Condensed Tannins Research Articles

Oligomeric proanthocyanidin ameliorates sepsis-associated renal tubular injury: involvement of oxidative stress, inflammation, PI3K/AKT and NFκB signaling pathways.

Sepsis is a potentially fatal infectious disease that easily causes shock and numerous organ failures. The kidney is one of the most susceptible to injury. Early intervention and renal protection significantly minimize patient mortality. Oligomeric proanthocyanidin (OPC), a naturally occurring plant compound, has a high potential for renal protection. This study was aimed at exploring the potential renoprotective role of OPC in sepsis-related renal tubular injury. C57/B6 mice were intraperitoneally injected with lipopolysaccharide (LPS) to simulate sepsis-related acute kidney injury in vivo. Renal function and pathology were assessed. RNA sequencing examined OPC mechanisms against LPS-induced renal injury. Oxidative stress indicators and inflammatory cytokines in blood serum and renal tissues were evaluated. In vitro, MTT assays assess cell viability. Apoptosis cells were detected using Hoechst 33342 and propidium iodide staining. Western blot assessed PI3K/AKT and NFκB signaling pathway proteins. OPC reduced LPS-induced renal tubular injury, improved renal functions and pathological changes, restored glutathione content, superoxide dismutase activity, and catalase activity, inhibited malondialdehyde overproduction, and suppressed LPS-induced overproduction of pro-inflammatory cytokines and the decline of anti-inflammatory cytokines. OPC attenuated LPS-induced cell morphological injury, reduced cell viability loss, and recovered the changes in proteins involved in PI3K/AKT and NFκB signaling pathways in MTEC cells. OPC protects against LPSinduced renal tubular injury by counteracting oxidative stress, inhibiting inflammatory responses, activating the PI3K/AKT signaling pathway, and inhibiting the NFκB signaling pathway. It may provide a viable solution to lessen renal injury in patients with sepsis.

Traditional Use, Chemical Constituents, and Pharmacological Activity of Maytenus elaeodendroides Stem Bark

Plants belonging to the genus Maytenus are members of the Celastraceae family. They have been widely used by different peoples as treatment for curing many diseases. The aim of this study was to explore the anti-inflammatory and antioxidant properties of Maytenus elaeodendroides stem bark extracts, an endemic Cuban plant. The antioxidant activity of four extracts (EtOH, EtOAc, n-BuOH, and diethyl ether/petroleum ether 1:1) was determined using DPPH and FRAP methods. Meanwhile, anti-inflammatory effects by the edema method were induced by croton oil in the mouse ear. The investigated extracts showed radical reduction capacity and prevented ear inflammation at doses of 4 mg/ear. In addition, FIA/ESI/IT/MSn was used to determine the qualitative chemical composition of the EtOAc extract and allowed the identification of five flavan-3-ol monomers, four dimers, and other proanthocyanidin oligomers. From this extract three flavan-3-ol compounds (elaeocyanidin and 4′-O-methylgallocatechin), one of them new (2′-hydroxy-4′-methoxy-epigallocatechin), and a proanthocyanidin dimer (afzelechin-(4β→8)-4′-O-methylepigallocatechin) were isolated and identified by the chromatographic method and spectroscopic techniques, mainly ESI-MS and NMR spectroscopic methods.

Biosynthesis-Based Spatial Metabolome of Condensed Tannin Reveals Its Role in Salt Tolerance of Non-Salt-Secretor Mangrove Kandelia obovata.

