this plant have been used as a traditional food by the Australian Indigenous people. The aim of this study was to evaluate the morphology, chemical composition, functional (e.g. vitamin C, phenolic content) and antimicrobial properties of T. carpentariae fruits, harvested from the wild at full maturity. Variability has been observed in both fruit morphology (size and weight) and chemical composition. Proximate analysis showed that these fruits have high concentration of dietary fibre (DF) (51.2 g/100 gDW), and minerals such as K (1780 mg/100 g DW), Ca (373 mg/100 g DW) and Mg (150 mg/100 g DW). High levels of total phenolic content (TPC) (11,392 mg GAE/100 g DW) and vitamin C (11,046 mg/100 g DW) were also observed. Fruit extracts also showed inhibitory effects against the growth of foodborne microorganisms such as Staphylococcus aureus, methicillin resistant Staphylococcus aureus, Pseudomonas aeruginosa and Shewanella putrefaciens. Overall, these results contribute to provide with relevant information of the potential of T. carpentariae fruit as a functional ingredient to the Australian Indigenous communities and the emerging Australian native food industry. [ABSTRACT FROM AUTHOR]

Summary: Although tannins have been an important focus of studies of plant–animal interactions, traditional tannin analyses cannot differentiate between the diversity of structures present in plants. This has limited our understanding of how different mixtures of these widespread secondary metabolites contribute to variation in biological activity.We used UPLC‐MS/MS to determine the concentration and broad composition of tannins and polyphenols in 628 eucalypt (Eucalyptus, Corymbia and Angophora) samples, and related these to three in vitro functional measures believed to influence herbivore defence: protein precipitation capacity, oxidative activity at high pH and capacity to reduce in vitro nitrogen (N) digestibility.Protein precipitation capacity was most strongly correlated with concentrations of procyanidin subunits in proanthocyanidins (PAs), and late‐eluting ellagitannins. Capacity to reduce in vitro N digestibility was affected most by the subunit composition and mean degree of polymerisation (mDP) of PAs. Finally, concentrations of ellagitannins and prodelphinidin subunits of PAs were the strongest determinants of oxidative activity.The results illustrate why measures of total tannins rarely correlate with animal feeding responses. However, they also confirm that the analytical techniques utilised here could allow researchers to understand how variation in tannins influence the ecology of individuals and populations of herbivores, and, ultimately, other ecosystem processes. [ABSTRACT FROM AUTHOR]

Hydrolysable tannins (HTs) are useful secondary metabolites that are responsible for pharmacological activities and astringent taste, flavor, and quality in fruits. They are also the main polyphenols in Canarium album L. (Chinese olive) fruit, an interesting and functional fruit that has been cultivated for over 2000 years. The HT content of C. album fruit was 2.3–13 times higher than that of berries with a higher content of HT. 1-galloyl-β-d-glucose (βG) is the first intermediate and the key metabolite in the HT biosynthesis pathway. It is catalyzed by UDP-glucosyltransferases (UGTs), which are responsible for the glycosylation of gallic acid (GA) to form βG. Here, we first reported 140 UGTs in C. album. Phylogenetic analysis clustered them into 14 phylogenetic groups (A, B, D–M, P, and Q), which are different from the 14 typical major groups (A~N) of Arabidopsis thaliana. Expression pattern and correlation analysis showed that UGT84A77 (Isoform0117852) was highly expressed and had a positive correlation with GA and βG content. Prokaryotic expression showed that UGT84A77 could catalyze GA to form βG. These results provide a theoretical basis on UGTs in C. album, which will be helpful for further functional research and availability on HTs and polyphenols.

Quali-quantitative analyses of anthocyanins and non-anthocyanin phenolic compounds performed with the use of liquid chromatography coupled with high resolution mass spectrometry, were evaluated in juice of pomegranate fruits (‘Dente di Cavallo’), in relation to different light exposures (North, South, West and East). A total of 16 compounds were identified, including phenolic acids, flavonoids, hydrolysable tannins, and anthocyanins, known for their health-promoting effects. Striking differences were observed about the total phenolic content, which was high in juices from fruits with east- and north-facing position, while it was lower in juices facing south. The greatest contents of total flavonoids and anthocyanins were recorded in fruit juices with southern exposure; however, there are no great differences in the content in phenolic acids. Tannins were mainly synthesized in fruit juices with West exposure. The results showed that the position within the tree had no significant effects on color juice, however, it significantly (p < 0.05) affected data on fruit weight, soluble sugars and juice yield. Remarkable synergies existed among polyphenols and phytochemicals in pomegranate juice, but collecting fruits with different solar exposure could enhance different health benefits, i.e., the juices with higher polyphenols content could have more anticancer effect or those with higher tannins content could have more antimicrobial effect.

