Search Results (111)

Tannins are key compounds determining the astringency of walnuts. Elucidating the structural characteristics of tannin cells in walnut inner seed coats and the accumulation patterns of esterified catechins (e.g., EGCG and ECG) is of significant importance for both quality regulation of walnuts and the high-value utilization of tannin resources. However, the enzymatic properties and biological functions of walnut tannases (JrTAs) have not been systematically investigated. Thus, the enzymatic characteristics of walnut tannase and its hydrolytic function on tannin-like substances were analyzed. It showed that tannin accumulation in the inner seed coat of ‘Nonghe 1’ walnut was closely associated with the development of tannin cells. During seed coats development, the total tannin content initially decreased and then increased, while the levels of monomeric phenolics related to tannin synthesis (GC, EGC and EC) continuously increased. Two walnut tannase genes, JrTA1 and JrTA2, were cloned and the recombinant proteins were purified. In vitro enzymatic activity tests confirmed that both enzymes effectively hydrolyzed ester-type catechins ECG and EGCG after 20 min of reaction at 40 °C and pH 7.0. Moreover, the transgenic Arabidopsis systems and green tea infusion study demonstrated that JrTA1 and JrTA2 retained their ability to specifically cleave the ester bonds of ester-type catechins in heterologous systems, achieving efficient tannin degradation. This study systematically elucidates the enzymatic functions of JrTAs, which provides a theoretical foundation for the further development and application of walnut tannases. Full article

Background/Objectives: Bauhinia cheilantha Bong. Steud. (Leguminosae; “pata-de-vaca”) is traditionally used in folk medicine for its antidiabetic, anti-inflammatory, and sedative properties. This study aimed to evaluate aqueous leaf extracts of B. cheilantha, non-delipidated and delipidated, regarding their phytochemical composition, phenolic profile, antioxidant potential, and cytotoxic, genotoxic, and antigenotoxic effects. Methods: Phytochemical screening was performed by TLC, and phenolic compounds were determined by HPLC. Antioxidant activity was assessed using DPPH, ABTS, and phosphomolybdenum assays. Cytotoxicity, genotoxicity, and antigenotoxicity were evaluated in L929 murine fibroblast cells using MTT and cytokinesis-block micronucleus (CBMN) assays. Results: Both extracts contained anthocyanins, phenolics, lignans, saponins, and hydrolyzable tannins. The delipidated extract showed higher total phenolic content (17.54 mg/kg) than the non-delipidated (13.76 mg/kg). Major constituents included kaempferol 3-glucoside, quercetin, hesperidin, naringenin, and t-cinnamic acid. Antioxidant assays revealed EC₅₀ values of 25.84, 13.60, and 66.09 µg/mL for the non-delipidated extract, and 26.19, 16.34, and 52.78 µg/mL for the delipidated extract in the DPPH, ABTS, and phosphomolybdenum assays, respectively. No cytotoxicity was observed, except at 1600 µg/mL for the non-delipidated extract and 800–1600 µg/mL for the delipidated extract. Genotoxicity occurred only at 400 µg/mL. Antigenotoxic evaluation showed that the non-delipidated extract (100 µg/mL) reduced methyl methanesulfonate-induced chromosomal damage in simultaneous and post-treatment conditions, while the delipidated extract was only effective for post-treatment. Conclusions: Aqueous extracts of B. cheilantha exhibit antioxidant and antigenotoxic properties. At active concentrations, they were non-cytotoxic and non-genotoxic. The non-delipidated extract, in particular, showed the strongest genome-protective potential, supporting its traditional use and highlighting its relevance in the development of natural therapeutic agents. Full article