An autofluorescent inclusion (AFI) specifically accumulated in mesophyll cells (MCs) of non-salt-secretor mangrove was found to be related to salt, but its biosynthesis and spatial distribution characteristics remain unclear. Here, Kandelia obovata served as the experimental material, and the composition of AFI was identified as condensed tannin (CT). Na contents increased in purified AFIs under NaCl treatment, while Na+ efflux in MCs was lower than the control. In vitro, Na+ addition caused aggregations of AFIs. Proteins related to Na+/H+ and vesicle transport were identified in the purified AFIs by liquid chromatography-mass spectrometry. TEM images revealed the structures involved in CT biosynthesis in chloroplasts and CT accretions in vacuoles were more visible under higher salinity. Spatial metabolomics analysis on flavonoid metabolites involving in CT biosynthesis illustrated those flavonoids and three CT monomers were positively related to salt in MCs. Real-time quantitative PCR verified the genes encoding enzymes for CT biosynthesis were upregulated accordingly. Taken together, CT biosynthesis is positively correlated with Na accumulation in leaves. The CTs synthesized in chloroplasts are transported as shuttles to vacuole via cytoplasm, facilitating the sequestration and compartmentalization of excessive Na+ ions into the vacuole, which confers non-salt-secretor mangrove K. obovata a higher salt tolerance.

Analysis of Adverse Reactions Associated with the Use of Crataegus-Containing Herbal Products

Background/Objectives: Products from various parts of Crataegus species are traditionally applied as a cardiotonic. In Europe and the USA, mainly Crataegus monogyna Jacq. (Lindm.) and Crataegus laevigata (Poir.) DC (synonym Crataegus oxyacantha L.) are used, but worldwide, other Crataegus species are also used. Phytotherapeutic preparations with a standardised content of flavonoids and/or oligomeric procyanidins are commercially available. The products are generally considered as safe and are at most associated with minor and atypical adverse reactions. The aim of this study was to critically assess the information about the safety of Crataegus-containing products in humans. Methods: A scoping review of the literature about adverse reactions associated with Crataegus-containing products was performed. Next, individual case safety reports (ICSRs) were assessed, which were included in VigiBase (the World Health Organisation’s global database of adverse event reports for medicines and vaccines) and in the database of the Netherlands Pharmacovigilance Centre Lareb. The findings are discussed in relation to the literature. Results: The scoping review yielded 23 clinical studies with single-herb and 14 with multi-herb preparations, from which only a few minor gastrointestinal and cardiac events had been reported. A total of 1527 reports from VigiBase, from 1970 to 2023, were analysed, as well as 13 reports from Lareb. The most frequently reported adverse reactions belonged to the system organ classes ‘gastrointestinal disorders’, ‘skin and subcutaneous tissue disorders’, ‘general disorders and administration site conditions’, ‘cardiac disorders’ or ‘nervous system disorders’. In 277 reports of VigiBase, a single-herb product was the only suspect for causing the adverse reaction(s). Of these, 12.6% were graded as serious. Conclusions: The results of our study provide deeper insight in the adverse reaction profile of Crataegus-containing products and should contribute to their safe application in the treatment of less severe forms of cardiac failure.

Combined treatment with Aronia berry extract and oligomeric proanthocyanidins exhibit a synergistic anticancer efficacy through LMNB1-AKT signaling pathways in colorectal cancer.

Colorectal cancer (CRC) is one of the most prevalent and highly recurrent malignancies worldwide and currently ranks as the second leading cause of cancer-related deaths. The high degree of morbidity and mortality associated with CRC is primarily attributed to the limited effectiveness of current therapeutic approaches and the emergence of chemoresistance to standard treatment modalities. Recent research indicates that several natural products, including Aronia berry extracts (ABE) and oligomeric proanthocyanidins (OPCs), might offer a safe, cost-effective, and multitargeted adjunctive role to cancer treatment. Herein, we hypothesized a combined treatment with ABE and OPCs could synergistically modulate multiple oncogenic pathways in CRC, thereby enhancing their anticancer activity. We initially conducted a series of in vitro experiments to assess the synergistic anticancer effects of ABE and OPCs on CRC cell lines. We demonstrate that these two compounds exhibited a superior synergistic anticancer potential versus individual treatments in enhancing the ability to inhibit cell viability, suppress colony formation, and induce apoptosis (p < 0.05). Consistent with our in vitro findings, we validated this combinatorial anticancer effect in tumor-derived 3D organoids (PDOs; p < 0.01). Using genome-wide transcriptomic profiling, we identified that a specific gene, LMNB1, associated with the cell apoptosis pathway, was found to play a crucial role in exhibiting anticancer effects with these two products. Furthermore, the combined treatment of ABE and OPCs significantly impacted the expression of key proteins involved in apoptosis, including suppressed expression levels of LMNB1 in CRC cell lines (p < 0.05), which resulted in inhibiting downstream AKT phosphorylation. In conclusion, our study provides novel evidence of the synergistic anticancer effects of ABE and OPCs in CRC cells, partially mediated through the regulation of apoptosis and the oncogene LMNB1 within the AKT signaling pathway. These findings have the potential to better appreciate the anticancer potential of natural products in CRC and help improve treatment outcomes in this malignancy.