In this study, we tested the growth inhibition effect of 22 individual ellagitannins and of pentagalloylglucose on four bacterial species, i.e., Clostridiales perfringens, Escherichia coli, Lactobacillus plantarum and Staphylococcus aureus. All tested compounds showed antimicrobial effects against S. aureus, and almost all against E. coli and C. perfringens. For L. plantarum, no or very weak growth inhibition was detected. The level of inhibition was the greatest for S. aureus and the weakest for C. perfringens. For S. aureus, the molecular size or flexibility of ellagitannins did not show a clear relationship with their antimicrobial activity, even though rugosins E and D and pentagalloylglucose with four or five free galloyl groups had a stronger growth inhibition effect than the other ellagitannins with glucopyranose cores but with less free galloyl groups. Additionally, our results with S. aureus showed that the oligomeric linkage of ellagitannin might have an effect on its antimicrobial activity. For E. coli, the molecular size, but not the molecular flexibility, of ellagitannins seemed to be an important factor. For C. perfringens, both the molecular size and the flexibility of ellagitannin were important factors. In previous studies, corilagin was used as a model for ellagitannins, but our results showed that other ellagitannins are much more efficacious; therefore, the antimicrobial effects of ellagitannins could be more significant than previously thought.

The work aimed at optimizing the extraction protocol of ʽGabsi’ pomegranate peel (PP) and evaluating the total phenol content and profile, antioxidant activity and antimicrobial effect of the extracts obtained. Water and methanol as solvents were compared at different peel/solvent ratios; three different temperatures were also compared for the water extraction. Methanol pomegranate peel extract (MPPE) and water extracts (WPPE) were analysed for their DPPH antioxidant activity and polyphenol profile and content by HPLC/DAD and HPLC/MS. Different concentrations of MPPE and WPPE (ranging from 0.061 to 0.304 and from 0.072 to 0.361 g dry extract/mL, respectively) were also tested in vitro against Penicillium digitatum , Pseudomonas putida and Saccharomyces cerevisiae to determine the minimum inhibitory concentration (MIC). The MPPE and WPPE had comparable antioxidant activity (4081.43 and 3497.02 mmol Trolox/g, respectively). Hydrolysable tannins represented the main polyphenols in pomegranate peel, with punicalagin as the major compound. In general, MPPE dilutions tested in well-diffusion assays were more effective against targeted microorganisms compared with WPPE; indeed, only the highest WPPE concentration, was able to inhibit the growth of targeted microrganisms. Viability tests in liquid medium confirmed the highest antimicrobial capacity of MPPE, although even the WPPE was able to reduce P. putida and S. cerevisiae populations by up to 3.15 and 2.52 log CFU/mL, respectively. [ABSTRACT FROM AUTHOR]

A bio-guided study of leaf extracts allowed the isolation of two new macrobicyclic hydrolysable tannins, namely merianin A (1) and merianin B (2), and oct-1-en-3-yl β-xylopyranosyl-(1„-6’)-β-glucopyranoside (3) from Meriania hernandoi, in addition to 11 known compounds reported for the first time in the Meriania genus. The structures were elucidated by spectroscopic analyses including one- and two-dimensional NMR techniques and mass spectrometry. The bioactivities of the compounds were determined by measuring the DPPH radical scavenging activity and by carrying out antioxidant power assays (FRAP), etiolated wheat coleoptile assays and phytotoxicity assays on the standard target species Lycopersicum esculentum W. (tomato). Compounds 1 and 2 exhibited the best free radical scavenging activities, with FRS50 values of 2.0 and 1.9 µM, respectively.

