Condensed Tannins Research Articles

Modulatory role of terminal monomeric flavan-3-ol units in the viscoelasticity of dentin.

Flavan-3-ol monomers are the building blocks of proanthocyanidins (PACs), natural compounds from plants shown to mediate specific biologic activities on dentin. While the stereochemistry of the terminal flavan-3-ols, catechin (C) versus epicatechin (EC), impacts the biomechanical properties of the dentin matrix treated with oligomeric PACs, structure-activity relationships driving this bioactivity remain elusive. To gain insights into the modulatory role of the terminal monomers, two highly congruent trimeric PACs from Pinus massoniana only differing in the stereochemistry of the terminal unit (Trimer-C vs. Trimer-EC) were prepared to evaluate their chemical characteristics as well as their effects on the viscoelasticity and biostability of biomodified dentin matrices via infrared spectroscopy and multi-scale dynamic mechanical analyses. The subtle alteration of C versus EC as terminal monomers lead to distinct immediate PAC-trimer biomodulation of the dentin matrix. Nano- and micro-dynamic mechanical analyses revealed that Trimer-EC increased the complex moduli (0.51 GPa) of dentin matrix more strongly than Trimer-C (0.26 GPa) at the nanoscale length (p < 0.001), whereas the reverse was found at the microscale length (p < .001). The damping capacity (tan δ) of dentin matrix decreased by 70% after PAC treatment at the nano-length scale, while increased values were found at the micro-length scale (~0.24) compared to the control (0.18 ; p < .001). An increase in amide band intensities and a decrease of complex moduli was observed after storage in simulated body fluid for both Trimer-C and Trimer-EC modified dentin. The stereochemical configuration of the terminal monomeric units, C and EC, did not impact the chemo-mechanical stability of dentin matrix.

Targeted metabolomics reveals key phenolic changes in pecan nut quality deterioration under different storage conditions.

Pecan nuts are highly enriched in phenolic compounds, which contribute to the health benefits of pecans. Phenolic compounds represent the main oxidation reaction substrates, thus leading to quality deterioration, namely pellicle browning or a decrease in beneficial effects during pecan storage. Hence, four different storage conditions were performed for 180 d to simulate real production situations. Targeted metabolomics was chosen to identify the specific phenolic compounds involved in quality deterioration under different storage conditions in 0, 90, and 180 d samples. A total of 118 phenolic compounds were detected, nine of which were identified for the first time in pecan. The total phenolic content (TPC) and antioxidant capacities initially demonstrated high scores, after which they tended to decrease during the storage process. The significantly modified phenolic compounds during storage were selected as the metabolite markers of pecan quality deterioration, including catechin, procyanidin (PA) trimer, PA tetramer, trigalloyl hexahydroxydiphenoyl (HHDP) glucose, and tetragalloyl hexoside. Fresh pecan kernels resulted in more pronounced changes in hydrolysable tannins (HTs), whereas dry kernels resulted in the most accentuated changes in condensed tannins (CTs). To the best of our knowledge, this is the first attempt to study individual phenolic changes during storage of pecan in such massive amounts. The results can offer a valuable theoretical basis for future control of pecan quality deterioration through phenolics during storage.

Lotus Seedpod Oligomeric Procyanidin Nanoliposomes Targeting TLR4/NF-κB Reduce Inflammation and Oxidative Stress in Patients with Traumatic Brain Injury