Condensed tannins from black wattle as a promising nutritional additive for Nile tilapia: growth, immune and antioxidant responses, and gut morphology

The present study aimed to investigate the potential of condensed tannins (CT), derived from black wattle (Acacia mearnsii) tree bark, as a nutritional additive for Nile tilapia (Oreochromis niloticus) juveniles. CT are known for their antioxidant and immune-modulating properties, and their inclusion in aquafeeds may enhance fish health and performance. In this study, six diets were formulated: one control diet (Con) with no additives, and five experimental diets supplemented with CT extract at concentrations of 150, 250, 500, 750, and 1000mg/kg (CT150, CT250, CT500, CT750, CT1000, respectively). The selection of these doses was based on previous studies indicating that lower concentrations (below 1000mg/kg of diet) of tannins may offer benefits, while higher concentrations could exhibit antinutritional effects. After a 90-day feeding trial, fish fed the CT150 diet exhibited significantly higher growth compared to the control group. Additionally, fish in the CT150 group showed higher plasma lysozyme activity, while myeloperoxidase activity and hemolytic activity of the complement system were significantly higher in all tannin-fed groups compared to the control. Notably, CT150-fed fish demonstrated liver antioxidant responses comparable to or better than the control group, with no significant increase in lipid peroxidation, suggesting antioxidant protection. Histological analysis revealed a significant increase in intestinal villi density in the CT150 and CT500 groups compared to the control. While all groups showed an increase in absorption surface area (ASA), this increase was statistically significant only in the CT250, CT500, and CT750 groups when compared to the control. Furthermore, the CT150 diet led to the highest survival rate (80%) following a bacterial challenge. These findings suggest that dietary supplementation with 150mg/kg of CT from black wattle bark provides the most beneficial effects on growth, immune response, and survival in Nile tilapia juveniles.

The synergistic enhancement or inhibition of different molecular weight components of mannoproteins after ultrafiltration on the encapsulation.

This study investigated the effects of molecular weight regulation on mannoproteins (MPs) in encapsulating both monomeric and oligomeric proanthocyanidins (MOPC). To achieve this, two different conformations of MPs were fractionated by ultrafiltration into two main molecular weight components. The results indicated that regulating molecular weight through ultrafiltration altered the conformation of MPs chains, which in turn affected the intermolecular forces with MOPC. Specifically, the interactions among the different molecular weight components of MPs formed a cross-linking network. High molecular weight components provided external support to this network, while low molecular weight components contributed to internal stabilization. The dense, flexible, and irregular coil structure of MPs facilitated the entry of MOPC into the internal spaces of the cross-linking network. Additionally, protein unfolding into a more stable β-sheet structure further stabilized MPs' cross-linking network, enhancing its capacity to encapsulate MOPC. The presence of more hydrophobic regions and positive charges within the proteins increased the number of binding sites for MOPC. This study aimed to identify the primary structural forms of MPs with potent initial bitter inhibition capabilities on MOPC, and a proposed ultrafiltration method was introduced to modify the triple helix structure of polysaccharide, offering a foundational theoretical framework for enhancing the functional attributes of current or prospective MPs. Additionally, the mixed regulation of polysaccharides with varying conformations was also beneficial for guiding the production of high-efficiency polysaccharide products.