Main conclusion : The polyphenol profiles of 18 cell cultures from 12 plant species were screened. The detected polyphenol fingerprints were diverse and differed from polyphenol profiles typically found in corresponding plant species. Cell cultures originating from 12 different plant species growing or grown in the Nordic countries were screened for their ability to synthesize polyphenols to assess their suitability for future studies and applications. The focus was on plant families Rosaceae and Ericaceae. On average, the Rosaceae cultures were the most efficient to produce hydrolysable tannins and the Ericaceae cultures were the most efficient to produce proanthocyanidins. This is in line with the general trend of polyphenols found in Rosaceae and Ericaceae leaves and fruits, even though several individual cell cultures differed from natural plants in their polyphenolic composition. Overall, several of the studied cell cultures exhibited capability in producing a large variety of polyphenols, including tannins with a high molecular weight, thus also showing promise for further studies concerning, for example, the accumulation of specific polyphenols or biosynthesis of polyphenols in the cell cultures. [ABSTRACT FROM AUTHOR]

The discovery of the ellagitannin geraniin was made exactly 40 years ago. It is a secondary metabolite found in plants and is categorised as a hydrolysable tannin under the huge family of polyphenolic compounds. At present, the occurrence of geraniin has been verified in at least 71 plant species, many of which are used in traditional medicine. Hence, like other polyphenols, geraniin has also received widespread interest as a research focus to unearth its beneficial biological effects and therapeutic values apart from understanding its chemical properties, biosynthesis and interaction with the body system. Indeed, it has been demonstrated that geraniin possesses antioxidant, antimicrobial, anticancer, cytoprotective, immune-modulatory, analgesic properties besides exerting promising therapeutic effects on hypertension, cardiovascular disease and metabolic dysregulation. The objective of this review is to summarise the current knowledge about the basic chemistry, natural sources, isolation techniques, biosynthesis, pharmacokinetics and pharmacodynamics of geraniin. With reference to this information, the clinical significance, obstacles and future perspectives in geraniin research will also be scrutinised. [ABSTRACT FROM AUTHOR]

Polyphenols are known to interact with protein fractions of feed ingredients in the digestive tract thereby affecting the digestibility. These effects may differ depending on the chemical composition of the protein fractions. Thus, the objective of the study was to study the impact of a tannin-rich chestnut extract (CHE) on the in-vitro digestibility (IVD) of soy protein isolate (SPI), screw-pressed soybean (SPS) and solvent-extracted soybean (SES). In addition, CHE-derived metabolites were tested for their effects on intestinal epithelial integrity. The SPI, SPS, and SES were digested in vitro without (SPI-, SPS-, SES-) or with CHE (SPI+, SPS+, SES+) or as a control (C) solely CHE. The metabolites and the polyphenols content after digestion of the soy-based products with or without CHE were quantified. The trans-epithelial resistance (TEER) was monitored in porcine jejuna in the presence of CHE-derived metabolites at three dilutions (1:4, 1:8, and 1:16 v/v) or in their absence. The claudin-1 (CLDN1), occludin (OCLN) and zonula occludens-1 (ZO1) tight junctions-protein expressions were determined. Finally, the effects of CHE-metabolites against indomethacin (INDO)-induced decrease of TEER were tested ex vivo. The CHE decreased the IVD (P < 0.05) and decreased the detectable polyphenol content (P < 0.05) after digestion of CHE with SPI, SPS, or SES. The SPI and SPI+CHE were the samples with the highest content of metabolites generated after the digestion, while CHE presented the lowest content of metabolites. No detrimental effects on TEER were observed. The 1:8 dilution increased (P < 0.05) both ZO1 and OCLN protein expression by up to + 60% compared to the control, while the dilution 1:16 increased ZO1 expression by + 100% without affecting OCLN expression. The 1:16 dilution also protected the jejunum from the effects induced by INDO. These results suggest that the anti-nutritional effects exerted by CHE on soy-based meals IVD may depend on the meal's chemical composition. Moreover, we showed that CHE polyphenols exert protective effects on the intestinal epithelium integrity ex vivo at low concentrations. • Chestnut extracts inhibit in vitro digestibility and the total polyphenol content in soy-based products depends on their chemical composition. • Chestnut extracts are an important source of polyphenols and digestive processes affect their bioavailability. • Low concentrations of metabolites obtained by the chestnut extracts' digestion exert protective effects at intestinal level. [ABSTRACT FROM AUTHOR]