This study aimed to investigate the chemical composition, antioxidant activity, and in vitro antidiabetic properties of extracts obtained from ripe, unripe, and fermented (unripe) cornelian cherry (Cornus mas L.) fruits. Polyphenols were identified using UPLC-ESI-qTOF-MS/MS and quantified by HPLC-PDA. Antioxidant activity was evaluated using ABTS, DPPH, and FRAP assays, while enzyme inhibitory activity was determined for α-glucosidase and α-amylase. Additionally, the effects of C. mas extracts on insulin sensitivity in adipocytes were investigated. The study’s results showed that each of the extracts tested contained varying proportions of substances with proven health-promoting properties. The extract from ripe fruits was characterized by the highest loganic acid content, whereas the extract from fermented unripe fruits contained a high amount of gallic acid, released through the hydrolysis of tannins during fermentation. The extract from unripe fruits exhibited the highest tannin content and the strongest antioxidant activity. All extracts inhibited α-glucosidase and α-amylase to a similar extent and improved insulin-stimulated glucose uptake in 3T3-L1 adipocytes without affecting INSR or SLC2A4 expression. In conclusion, extracts from unripe and fermented C. mas fruits may represent promising agents for alleviating insulin resistance and preventing type 2 diabetes. Full article

Beef production on chemically uniform grass monocultures can limit nutrient synchrony and contribute to uneven pasture use. We evaluated whether supplementing tannins with bioactive plant secondary compounds improves foraging dynamics and landscape use by beef cattle grazing a meadow bromegrass monoculture in ways aligned with rangeland sustainability. Twenty-four Angus cow–calf pairs were allocated to six 3.6-ha paddocks (four pairs/paddock), randomly assigned to Control (Ctrl; n = 3) or Tannin treatment (TT; n = 3). Animals received 1 kg/cow/day of DDGs, with TT receiving an added 0.4% tannins (2:1 condensed:hydrolyzable). Grazing occurred during four 15-day periods (July–September) across two years. Data were analyzed with mixed-effects models. Tannins did not alter biomass removal or cow weight loss (p > 0.05). However, TT cows exhibited longer evening grazing (2.9 vs. 2.1 h), fewer standing-to-lying transitions (5.7% vs. 7.3%), and more even spatial grazing distribution (CV = 1.861 vs. 2.13; p < 0.05), and greater water consumption (147 vs. 121 L/day; p < 0.01). Average daily gain of calves was numerically greater in TT compared to Ctrl (1.03 vs. 0.93 kg/day; p = 0.27). Collectively, these shifts promoted by tannins point to enhanced evening intake opportunities and reduced patch overuse, outcomes consistent with improved welfare and more uniform pasture utilization two pillars of sustainable grazing. Increased water demand under tannins highlights a management consideration for arid systems. Overall, moderate tannin inclusion was compatible with sustainable grazing by promoting even pasture use and potentially improving nutrient use efficiency without compromising intake. Full article

Tannin foams are polymeric, porous materials produced from plant tannins, with good thermal insulation and fire-retardant properties. Although research has mainly concentrated on usage of condensed tannins (CTs), interest in a second group, hydrolyzable tannins (HTs), is growing. This study evaluated the usability of glyoxal as a single crosslinker for condensed and hydrolyzable tannins in foams created through mechanical agitation, using various ratios of chestnut (HT) and quebracho (CT) tannins. Glyoxal could react with chestnut tannin, but foams with only chestnut collapsed before hardening due to its slow reactivity, with 70% chestnut as the maximum viable content. Increasing the chestnut tannin amount reduced the foamability and compression strength, resulting in higher density and increased pore size. At a similar density (~210 kg m⁻³), the 70%-HT foam reached only one-third the compressive strength of the pure CT foam (0.22 vs. 0.61 MPa), while the pure CT foam showed a smaller mean pore size (189 vs. 365 µm) despite its lower mean density (208 vs. 241 kg m⁻³). The fire resistance and thermal conductivity appeared unaffected by the tannin type and instead depended on the foam density, with thermal conductivities ranging from 56 to 71 mW/(m·K). Leaching tests showed a slight increase in leaching for formulations with higher chestnut tannin contents, with 15% to 24% of acid recovered after the leaching cycle. The ¹³C-NMR analysis revealed the glyoxal crosslinks at the free position of the A-ring in CTs and at the free ortho ones of the gallic/ellagic moieties in HTs. Overall, this study demonstrated that tannin foams can be produced using glyoxal as a single crosslinker, allowing for up to 70% substitution of the condensed tannin component in the formulation. Full article