The inflammatory-immune response secondary to nerve injury is an important mechanism for craniocerebral injury. Procyanidins from lotus seedpods (LSPCs) are one of the main active ingredients isolated from the mature receptacles of the Nymphaeaceae family lotus plant. LSPCs exhibit strong free radical scavenging and antioxidant activities. The objective of this study was to determine the effects of LSPC nanoliposomes on traumatic brain injury (TBI). In a TBI rat model, LSPC nanoliposomes were injected intraperitoneally. Inflammatory factors and oxidative stress molecules were detected with ELISAs and RT-PCR. The TLR4/NF-κB signaling pathway was explored using Western blotting. The modified neurological severity scores (mNSS) increased in the TBI group compared with the scores in the Sham group. The water maze test indicated latency in finding the platform was prolonged and staying time in the platform quadrant and the number of times crossing the platform were reduced in the TBI group. Treatment with LSPCs significantly reduced the mNSS scores in rats with TBI and significantly reduced the time to find the platform, increased the residence time in the platform quadrant, and increased the frequency of crossing the platform during the water maze test. In addition, brain edema was reduced in rats with TBI after intraperitoneal injection of LSPCs. Iba-1, IL-1β, IL-6, and TNF-α levels were reduced after intraperitoneal injection of LSPCs. MDA levels were also reduced, while GSH-Px and SOD levels increased. After intraperitoneal injection of LSPCs, TLR4, MyD88, and pNF-κB p65 were significantly attenuated. Activation of TLR4 prevented the protective effects of LCPCs in rats with TBI. The results of this study demonstrate that LSPCs attenuate activation of the TLR4/NF-κB pathway in rats with TBI, thereby reducing microglia activation, inflammation, and oxidative stress.

Sulla (Hedysarum coronarium L.) Response to Drought Stress during Early Vegetative Stage.

Sulla (Hedysarum coronarium L.) is a Mediterranean biannual anthelmintic forage. Due to its high productivity, nutraceutical value, and suitability for harsh environments, interest in this crop is growing. Under the current scenario of climate change and water scarcity, it is important to evaluate crop drought tolerance, especially for newly bred materials. Drought stress and well-watered conditions (50 vs. 80% of the field capacity) were applied in a pot experiment to compare responses of the widespread commercial variety Bellante with those of a recently released variety named 'Centauro', currently registered in the Italian national register of plant varieties but not yet available on the market. Compared to the well-watered treatment, drought-stressed plants showed lower values of fresh biomass (-69%), number of leaves (-68%), and root length (-49%). The Centauro cv. showed a different architecture to Bellante with more shoots (+43% P < 0.05) and a trend for more leaves (+25% P = 0.08). These traits are possibly related to its superior palatability. Centauro also developed a higher root length (+70%, P < 0.05) across irrigation levels. Drought stress affected condensed tannin (CT) content. A significant genotype × environment interaction was found with Centauro displaying more (+50%) and less (-35%) CT than Bellante under drought stress and well-watered conditions, respectively. The higher constitutive root length density of Centauro may be exploited in breeding programs aimed at improving the root sink, given the role of this trait in resource acquisition capacity and root-derived ecosystem services.

Insecticidal Activity of Tannins from Selected Brown Macroalgae against the Cotton Leafhopper Amrasca devastans.

Seaweeds, also known as marine macroalgae, are renewable biological resources that are found worldwide and possess a wide variety of secondary metabolites, including tannins. Drifted brown seaweed (DBSW) is particularly rich in tannins and is regarded as biological trash. The cotton leaf hopper Amrasca devastans (Distant) has caused both quantitative and qualitative losses in cotton production. Drifted brown seaweeds (DBSWs) were used in this study to extract, qualitatively profile, and quantify the levels of total tannins, condensed tannins, hydrolyzable tannins, and phlorotannins in the seaweeds; test their insecticidal activity; and determine the mechanism of action. The largest amount of tannin extract was found in Sargassum wightii Greville (20.62%) using the Soxhlet method (SM). Significantly higher amounts of hydrolyzable tannins (p = 0.005), soluble phlorotannins (p = 0.005), total tannins in the SM (p = 0.003), and total tannins in the cold percolation method (p = 0.005) were recorded in S. wightii. However, high levels of condensed tannins (CTAs) were observed in Turbinaria ornata (Turner) J. Agardh (p = 0.004). A. devastans nymphs and adults were examined for oral toxicity (OT) and contact toxicity (CT) against DBSW tannin crude extract and column chromatographic fractions 1 (Rf = 0.86) and 2 (Rf = 0.88). Stoechospermum polypodioides (J.V. Lamouroux) J. Agardh crude tannin was highly effective against A. devastans using the OT method (LC50, 0.044%) when compared with the standard gallic acid (LC50, 0.044%) and tannic acid (LC50, 0.122%). Similarly, S. wightii fraction 2 (LC50, 0.007%) showed a greater insecticidal effect against A. devastans adults in OT than gallic acid (LC50, 0.034%) and tannic acid (LC50, 0.022%). The mechanism of action results show that A. devastans adults treated with crude tannin of T. ornata had significantly decreased amylase, protease (p = 0.005), and invertase (p = 0.003) levels when compared with the detoxification enzymes. The levels of glycosidase, lactate dehydrogenase, esterase, lipase, invertase, and acid phosphate activities (p = 0.005) of S. wightii were reduced when compared with those of the Vijayneem and chemical pesticide Monocrotophos. In adult insects treated with LC50 concentrations of S. wightii tannin fraction 1, the total body protein (9.00 µg/µL) was significantly reduced (OT, LC50-0.019%). The SDS-PAGE analysis results also show that S. wightii tannin fraction 1 (OT and CT), fraction 2 (OT), and S. polypodioides fraction 2 (CT) had a significant effect on the total body portion level, appearance, and disappearance of some proteins and polypeptides. This study shows that the selected brown macroalgae can be utilized for the safer management of cotton leaf hoppers.