Extraction and In Vitro and In Vivo Antioxidant Activity Evaluation of Polyphenols from Lychee Pericarp

Background Finding a new promising plant antioxidant to combat or prevent cardiovascular disease remains a major challenge for researchers. Lychee pericarp, which includes a variety of polyphenols, is a prospective source of botanical antioxidants. Purpose In response to this issue, we assessed the effect of lychee bark extract on oxygen radical scavenging capacity and separate vascular protective ability in vivo. Methods In the current study, the lychee pericarp enrichment product (RLP) was obtained by optimizing an extraction method and separated using modern separation methods. The structure of the isolated compounds was assessed using 1H-NMR, 13C-NMR, and electrospray ionization-mass spectrometry, and the content of polyphenols obtained from the extract was quantified using the area normalization method. In addition, the capacity of RLP to scavenge oxygen radicals in vitro was assessed using the DPPH (1,1-diphenyl-2-picrylhydrazyl) and T-AOC (total antioxidant capacity) techniques. Furthermore, an isoprenaline hydrochloride (ISO)-induced rat model of acute myocardial ischemia was established, and four biochemical indicators were used to assess the effect of lychee bark extract on oxygen radical scavenging capacity and cardiovascular protective ability in vivo. Results RLP extraction produced 11 chemicals, 6 of which were structurally assessed. Quantitative analysis revealed that epicatechin, PC-C(epicatechin-(4β↓8,2β↓O↓7)-epicatechin-(4β↓8)-epicatechin), type A proanthocyanidin trimer, proanthocyanidin A2, and type B proanthocyanidin dimer were the most abundant polyphenols. The in vitro DPPH and T-AOC findings revealed that RLP exhibited strong free radical scavenging activity, approximately 1.5-fold that of vitamin C. The four biochemical indicators confirmed the antioxidant activity and cardiovascular protective ability of RLP in vivo. Conclusion RLP has good in vivo and in vitro antioxidant activity, confirming lychee pericarp as a prospective source of botanical antioxidants.

Comparative Evaluation of Enzymatic Crude Protein Degradation in Selected Legume Forages

For protein evaluation of feedstuffs for ruminants, the Streptomyces griseus protease test offers a purely enzymatic approach to estimate ruminal protein degradation. This study was conducted to determine the enzymatic crude protein (CP) degradability of alfalfa, sainfoin, and common vetch hays, which are commonly used in ruminant nutrition. To estimate CP degradation, fifteen samples from each type of hay were incubated in vitro with a commercial protease extracted from Streptomyces griseus. The incubation was carried out for 1, 4, 24, and 48 hours in a borate-phosphate buffer at pH 8. Significant differences in CP degradability values were found among all three types of hay across all incubation periods. For all incubation periods, sainfoin had the lowest CP degradability values (P &lt; 0.05), due to its high content of cell wall components and condensed tannins (CTs). For incubation periods longer than 1 hour, common vetch had the highest CP degradability values, followed by alfalfa and sainfoin, respectively (P &lt; 0.05). As a result, the use of the protease enzyme extracted from Streptomyces griseus was confirmed as an effective method for estimating the CP degradability of selected legume forages in the laboratory, eliminating the need for animal testing. However, since plant proteins are often embedded within carbohydrate complexes, it is recommended that future tests consider the combined use of protease and carbohydrase, particularly for sainfoin, which is rich in cell wall components and condensed tannins.