Microscopic studies on isolated ozone (O 3 ) effects or on those in synergy with light stress commonly report the induction of polyphenols that exhibit different aspects within the vacuole of photosynthesizing cells. It has been assumed that these different aspects are randomly spread in the symptomatic (injured) regions of the leaf blade. Interestingly, secretory ducts that constitutively produce polyphenols also exhibit these same variations in their vacuolar aspect, in a spatial sequence related to the destiny of these cells (e.g., programmed cell death (PCD) in lytic secretion processes). Here, we demonstrate that the deposition pattern of polyphenols prior to the establishment of the hypersensitive-like response, a type of PCD caused by O 3 , follows the same one observed in the epithelial cells of the constitutive lysigenous secretory ducts. Astronium graveolens , an early secondary Brazilian woody species, was selected based on its susceptibility to high light and presence of secretory ducts. The synergism effects were assessed by exposing plants to the high O 3 concentrations at an urban site in São Paulo City. Confocal, widefield and light microscopies were used to examine polyphenols' occurrence and aspects. The spatial pattern of polyphenols distribution along the leaflets of plants submitted to the synergism condition, in which a dense vacuolar aspect is the target of a cell destined to death, was also observed in the constitutive secretory cells prior to lysis. This similar structural pattern may be a case of homology of process involving both the constitutive (secretory ducts) and the induced (photosynthesizing cells) defenses. [ABSTRACT FROM AUTHOR]

Pomegranate (Punica granatum (Linn.)) husk is an agri-food residual material, particularly rich in polyphenolic phytochemicals. An experimental setup based on a 2³-full factorial central composite design was implemented with the aim to optimising recovery of polyphenol extraction from pomegranate husks, using ethanol/water/citric acid as the extracting medium. The factors considered were (i) the pH of the medium, (ii) the ethanol concentration and (iii) the extraction time. Optimal extraction afforded extracts exceptionally enriched in total polyphenols, with the yield being 324.9mg gallic acid equivalents per g of dry weight. Liquid chromatography-electrospray ionisation mass spectrometry of the optimally obtained extract revealed that the principal phytochemicals recovered were punicalins A and B and ellagic acid. [ABSTRACT FROM AUTHOR]

Five mung bean cultivars varying in seed coat color were analyzed for polyphenol content. The effect of soaking and germination on the polyphenol content and polyphenol oxidase activity was investigated. The level of total polyphenols was found to be in the range of 310–340 mg/100 g in whole seeds. Soaking reduced the total polyphenols, whereas germination for 48 h increased total polyphenol content by 41–76%. The hydrolysable tannins, condensed tannins, and hydrolysable tannins/condensed tannins index increased with an increase in period of germination. The total and percent condensed tannins content slightly decreased while hydrolysable tannins increased during germination. Maximum polyphenol oxidase activity of 102–108 units was observed in 24 h germinated seeds. There was no significant correlation found between the polyphenolic content and polyphenol oxidase activity in germinating mung bean seeds. These findings demonstrated that the mung beans are fair sources of polyphenols, thus having great potential as a source of natural antioxidants. [ABSTRACT FROM PUBLISHER]

Abstract: The effects of interferon (IFN-γ), lipopolysaccharide (LPS), and some polyphenols as individual stimuli, as well as in various combinations on NO production in non-infected and infected macrophage-like RAW 264.7 cells were investigated, with emphasis on the NO/parasite kill relationship. In non-infected and in Leishmania parasitized cells, gallic acid significantly inhibited the IFN-γ and LPS-induced NO detected in the supernatant. This effect was less prominent in IFN-γ- than in LPS-stimulated cells. Interestingly, and in contrast to non-infected cells, gallic acid inhibited NO production only when added within 3h after IFN-γ+LPS. Addition of gallic acid following prolonged incubation with IFN-γ+LPS periods (24h) no longer inhibited, sometimes even enhanced NO release. Notably, an excellent NO/parasite kill relationship was evident from all the experiments. This study was extended to a series of polyphenols (3-O-shikimic acid, its 3,5-digalloylated analogue, catechin, EGCG, and a procyanidin hexamer) with proven immunostimulatory activities. Although these compounds themselves were found to be weak NO-inducers, the viability of intracellular Leishmania parasites was considerably reduced. Furthermore, their dose-dependent effects on macrophage NO release was determined in the presence of IFN-γ and/or LPS. Again, non-infected and infected cells differed significantly in the NO response, while inhibition of IFN-γ and/or LPS-induced NO production by the tested polyphenols strongly depended on the given time of exposure and the sequence of immunological stimuli. A strong inverse correlation between NO levels and intracellular survival rates of Leishmania parasites supported the assumption that the observed inhibition of NO was not simply due to interference with the Griess assay used for detection. [Copyright &y& Elsevier]