Regulation of Nanoliposome Rigidity and Bioavailability of Oligomeric Proanthocyanidin with Phytosterols Containing Different C3 Branches.

The rigidity of nanoliposomes significantly influences their physical stability and in vitro and in vivo behaviors (e.g., cellular uptake, blood circulation, biodistribution, etc.). This study aimed to quantify the rigidity of the nanoliposomes composed of phytosterol with varying C3 branches and phospholipids (DPPC, DOPC) using atomic force microscopy. Young's modulus, determined by the Shell model, effectively differentiated between mechanical differences in nanoliposomes with varying components and component structure and phase states. FTIR results indicated that P-SG exhibited the highest Young's modulus (175.98 ± 10.53 MPa) due to the hydrogen bond between the glucose residue of steryl glycosides (SGs) and the phospholipid polar head. However, the rigidity of DOPC nanoliposomes was not significantly different due to the unsaturated bond. The addition of oligomeric proanthocyanidin (OPC) did not change the order of rigidity among the nanoliposomes, with P-SG-OPC having the highest Young's modulus (126.27 ± 2.06 MPa). In the simulated gastrointestinal tract experiment, P-SG-OPC exhibited the greatest stability, with minimal particle aggregation. Cellular uptake experiments revealed that DPPC nanoliposomes with high rigidity had optimal endocytosis, while DOPC nanoliposome uptake was independent of rigidity. In melanin production inhibition tests, the inhibitory effect correlated directly with Young's modulus and P-SG-OPC had the best inhibitory effect on melanin generation. Our findings in this study provide valuable insights into the design and optimization of nanoliposomes for the efficient delivery of active substances, offering potential solutions for improving the efficacy of drug delivery systems.

Fast and Simple UPLC-Q-TOF MS Method for Determination of Bitter Flavan-3-ols and Oligomeric Proanthocyanidins: Impact of Vegetable Protein Fining Agents on Red Wine Composition.

Wine phenolic compounds, particularly proanthocyanidins (PAs), play a significant role in wine sensory characteristics, specifically bitterness and astringency. Although not consensual, flavan-3-ols and oligomeric PAs are generally considered the primary contributors to wine bitterness. Patatin, a vegetable protein fining agent, has been explored as an alternative to animal and synthetic fining agents for reducing wine bitterness. However, contradictory results exist regarding its effectiveness in removing flavan-3-ols and oligomeric PAs in red wines. In this work, a UPLC-Q-TOF MS/MS method was optimized and validated for accurately measuring flavan-3-ols, as well as dimeric and trimeric PAs, in red wines. The MS/MS analysis of flavan-3-ols, in addition to the typical fragmentation described in the literature, revealed an intense mass fragment resulting from the loss of C3O2 and C3O2 + H2O from the parent ion. It was observed that flavan-3-ols and PAs undergo oxidation during sample preparation, which was reversed by the addition of 5 g/L of ascorbic acid. The method demonstrated good linearity range (2 mg/L to 20 mg/L), detection limit (0.3 mg/L to 0.7 mg/L), quantification limit (0.8 mg/L to 2.2 mg/L), precision (repeatability 2.2% to 7.3%), and accuracy (recovery 98.5% to 100.5%). The application of patatin at different doses (5 g/L to 30 g/L) in two different red wine matrices did not reduce the levels of monomeric, dimeric, and trimeric PAs in red wines. However, similar behaviors were observed for pea protein and gelatin. Therefore, wine fining trials and efficiency measurements of the treatments in each matrix are strongly advised.