In Vitro Mechanistic Studies of a Standardized Sustainable Grape Seed Extract for Potential Application as a Mood-Modulating and Cognition-Enhancing Supplement

Background: Grape seed extract (GSE) from Vitis vinifera L. is rich in polyphenols and oligomeric proanthocyanidin complexes (OPCs), and it has shown potential benefits in managing low mood and cognitive function. In this study, we investigated the potential bioactivities of Enovita®, a standardized GSE extract (GSEe herein) rich in OPCs, in key mechanistic pathways related to low mood conditions and cognitive function. Methods: In vitro assays were conducted to assess GSEe’s inhibitory effects on γ-aminobutyric acid transaminase (GABA-T) and monoamine oxidase A (MAO-A), its binding affinity to the GABA site of GABA-A receptors, and its effects on acetylcholinesterase (AChE). Its neuroprotective effects on human SH-SY5Y neuroblastoma cells under oxidative stress (induced by H2O2) were assessed using MTT and LDH release assays. Its antioxidant activities were evaluated using DPPH, ABTS, FRAP, ORAC, HORAC, total phenolic content, and TAS assays. Its cytotoxicity was also evaluated. Results: GSEe showed significant GABA-T inhibitory activity. It also exhibited MAO-A and AChE inhibition, along with moderate binding affinity to the GABA-A receptor. In neuroprotective assays, GSEe provided significant protection to SH-SY5Y cells against oxidative stress. GSEe demonstrated robust antioxidant activity in all assays, including scavenging of DPPH and ABTS radicals, high ferric-reducing power, high polyphenolic contents, and a substantial total antioxidant capacity. Conclusions: GSEe exhibits promising bioactivities, highlighting its potential as a supplement for modulating mood and enhancing cognitive function. Overall, the promising results from these in vitro studies provide a strong foundation for the continued exploration and development of GSEe as a viable natural supplement for enhancing mental health and cognitive function.

Potential Benefits of Tannins on Ruminant Health, Production and Environmental Sustainability

Tannins are naturally occurring polyphenolic compounds increasingly recognized for their potential benefits to ruminants. Tannins can be extracted from plants' roots, bark, leaves, and seed husks. Management of plant communities to produce a diverse array of secondary compounds, particularly tannins, is a promising strategy for holistically enhancing agroecosystems on rangelands and benefiting free grazing ruminant animals. Deterioration of rangelands constrains plant diversity, reducing tanniferous forage plants and limiting tannin availability to free-grazing ruminants. Ruminants supplemented with tannin extracts in confined feeding operations have gained several reported benefits. Commercial industries are also expanding to extract and process tannin extracts. The beneficial effects of tannins depend on many factors, including plant species, plant part, tannin type (condensed tannins (CTs) or hydrolyzable tannins (HTs), and dose. Tannin binds with proteins, enhances the diversity and abundance of amino acids in the small intestine, and improves overall protein absorption and utilization. Compiled with other mechanisms, tannins can improve the quality, quantity, shelf life, and consumer preference of meat and milk products. Tannins also possess antimicrobial, anti-parasitic, antioxidant, immunomodulatory, and anti-inflammatory properties. CTs also impact rumen microbial populations, decreasing methane production, improving ruminal microbiota diversity, and lowering ammonia nitrogen production. Therefore, the use of tannin from tannin extracts and tanniferous forage plants presents a promising avenue for enhancing confined and free-grazing ruminant animals' health, productivity, and environmental sustainability.

Extraction and structural analysis of mannoproteins from different species of yeast: Bitter suppression and the potential mechanisms for wine

To rich the research for mannoproteins (MPs) suppressive effect on the bitterness of wine, this study distinguished bitterness into initial bitterness and bitter aftertaste. By utilizing the thermal alkali extraction method, MPs were extracted from three different yeast species: Saccharomyces cerevisiae (CECA), Lachancea thermotolerans (A38), and Torulaspora delbrueckii (2082). Their basic structures, addition concentrations, and correlation with bitter suppression ability were characterized. CECA exhibited stronger initial bitterness suppression ability, may attributed to its more branches and lack of a triple-helix structure. 2082 showed greater bitter aftertaste suppression and might due to smaller particle aggregation, fewer branches, and triple-helix structure. Additionally, it was noteworthy that due to the unique structure of 2082, it may bound more monomer and oligomeric proanthocyanidins (MOPC) on MPs surface, reducing its initial bitterness suppression ability. Concerning concentration, the increase in polysaccharide chain polymerization hindered further interaction with MOPC, leading to a decrease in its initial bitterness suppression ability. Bitter aftertaste exhibited different behaviors. As the concentration of CECA increased, there was an increase in oral adhesion instead.