Abstract: Four different liquid model matrices were utilised to study the leaching of polyphenols from oak chips. The matrices included distilled water, 12% (v/v) ethanol, 12% (v/v) ethanol adjusted to pH 3.4, and 55% (v/v) ethanol. Extraction of phenolics into the liquid systems was monitored by the estimation of the total polyphenol concentration, using the Folin–Ciocalteu method. The in vitro antiradical activity was also recorded using the stable DPPH radical, to ascertain enrichment of the solutions with potentially antioxidant compounds. As a final step, the polyphenolic composition of each matrix was characterised by means of liquid chromatography–electrospray ionisation mass spectrometry. The kinetics of polyphenol leaching into the liquid phase was found to obey a 2nd parameter power equation of the type y = axb , which produced a good fit of the data (p <0.0001). Kinetics was faster in distilled water up to a point, where after polyphenol extraction occurred at higher rate in the 55% ethanolic solution. The antiradical activity in all cases was highly correlated with total polyphenol concentration (p <0.001), providing that the amount of polyphenols extracted into the liquid media exerted a proportional antioxidant effect. The analytical examination by liquid chromatography–mass spectrometry revealed that the compounds implicated are hydrolysable tannins and hydrolysis products thereof. [Copyright &y& Elsevier]

Abstract: In the field of plant–herbivore interactions, research methods where plant secondary metabolites are manipulated are becoming more and more popular. Among the most commonly used is tannic acid. However, recent studies have shown that different tannic acid preparations are not comparable in their tannin structures. While tannic acids are meant to contain only gallotannins (GTs), some commercial preparations compose mainly of more simple galloylglucoses (that have, e.g. much lower protein precipitation capacity than GTs) or even of gallic acid (the hydrolysis product of GTs). Another group of tannins used in feeding trials is condensed tannins (CTs), usually in the form of quebracho tannin. Quebracho, however, contains different CT structures than, e.g. leaves of many deciduous trees. Additionally, when analysed with the common acid-butanol assay for total CTs, quebracho tannins give even 30-fold lower absorbance than the CTs of those deciduous trees. In addition to above problems it has been shown that different tannins can give different response even within the same herbivore species, and that the same tannin structure can cause different response in different herbivores. Below we review these problems, as well as some means to deal with them. [Copyright &y& Elsevier]

Abstract: Some polyphenol-containing extracts (Pelargonium sidoides, Phyllanthus amarus) and representatives of simple phenols (shikimic acid 3- and 5-O-gallate), flavan-3-ols (epigallocatechin 3-gallate), proanthocyanidins (a hexamer) and hydrolysable tannins (corilagin, casuariin, geraniin) were studied for gene expressions (iNOS, IL-1, IL-10, IL-12, IL-18, TNF-α, IFN-α/γ) by RT-PCR. All extracts and compounds were capable of enhancing the iNOS and cytokine mRNA levels in parasitised cells when compared with those in non-infected conditions. [Copyright &y& Elsevier]

Abstract: The antileishmanial and immunomodulatory potencies of a total of 67 tannins and structurally related compounds were evaluated in terms of extra- and intra-cellular leishmanicidal effects and macrophage activation for release of nitric oxide (NO), tumour necrosis factor (TNF) and interferon (IFN)-like activities. Their effects on macrophage functions were further assessed by expression analysis (iNOS, IFN-α, IFN-γ, TNF-α, IL-1, IL-10, IL-12, IL-18). With few exceptions, e.g., caffeic acid derivatives, these polyphenols revealed little direct toxicity for extracellular promastigote Leishmania donovani or L. major strains. In contrast, many polyphenols appreciably reduced the survival of the intracellular, amastigote parasite form in vitro. Upon activation, e.g., by immune response mediators such as IFN-γ, macrophages may transform from permissive host to leishmanicidal effector cells. Our data from functional bioassays suggested that the effects of polyphenols on intracellular Leishmania parasites were due to macrophage activation rather than direct antiparasitic activity. Gene expression analyses not only confirmed functional data, they also clearly showed differences in the response of infected macrophages when compared to that of noninfected cells. Conspicuously, infected macrophages showed augmented and prolonged activation of host defense mechanisms, indicating that parasitised macrophages were exquisitely predisposed or “primed” to react to activating molecules such as polyphenols. This promotive effect may be of special benefit, e.g., stimulation of the non-specific immune system selectively at the site of infection and when needed. Although these data provide the basis for an immunological concept of plant polyphenols for their beneficial effects in various infectious conditions, in vivo experiments are essential to prove the therapeutic benefits of polyphenolic immunomodulators. [Copyright &y& Elsevier]