Self-assembled condensed tannins supramolecular system can adsorb cholesterol micelles to promote cholesterol excretion

In this study, the cholesterol (CH)-lowering behavioral mechanisms and drivers of condensed tannins (CTs) were revealed using a molecular aggregation theoretical model combined with in vitro experiments, as well as the CH-lowering effects of CTs validated based on animal experiments. Theoretical model results indicated that CTs can spontaneously aggregate to form supramolecular systems, can break CH micelles and form larger aggregates, a behavior driven by van der Waals forces and hydrogen bonds; DLS and TEM results confirmed that the presence of CH leads to a larger particle size of CTs and the formation of large aggregates; thermodynamic analysis and ITC revealed that the adsorption of CH by CTs is a spontaneous reaction driven by hydrogen bonds and hydrophobic forces; Animal experiments and fecal biochemical parameters further confirmed that the intake of CTs can reduce CH absorption and promotes CH excretion. Overall, this study reveals the CH-lowering behavioral mechanism of CTs from the perspective of molecular aggregation behavior.

The effects of oligomeric proanthocyanidins on hydroxychloroquine-induced retinopathy as revealed by nationwide medical claim data for South Korea.

The effects of oligomeric proanthocyanidins on hydroxychloroquine-induced retinopathy as revealed by nationwide medical claim data for South Korea.

The natural tannins oligomeric proanthocyanidins and punicalagin are potent inhibitors of infection by SARS-CoV-2.

The Coronavirus Disease 2019 (COVID-19) pandemic continues to infect people worldwide. While the vaccinated population has been increasing, the rising breakthrough infection persists in the vaccinated population. For living with the virus, the dietary guidelines to prevent virus infection are worthy of and timely to develop further. Tannic acid has been demonstrated to be an effective inhibitor of coronavirus and is under clinical trial. Here we found that two other members of the tannins family, oligomeric proanthocyanidins (OPCs) and punicalagin, are also potent inhibitors against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection with different mechanisms. OPCs and punicalagin showed inhibitory activity against omicron variants of SARS-CoV-2 infection. The water extractant of the grape seed was rich in OPCs and also exhibited the strongest inhibitory activities for viral entry of wild-type and other variants in vitro. Moreover, we evaluated the inhibitory activity of grape seed extractants (GSE) supplementation against SARS-CoV-2 viral entry in vivo and observed that serum samples from the healthy human subjects had suppressive activity against different variants of SARS-CoV-2 Vpp infection after taking GSE capsules. Our results suggest that natural tannins acted as potent inhibitors against SARS-CoV-2 infection, and GSE supplementation could serve as healthy food for infection prevention.

Inhibitory mechanism of carboxymethyl chitosan-lotus seedpod oligomeric procyanidin nanoparticles on dietary advanced glycation end products released from glycated casein during digestion

Lotus seedpod oligomeric procyanidins (LSOPC) are potent inhibitors of advanced glycation end products (AGEs), whose gastrointestinal susceptibility to degradation limits their use in vivo. In this study, carboxymethyl chitosan-lotus seedpod oligomeric procyanidin nanoparticles (CMC-LSOPC NPs) were constructed with a binding ratio of 1:6.51. CMC-LSOPC NPs significantly inhibited the release of AGEs from glycated casein (G-CS) during digestion, increasing the inhibition rate by 25.76% in the gastric phase and by 14.33% in the intestinal phase compared with LSOPC alone. To further investigate the inhibition mechanism, fluorescence microscopy, scanning electron microscopy and FTIR were used to find that CMC-LSOPC NPs could form cohesions to encapsulate G-CS in the gastric phase and hinder G-CS hydrolysis. In the intestinal phase, LSOPC was targeted for release and bound to trypsin through hydrophobic interactions and hydrogen bonding, resulting in protein peptide chain rearrangement, changes in secondary structure and significant reduction in trypsin activity. In addition, CMC-LSOPC NPs increased the antioxidant capacity of digestive fluid and could reduce the oxidative stress in the gastrointestinal tract caused by the release of AGEs. It’s the first time that CMC-LSOPC NPs were constructed to enhance the stability of LSOPC during digestion and explain the mechanism by which CMC-LSOPC NPs inhibit the release of AGEs from G-CS in both stomach and intestine. This finding will present a novel approach for reducing AGEs during gastrointestinal digestion.