Proteomic Profiling in Pediococcus pentosaceus SF11 Exposed to Condensed Tannins from Sainfoin.

The antibacterial mechanism of condensed tannins (CTs) obtained from tea has been elucidated, but the mechanism of legume-derived CTs remains unclear. The mechanisms of legume- and tea-derived CTs probably differ due to the diverse compositions of CTs. Previous research found that sainfoin CTs directly inhibited the growth of Pediococcus. The present study investigated the inhibition mechanism of CTs against Pediococcus pentosaceus SF11 (SF11) through proteomic analysis. The results showed that the minimum inhibitory concentration (MIC) of CTs against SF11 was 1500 mg/L and that CTs increased cell membrane permeability in a dose-dependent manner. In total, 418 differentially expressed proteins (DEPs) were identified between the CT treatment and the control, among which 341 were down-regulated and 77 were up-regulated in the CT treatment. The protein interaction network showed that the expression of only two DEPs was highly different between CT treated and control (|log2FC|> 2); the atpD protein was up-regulated in the CT-treated group, which was involved in ATP synthesis; down-regulated DEPs were most involved in lipoteichoic acid synthesis, peptidoglycan synthesis, and glycine metabolism. Twenty-seven proteins were not detected after CT treatment, which were involved in functions including fatty acid synthesis, RNA synthesis and translation, drug resistance, and cell membrane permeability in SF11. Therefore, the findings suggest that the inhibition mechanism of CTs may be related to cell membrane damage and inhibition of cell reproduction.

Condensed tannin improves growth and alleviates intestinal inflammation of juvenile largemouth bass (Micropterus salmoides) fed with high cottonseed protein concentrate diet

The objective of this study was to examine the potential of condensed tannin (CT) in mitigating the adverse effects on growth and intestinal health induced by high cottonseed concentrate protein (CPC) diets in juvenile largemouth bass (Micropterus salmoides). Largemouth bass were respectively fed with the basic diet, the high CPC diet, and the CPC + CT diet (incorporated 3.75 g/kg CT into the high CPC diet) for a duration of 8 weeks. Results indicated that the high CPC diet resulted in decreased growth performance and compromised intestinal health. Dietary CT enhanced the growth of fish, improved intestinal function, and optimized intestinal microbiota. Additionally, intestinal transcriptome analysis revealed that dietary CT might mitigate intestinal inflammation by downregulating the related gene expression in the cell adhesion molecule pathway. Furthermore, the gene expression of cd22 and mhc2 was positively correlated with the relative abundance of the Geodermatophilus, an indicator species of intestinal microbiota in high CPC treatment. Our research suggests that the inclusion of CT (3.75 g/kg) in the high CPC diet of largemouth bass can stimulate growth and alleviate negative impacts on intestinal health, indicating that CT can be utilized to enhance the utilization of CPC in fish nutrition.

AIM/NBO Analysis of the Geminal Coupling Constants in the Stabilization of A-Type Dimeric Proanthocyanidin: Angular Dependence.

The angular dependence of the indirect short-range spin-spin coupling constants (SSCC), the geminal , , and in A-type dimeric proanthocyanidin, was investigated using density functional theory. We studied the rotation of ring B around the bond. Therefore, we calculated hyperconjugative charge transfers and bond polarizations within the natural bond orbital (NBO) approach, performing a topological study based on Bader's theory, AIM (atoms in molecules), and analyzing the angular dependence of AIM/NBO parameters. The results describe a relationship between the geminal coupling that changes with angular variation and NBO charge transfers to the bonds involved in the coupling pathways that can explain the behavior of the former property. Based on AIM/NBO data, inductive and mesomeric effects were described and quantified, showing a clear correlation with the stabilization of the structure, demonstrating a resonance-assisted inductive effect. We also set out strong hyperconjugative interactions (anomeric effect) involving nonbonding electron pairs of oxygen atoms. This analysis of coupling constants supports previous models by other authors and shows the application in this particular case. Moreover, the SSCCs studied herein are used for identifying stable structures and conformational search analysis of flavonoids. Finally, our results show the relationship between SSCCs and the structure stabilization and charge delocalization effects.