Oxidative stress is involved in the pathogenesis of numerous diseases. Nevertheless, no optimal natural antioxidant has been found for therapeutics, therefore polyphenol antioxidants have been looked for in myrtle leaves, a plant that in folk medicine has been used as anti-inflammatory drug. Antioxidant-rich fractions were prepared from myrtle ( Myrtus communis L.) leaves liquid-liquid extraction (LLE) with different solvents. All myrtle extracts were very rich in polyphenols. In particular, hydroalcoholic extracts contain galloyl-glucosides, ellagitannins, galloyl-quinic acids and flavonol glycosides; ethylacetate extract and aqueous residues after LLE are enriched in flavonol glycosides and hydrolysable tannins (galloyl-glucosides, ellagitannins, galloyl-quinic acids), respectively. Qualitative and quantitative analysis for the single unidentified compound was also performed. Human LDL exposed to copper ions was used to evaluate the antioxidant activity of the myrtle extracts. Addition of these extracts did not affect the basal oxidation of LDL but dose-dependently decreased the oxidation induced by copper ions. Moreover, the myrtle extracts reduce the formation of conjugated dienes. The antioxidant effect of three myrtle extracts decreased in the following order: hydroalcoholic extracts, ethylacetate and aqueous residues after LLE. The extracts had the following IC 50 : 0.36, 2.27 and 2.88 μM, when the sum of total phenolic compounds was considered after the correction of molecular weight based on pure compounds. Statistical analysis showed a significant difference among hydroalcoholic extracts vs. the ethylacetate and aqueous residues after LLE. These results suggest that the myrtle extracts have a potent antioxidant activity mainly due to the presence of galloyl derivatives. [ABSTRACT FROM AUTHOR]

Hydrolysable tannins (HTs) are useful secondary metabolites that are responsible for pharmacological activities and astringent taste, flavor, and quality in fruits. They are also the main polyphenols in Canarium album L. (Chinese olive) fruit, an interesting and functional fruit that has been cultivated for over 2000 years. The HT content of C. album fruit was 2.3–13 times higher than that of berries with a higher content of HT. 1-galloyl-β-d-glucose (βG) is the first intermediate and the key metabolite in the HT biosynthesis pathway. It is catalyzed by UDP-glucosyltransferases (UGTs), which are responsible for the glycosylation of gallic acid (GA) to form βG. Here, we first reported 140 UGTs in C. album. Phylogenetic analysis clustered them into 14 phylogenetic groups (A, B, D–M, P, and Q), which are different from the 14 typical major groups (A~N) of Arabidopsis thaliana. Expression pattern and correlation analysis showed that UGT84A77 (Isoform0117852) was highly expressed and had a positive correlation with GA and βG content. Prokaryotic expression showed that UGT84A77 could catalyze GA to form βG. These results provide a theoretical basis on UGTs in C. album, which will be helpful for further functional research and availability on HTs and polyphenols. [ABSTRACT FROM AUTHOR]

In this study, we screened 287 plant tissue samples from 175 plant species for their phenolic profiles. The samples were oxidized enzymatically in planta or at high pH in vitro to determine how these two oxidative conditions would alter the initial polyphenol profiles of the plant. Compounds that contained a pyrogallol or dihydroxyphenethyl group were highly active at pH 10. Enzymatic oxidation favored compounds that contained a catechol group, whereas compounds containing a pyrogallol group or monohydroxysubstituted phenolic moieties at most were oxidized less frequently. This study gives a broad overview of the distribution and alkaline oxidative activities of water-soluble phenolic compounds in plants as well as the enzymatic oxidative activities of various plant tissues. Image 1 • Phenolics were screened from a wide variety of plants across the plant phylogeny. • At pH 10, the most active compounds contained pyrogallol or dihydroxyphenethyl units. • Alkaline oxidative activity of moderately active compounds varied between samples. • Enzymatic activity varied between the plants samples. • In enzymatic oxidation, the compounds containing a catechol group were favored. [ABSTRACT FROM AUTHOR]