Nutritional quality of indigenous legume browse in southern Ethiopia: farmers' preference and correlation of local valuation of feed value with scientific indicators.

Developing a technology for fodder trees and shrubs tailored to farmers' preferences is best done with their input, perceptions, and interests in mind. The research aimed to determine farmer preferences for indigenous legumes, fodder trees, and shrubs (ILFTS) and to examine the relationship between feed valuation and scientific parameters. A focus group discussion (FGD) was conducted with 10 farmers in each agroecological zone to determine the benchmarks for the preference ratings. The respondent farmers used the preference score sheet to rate all ILFTS on an individual basis. Twenty farmers with extensive experience in ILFTS took part in the preference score rating of each plant species in each agroecosystems. Dry matter (DM), organic matter (OM), ash, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), metabolizable energy (ME) and condensed tannin (CT) content of the samples were determined. The standard two-stage in vitro Tilley and Terry method was used to measure the in vitro dry matter digestibility (IVDMD) and in vitro organic matter digestibility (IVOMD) of samples. Digestible organic matter in dry matter (DOMD) and ME values were estimated using standard models. Analysis of variance (ANOVA) was used to analyze the variation among the species in agroecosystems. Tukey HSD tests were used for mean separation. Farmers evaluated the ILFTS using a variety of parameters, according to the study (feed value, growth rate, biomass output, compatibility, and multifunctionality). The farmers' ILFTS preference score on the evaluation criteria differed considerably (p<0.05) with species in agroecosystems. The CP, ash, and ME values of ILFTS in the study were moderate to high although exhibited a wide variation among the species in agroecosystems. The CP content was above the minimum requirement (8%) to support the normal function of rumen microorganisms. Moreover, CP content exhibited a positive significant correlation with IVDMD, IVOMD, and DOMD, unlike CT and ADL which exhibited a negative significant correlation. Conversely, the DM, OM, CP, IVDMD, IVOMD, DOMD, and ME were shown a positive significant correlation with farmers' feed value preference score, unlike the ADL and CT which exhibited a negative significant correlation. Farmers' indigenous knowledge of feed value is therefore relevant for judging the nutritive value of the ILFTS and could complement the scientific indicators.

Effects of Condensed Tannins on Bacterial and Fungal Communities during Aerobic Exposure of Sainfoin Silage.

Sainfoin is a forage legume that is widely distributed around the world and is beneficial for animals owing to the characteristics of its condensed tannins (CTs), which, from certain plants, can prolong the aerobic stability of silage. The present study investigated whether sainfoin CTs can prolong aerobic stability by adding polyethylene glycol (PEG) to inactivate CT activity in the silage system. The results showed that aerobic stability increased under the PEG treatment (p < 0.05). Ammonia nitrogen (0.71 g/kg DM vs. 0.94 g/kg DM; p < 0.05) was higher in the PEG-treated group compared with the control after 3 d of aerobic exposure. BA was detected only in the PEG-treated group upon aerobic exposure. Yeasts were more abundant in the control compared with the PEG-treated group after 7 d of aerobic exposure, after which the relative abundance of Lactobacillus was lower in the PEG-treated group (65.01% vs. 75.01% in the control; p < 0.05), while the relative abundance of Pediococcus was higher in the PEG-treated group compared with the control (10.9% vs. 4.49%, respectively; p < 0.05).The relative abundances of Apiotrichum and Aspergillus were lower in the control than in the PEG-treated group after 7 d of aerobic exposure. The results suggested that sainfoin CTs decreased aerobic stability, but could inhibit certain bacteria and fungi, such as Pediococcus and Apiotrichum, and preserve the protein content during the aerobic exposure of silage.