Dietary condensed tannin supplementation improves growth performance and feed utilization of juvenile Largemouth bass (Micropterus salmoides) through positively regulating serum lipids and intestinal health

Considering the diverse biological activities of condensed tannin (CT), the study aimed to evaluate the effect of CT on growth performance and intestinal health in juvenile largemouth bass (Micropterus salmoides) through a 56-day feeding trial. Largemouth bass (5.99 ± 0.03 g) were fed a basic diet supplemented with different levels of CT: 0 g/kg (the control group, CG), 0.60 g/kg (the T0.6 group), 1.50 g/kg (the T1.5 group), 3.75 g/kg (the T3.75 group), and 9.38 g/kg (the T9.38 group). The results indicated that dietary supplementation of CT at 3.75 g/kg promoted growth performance, feed conversion ratio, the apparent digestibility coefficients (ADCs) of crude protein and crude lipid, the crude protein of whole-body, the intestinal antioxidant capacity, and intestinal immune response, as well as the development of intestinal villi (P < 0.05), while the fish fed with 9.38 g/kg CT exhibited the opposite trend. Further, dietary CT (3.75 g/kg) decreased crude lipid in the whole-body compared to the CG (P < 0.05). Dietary CT (3.75 g/kg) altered the microbial community, the relative abundance of Bacillus and Lysinibacillus were increased compared to the CG. Additionally, the serum metabolome results revealed a negative correlation between Lysinibacillus abundance and lipid metabolites in the serum. These findings suggested that supplementing the diet with 3.75 g/kg CT promoted the growth performance, feed utilization, and intestinal health of largemouth bass. The optimum CT level was 4.15 g/kg based on second-order polynomial regression analyses of weight gain rate.

Investigating the effects of thermal processing on bitter substances in atemoya (Annona cherimola × Annona squamosa) through sensory-guided separation

Atemoya (Annona cherimola × Annona squamosa) is a specialty crop in Taiwan. Thermal treatment induces bitterness, complicating seasonal production adjustments and surplus reduction. In this research, sensory-guided separation, metabolomics, and orthogonal partial least squares discrimination analysis (OPLS-DA) are used for identifying the bitterness in atemoya which originates from catechins, epicatechin trimers, and proanthocyanidins. Different thermal treatments (65 °C, 75 °C, and 85 °C) revealed that the glucose and fructose contents in atemoya significantly decreased, while total phenols, flavonoids, and tannins significantly increased. The concentration of 5-hydroxymethylfurfural (5-HMF) increased from 23.16 ng/g in untreated samples to 400.71 ng/g (AP-65), 1208.59 ng/g (AP-75), and 2838.51 ng/g (AP-85). However, these levels are below the 5-HMF bitterness threshold of 3780 ng/g. Combining mass spectrometry analysis with sensory evaluation, OPLS-DA revealed that atemoya treated at 65 °C, 75 °C, and 85 °C exhibited significant bitterness, with the main bitter components being proanthocyanidin dimers and trimers.