Quali-quantitative analyses of anthocyanins and non-anthocyanin phenolic compounds performed with the use of liquid chromatography coupled with high resolution mass spectrometry, were evaluated in juice of pomegranate fruits ('Dente di Cavallo'), in relation to different light exposures (North, South, West and East). A total of 16 compounds were identified, including phenolic acids, flavonoids, hydrolysable tannins, and anthocyanins, known for their health-promoting effects. Striking differences were observed about the total phenolic content, which was high in juices from fruits with east- and north-facing position, while it was lower in juices facing south. The greatest contents of total flavonoids and anthocyanins were recorded in fruit juices with southern exposure; however, there are no great differences in the content in phenolic acids. Tannins were mainly synthesized in fruit juices with West exposure. The results showed that the position within the tree had no significant effects on color juice, however, it significantly (p < 0.05) affected data on fruit weight, soluble sugars and juice yield. Remarkable synergies existed among polyphenols and phytochemicals in pomegranate juice, but collecting fruits with different solar exposure could enhance different health benefits, i.e., the juices with higher polyphenols content could have more anticancer effect or those with higher tannins content could have more antimicrobial effect. [ABSTRACT FROM AUTHOR]

Combretum padoides Engl. & Diels, C. psidioides Welv. and C. zeyheri Sond. are used for the treatment of infections and tuberculosis related symptoms in African traditional medicine. In order to verify these uses, extracts were screened for their growth inhibitory effects against M. smegmatis ATCC 14468. Ultra-high pressure liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC/QTOF-MS) and GC-MS were used to investigate the polyphenolic composition in the active extracts. The lowest minimum inhibitory concentration (MIC), 625 µg/mL, was shown by a methanol extract of the stem bark of C. psidioides. A butanol extract of C. psidioides gave large inhibition zone diameters (IZD 21 mm) and inhibited 84% of the mycobacterial growth at 312 µg/mL. Combretastatin B-2 and dihydrostilbene derivatives were present in the methanol extract of C. psidioides, whereas the butanol extract of this species contained punicalagin, corilagin, and sanguiin H-4. Methanol and butanol extracts of the stem bark of C. padoides gave large inhibition zone diameters (IZD 26.5 mm) and MIC values of 1250 and 2500 µg/mL, respectively. C. padoides contained an ellagitannin with a mass identical to punicalagin ([M-H]− 1083.0587) and a corilagin like derivative ([M-H]− 633.0750) as well as ellagic acid arabinoside and methyl ellagic acid xyloside. A butanol extract of the roots of C. zeyheri showed mild antimycobacterial activity and contained a gallotannin at m/z [M-H]− 647.0894 as the main compound along with punicalagin and three unknown ellagitannins at m/z [M-H]− 763.0788, 765.0566, and 817.4212. Our results indicate that the studied species of Combretum contain phenolic and polyphenolic compounds with possible potential as leads for antimycobacterial drugs or as adjuvants for conventional anti-TB drugs. [ABSTRACT FROM AUTHOR]

A bio-guided study of leaf extracts allowed the isolation of two new macrobicyclic hydrolysable tannins, namely merianin A (1) and merianin B (2), and oct-1-en-3-yl β-xylopyranosyl-(1"-6')-β-glucopyranoside (3) from Meriania hernandoi, in addition to 11 known compounds reported for the first time in the Meriania genus. The structures were elucidated by spectroscopic analyses including one- and two-dimensional NMR techniques and mass spectrometry. The bioactivities of the compounds were determined by measuring the DPPH radical scavenging activity and by carrying out antioxidant power assays (FRAP), etiolated wheat coleoptile assays and phytotoxicity assays on the standard target species Lycopersicum esculentum W. (tomato). Compounds 1 and 2 exhibited the best free radical scavenging activities, with FRS50 values of 2.0 and 1.9 µM, respectively. [ABSTRACT FROM AUTHOR]