Oligomeric Proanthocyanidins Alleviate the Detrimental Effects of Dietary Histamine on Intestinal Health of Juvenile American Eels (Anguilla rostrata)

This study evaluated the oligomeric proanthocyanidins (OPC) on alleviating the detrimental effects in the intestine caused by dietary histamine in juvenile American eels (Anguilla rostrata). A total of 480 fish with a similar body weight of 10.84 ± 0.16 g were randomly divided into four groups, including the control group fed a basal diet, the HIS group fed a diet with a high level of histamine (534 mg/kg), the H + OPC I group fed the high histamine diet with 300 mg/kg OPC, and the H + OPC II group fed the high histamine diet with 600 mg/kg OPC. After the fish were fed the trial diets for 77 days, the intestinal samples were taken, and the related parameters were analyzed. Dietary 300 mg/kg or 600 mg/kg OPC could reverse the decreased activities of lipase, protease, and glutathione peroxidase and the level of total antioxidant capacity; the increased intestinal malondialdehyde and D-lactate acid levels and the activity of diamine oxidase in serum; and the decreased villus height caused by a high level of dietary histamine. There were no significant differences above all the indices between the H + OPC I group and the H + OPC II group. The higher relative abundances of potentially pathogenic bacteria were induced by the high level of dietary histamine. Dietary 300 mg/kg OPC might increase the relative abundance of the potential probiotics and inhibit the colonization of intestinal pathogenic bacteria. The intestinal health status of the H + OPC groups was similar to that of the control group. These results suggested that dietary 300 mg/kg OPC might alleviate the detrimental effects of dietary 534 mg/kg histamine on the intestine health of juvenile American eels by increasing the activity of digestive enzymes, improving the antioxidative potential and barrier function, and beneficially modulating the intestinal microbiota. Dietary 600 mg/kg OPC could not exert further improvement in growth performance and the intestinal health of juvenile American eels.

The effect of sodium citrate on the photolytic reaction of catechin following the addition of aluminum chloride under alkaline conditions

Tea has an abundance of aluminum and catechins. As a food additive, citrate is often added to tea. An aluminum ionic species, including its amphoteric Al3+, can be either neutral or negatively charged and exist as intermediates simultaneously in weak alkaline solutions. This study is undertaken to investigate the photolytic processes of 290 mg/L catechin hydrate (CH) upon the addition of 133 mg/L AlCl3 (CHA) and CHA in the presence of 294 mg/L sodium citrate dihydrate (CHAS) to determine the structural changes in catechin and analyze its photoproducts after blue light irradiation at 20 W/m2 in H2O at pH 8 (BLIH) via high-performance liquid chromatography equipped with a diode array detector and mass spectrometry (HPLC-DAD-MS) system. The photolytic effect of blue light on sodium citrate was also determined. When CH is treated with BLIH, A-type and B-type proanthocyanidin dimers, AtPA and BtPA, respectively, are formed by a photochemically driven redox reaction. Relative percentages of the resultant catechin are 46.3, 98.1, and 46.9 for CH, CHA, and CHAS, respectively, after BLIH treatment, suggesting that the photolysis of catechin after BLIH is suppressed by AlCl3 and that sodium citrate restores the process of the catechin-aluminum system under BLIH in alkaline conditions. The addition of AlCl3 reduces the generation of proanthocyanidins during the photolysis of catechin after the dimeric molecule is disconnected by AlCl3, which acts as a catalyst after BLIH. However, under the same conditions, the addition of sodium citrate inhibits the catalytic capacity of AlCl3, and more proanthocyanidins are generated by the catechin-aluminum system under BLIH. Sodium citrate features an inherent reducing potential to maintain the photostability of the catechin-aluminum system and inhibits the catalysis of aluminum ions in alkaline conditions under BLIH.