Oligomeric procyanidins combined with Parabacteroides distasonis ameliorate high-fat diet-induced atherosclerosis by regulating lipid metabolism, inflammation reaction and bile acid metabolism in ApoE−/− mice

Atherosclerosis (AS) is the main pathological basis of cardiovascular diseases. Hence, the prevention and treatment strategies of AS have attracted great research attention. As a potential probiotic, Pararabacteroides distasonis has a positive regulatory effect on lipid metabolism and bile acids (BAs) profile. Oligomeric procyanidins have been confirmed to be conducive to the prevention and treatment of AS, whose anti-atherosclerotic effect may be associated with the promotion of gut probiotics. However, it remains unclear whether and how oligomeric procyanidins and P. distasonis combined (PPC) treatment can effectively alleviate high-fat diet (HFD)-induced AS. In this study, PPC treatment was found to significantly decrease atherosclerotic lesion, as well as alleviate the lipid metabolism disorder, inflammation and oxidative stress injury in ApoE−/− mice. Surprisingly, targeted metabolomics demonstrated that PPC intervention altered the BA profile in mice by regulating the ratio of secondary BAs to primary BAs, and increased fecal BAs excretion. Further, quantitative polymerase chain reaction (qPCR) analysis showed that PPC intervention facilitated reverse cholesterol transport by upregulating Srb1 expression; In addition, PPC intervention promoted BA synthesis from cholesterol in liver by upregulating Cyp7a1 expression via suppression of the farnesoid X receptor (FXR) pathway, thus exhibiting a significant serum cholesterol-lowering effect. In summary, PPC attenuated HFD-induced AS in ApoE−/− mice, which provides new insights into the design of novel and efficient anti-atherosclerotic strategies to prevent AS based on probiotics and prebiotics.

Conformational preferences of cocoa oligomeric proanthocyanidins and their influence on polarity

Proanthocyanidins (OPACs) are the second largest class of plant metabolites after lignans. Although knowledge of their 3D conformations would add greatly to our understanding of their biological properties, very little has been published on the conformations of OPACs with a degree of polymerization (DP) above 4. We investigated the conformations of the linear epicatechin oligomers, prominent representatives of OPACs prevalent in apples and cocoa, where the epicatechin units are interconnected through the 4β-8 bonds. For DP-2 to DP-10 oligomers, conformational preferences reflected in the arrangement of consecutive flavan-3-ol units, are characterized by the φ torsion. For dimers, there are two energy wells corresponding to two preferred φ torsions, designated as compact and extended form. This behaviour is preserved in OPACs with higher DPs, but the most energetically favoured conformations are a combination of both, with compact-only or extended-only conformations being very unlikely. Thus, oligomers with DP ≥ 7 tend to assume an overall conformation approximating a spherical shape. This shape has a significant influence on the polarity of the OPAC oligomers expressed as 3D polar surface area, calculated using Spartan software for geometry-optimized 3D models, and possibly on other physicochemical properties. The results of polarity calculations provide a molecular-level rationale for the polarity-based chromatographic separation of the cocoa B-type procyanidins with DP range 4 to 10. In our experiments, using centrifugal partition chromatography (CPC) (a solvent system consisting of EtOAc-EtOH-water (6:1:5) v/v/v with aqueous phase stationary and upper phase mobile) we found that an enriched mixture of proanthocyanidins eluted first DP-1 (epicatechin) followed by consecutive elution of the DP-2 to DP-10 in the linear 4β-8 form. We demonstrated that such separation would not be possible if compact-only or extended-only conformations were present in solution. However, for the energy-favoured, spherically shaped conformations, the observed CPC elution order is fully justified.

A bio-functional cryogel with antioxidant activity for potential application in bone tissue repairing

Antioxidant and free radical resistance has been a key concern of tissue engineering. In this study, Hydroxyapatite (HAp) with osteogenic activity and Oligomeric Proantho Cyanidins (OPC) with antioxidant activity were chemically grafted to prepare gelatin-based biofunctional aerogel (GHPOS). SEM results confirmed that these aerogels exhibited obvious macroporous structure and could provide a suitable microenvironment for bone cell growth. The addition of HAP-PEI-OPC made it have good antioxidant activity, and the cell results proved that the aerogel prepared in this study had good cytocompatibility and did not produce cytotoxicity. The addition of nanoparticles played an important role in the activity of 3T3-E1. The results showed that these bioactive aerogel scaffolds have potential applications in bone tissue engineering.