Ensilibility and protein degradation characteristics of forage from mountain grasslands containing tanniferous species

AbstractEnsiling forage from species‐rich mountain grasslands is challenging. Low concentrations of fermentable carbohydrates and the coarse morphological structure of the forage promote the activity of butyric acid forming bacteria. This is associated with the formation of ammonia from protein degradation, resulting in an insufficient pH decline. On the other hand, forage from species‐rich swards may contain tanniferous plant species which contain varying contents of condensed tannins (CT). Therefore, the silage quality of forage prepared from species‐rich mountain grasslands and the role CT may play in silage fermentation was studied. A set‐up of two long‐term mineral fertilization field experiments, located in the Jura mountains and the Alps in Switzerland were used to obtain forage with contrasting species and chemical composition. Collection was done during both the generative and vegetative growth stage from three differently fertilized swards: unfertilised (“0”), fertilized with phosphorus and potassium (“PK”) or fertilized with PK and nitrogen (“NPK”). The forage was wilted to approximately 37% dry matter (DM), chopped to 2 cm lengths and ensiled for at least 65 days as laboratory‐scale silages. The wilted forage was characterized by concentrations of crude protein between 117 and 130 g/kg DM and water‐soluble carbohydrates varying from 84 to 148 g/kg DM. Concentrations of CT ranged from 6 g to 14 g/kg DM and those of soluble CT from 1.8 to 7.6 g/kg DM. All silages contained butyric acid, irrespective of the type of fertilization or harvest stage (range: 1.5 g to 16 g/kg DM). Concentrations of acetic and lactic acid ranged from 2.1 g to 15.0 g/kg DM and from 21.0 to 44.0 g/kg DM, respectively. Concentrations of unfermented sugar remained high and pH levels were above those expected. Formation of non‐protein‐N (NPN) increased in the range of 130 to 264 g/kg N from wilted to ensiled forage. The negative correlations of CT or soluble CT contents with ammonia‐N or NPN in silage were found in both forage from the generative and vegetative harvests indicating a possible relationship with protein degradation during ensiling.

Effect of Condensed Tannins on Nitrogen Distribution and Metabolome after Aerobic Exposure of Sainfoin Silage

(1) Background: Previous studies have indicated that proteolysis is inhibited by the condensed tannins (CTs) that are present during sainfoin ensiling. Whether inhibiting this effect of CTs on proteolysis is functional during aerobic exposure is still unclear. (2) Methods: the present study investigated the effect of CTs on metabolite composition during the aerobic exposure of sainfoin silage via the use of polyethylene glycol (PEG), leading to the inactivation of CTs. (3) Results: The neutral detergent-insoluble protein (NDIP) and acid detergent-insoluble protein concentrations were both more concentrated in the control group than in the PEG-treated group. There were 587 and 651 different metabolites present in the control and PEG-treated groups after 3 and 7 days, respectively, of aerobic exposure of silage. Flavonoids (72 metabolites) were the most abundant among these different metabolites. The addition of PEG upregulated histidine, threonine, asparagine, tryptophan, and glutamine, but downregulated phenylalanine. The relative abundances of Lactococcus, Fructobacillus, Enterobacter, Cutibacterium, Citrobacter, and Rosenbergiella differed significantly between the control and PEG-treated groups (p &lt; 0.05); all of these bacteria showed significant correlation with some of the 50 most abundant metabolites. (4) Conclusions: the results suggest that the antioxidant status of the silage increased and inhibited the activity of a variety of bacteria that coexist with CTs, and decreased the production of certain amino acids after the aerobic exposure of silage.

Molecular Mechanism of Lotus Seedpod Oligomeric Procyanidins Inhibiting the Absorption of Oligopeptide-Advanced Glycation End Products.

Research on advanced glycation end product (AGEs) inhibition has generally focused on food processing, but many protein-AGEs will still be taken. Oligopeptide (OLP)-AGEs, as the main form after digestion, will damage human health once absorbed. Here, we investigated the ability of lotus seedpod oligomeric procyanidins (LSOPC) to inhibit the absorption of the OLP-AGEs and elucidated the underlying mechanism. Our results showed that the inhibition rate of LSOPC on the absorption of OLP-AGEs was about 50 ± 5.38%. 0.1, 0.2, and 0.3 mg/mL could upregulate the expression of ZO-1 and downregulate the expression of PepT1 and clathrin. Molecular docking showed that LSOPC could compete with the binding of OLP-AGEs to PepT1 and AP-2, thus inhibiting the absorption of OLP-AGEs. Furthermore, the interaction of LSOPC with the OLP-AGEs reduced the surface hydrophobicity of OLP-AGEs. It altered the secondary structure of the OLP-AGEs, thus weakening the affinity of the OLP-AGEs to the transporter protein to inhibit the absorption of OLP-AGEs. Together, our data revealed potential mechanisms by which LSOPC inhibit the absorption of OLP-AGEs and opened up new perspectives on the application of LSOPC in reducing the increasing health risks posed by OLP-AGEs.

Ultra-stretchable, tissue-adhesive, shape-adaptive, self-healing, on-demand removable hydrogel dressings with multiple functions for infected wound healing in regions of high mobility.

Bacterial infection in the most mobile area usually leads to delayed healing and functional restriction, which has been a long-term challenge in clinic. Developing hydrogel-based dressings with mechanical flexibly, high adhesive and anti-bacterial properties, will contribute to the healing and therapeutic effects especially for this typical skin wound. In this work, composite hydrogel named PBOF through multi-reversible bonds between polyvinyl alcohol, borax, oligomeric procyanidin and ferric ion demonstrated a 100 times ultra-stretch ability, 24 kPa of highly tissue-adhesive, rapid shape-adaptability within 2 min and self-healing feature within 40 s, was designed as the multifunctional wound dressing for the Staphylococcus aureus-infected skin wound in the mice nape model. Besides, this hydrogel dressing could be easily removed on-demand within 10 min by water. The rapid disassembly of this hydrogel is related to the formation of hydrogen bonds between polyvinyl alcohol and water. Moreover, the multifunctional properties of this hydrogel include strong anti-oxidative, anti-bacteria and hemostasis derived from oligomeric procyanidin and photothermal effect of ferric ion/polyphenol chelate. The killing ratio of the hydrogel on Staphylococcus aureus in infected skin wound reached 90.6% when exposed to 808 nm irradiation for 10 min. Simultaneously, reduced oxidative stress, suppressed inflammation, and promoted angiogenesis all together accelerated wound healing. Therefore, this well-designed multifunctional PBOF hydrogel holds great promise as skin wound dressing especially in the high mobile regions of the body. STATEMENT OF SIGNIFICANCE: An ultra-stretchable, highly tissue-adhesive, and rapidly shape-adaptive, self-healing and on-demand removable hydrogel based on multi-reversible bonds among polyvinyl alcohol, borax, oligomeric procyanidin and ferric ion is designed as dressing material for infected wound healing in the movable nape. The rapid on-demand removal of the hydrogel relates to the formation of hydrogen bonds between polyvinyl alcohol and water. This hydrogel dressing shows strong antioxidant capacity, rapid hemostasis and photothermal antibacterial ability. This is derived from oligomeric procyanidin and thephotothermal effect of ferric ion/polyphenol chelate, which eliminates bacterial infection, reduces oxidative stress, regulates inflammation, promotes angiogenesis, and finally accelerates the infected wound healing in movable part.

The role of Arabic gum on astringency by modulating the polyphenol fraction-protein reaction in model wine.

The potential contribution of Arabic gum to wine astringency was discussed in this study. Two universally used Arabic gum (concentration of 0.2-1.2g/L) were investigated in model wine based on the polyphenol fractions (phenolic acids, monomeric/oligomeric, and polymeric procyanidin) and protein interaction system. Both physicochemical analyses and sensory evaluation revealed that the modulation of Arabic gum on astringency was affected by the structural properties and concentration of Arabic gum and polyphenolic fractions. Arabic gum at 0.2g/L appeared as the optimal dose to reduce astringency compared to 0.6 and 1.2g/L. It inhibited astringency induced by polymeric procyanidin more than that of oligomeric procyanidins and phenolic acids mainly by forming soluble ternary complexes with polyphenols and proteins, and preferentially binding proteins/polyphenols to decrease polyphenol-protein reactions. Arabic gum also inhibited the self-aggregation of polyphenols, exhibiting more binding sites when its higher molecular weight and more/longer branches, leading to competition with polyphenols for bind proteins.