This study investigated the year-round metabolomic variation in Fucus serratus (FS) and F. vesiculosus (FV) collected monthly from Danish coastal water around Aarhus Bay. Untargeted high-resolution liquid chromatography–mass spectrometry profiling (LC-HRMS), combined with multivariate data analysis and temporal clustering analysis, revealed that species identity was the primary driver of metabolic separation, followed by seasonal variation. FS showed higher levels of hydrolyzable tannins, flavonoid derivatives, aromatic amino acids, and glutamine-rich peptides, whereas FV was enriched in complex phlorotannins, tricarboxylic acid cycle intermediates, and carnitine derivatives. Temporal analysis identified recurring seasonal patterns across both species, including spring increases in amino acids, purine metabolites, and osmolytes; mid-summer peaks in mannitol and sulfated derivatives; and late-autumn elevations in phenolic compounds and betaine-type osmolytes. Despite apparent interspecific differences, several metabolite groups exhibited similar seasonal dynamics, suggesting shared physiological strategies associated with growth activation in spring, metabolic adjustment during summer to possible increased grazing pressure, and nutrient reallocation prior to winter. These findings provide a comprehensive, high-resolution view of seasonal metabolomic patterns in Fucus spp., offering new insights into their biochemical ecology and supporting the targeted utilization of these species for applications requiring specific metabolite profiles. Finally, this study contributes to the creation or expansion of metabolomic libraries for HRMS specific to Fucus seaweeds. Full article

This study examined the effects of alfalfa silage versus alfalfa hay in a total mixed ration (TMR) on milk yield, rumen fermentation, and nutrient digestibility in dairy cows. Hydrolyzed tannins (HT) were supplemented individually to assess changes. Thirty-two multiparous Holstein cows (DIM: 94 ± 8 d; milk yield: 41 ± 2 kg) were assigned to four treatments in a 2 × 2 factorial design: basal diet (alfalfa hay, H, or alfalfa silage, S) and additive (control, C, or 100 g/d HT, T). Production performance, rumen fermentation, nutrient digestibility, and blood metabolites were evaluated. Compared with group H, group S had a 0.16% higher milk protein percentage and significantly higher fat-corrected milk yield, milk fat percentage, fat-to-protein ratio, total solids, and milk urea nitrogen. After feeding, the ST group had increased ruminal pH. HT supplementation significantly decreased ruminal NH₃-N levels (p < 0.05) and increased microbial crude protein (MCP) content (p < 0.05). Group H showed no significant changes, and the effects of HT were less evident in hay-fed cows than in silage-fed cows. In summary, alfalfa silage feeding increased ruminal microbial populations, while HT supplementation mitigated the post-feeding decline in ruminal pH. Considering the relatively small sample size (n = 32), the results should be viewed as indicative rather than conclusive, and future studies with larger cohorts will be valuable to confirm and extend these findings. Full article

Tannases (tannin acyl hydrolases, EC 3.1.1.20) are enzymes of industrial interest due to their ability to hydrolyze hydrolyzable tannins into bioactive compounds like gallic acid. In this study fungal strains capable of producing extracellular tannase were isolated and identified. From tannin-rich substrates, 24 fungal isolates were obtained, of which 17 showed tannase activity. Molecular identification based on calmodulin gene sequencing identified three species of tannase-producing black aspergilli: Aspergillus luchuensis, A. niger (formerly A. welwitschiae), and A. uvarum. The isolate A. uvarum HT4 exhibited the highest extracellular tannase activity (182 U/mL) and was selected for further study. Whole-genome sequencing of HT4 revealed 15 putative tannase genes, most sharing high identity with A. uvarum CBS 121591. Two divergent genes appeared to be acquired via horizontal gene transfer from Aspergillus brunneoviolaceus and Penicillium angulare. Proteomic analysis of the secretome confirmed the expression of two extracellular tannases. The enzyme showed optimal activity at pH 5.0–6.0 and 40–50 °C. Secretome analysis revealed hydrolytic enzymes typical of saprophytic fungi in lignocellulose-rich environments. Importantly, no biosynthetic gene clusters of major mycotoxins were detected, supporting the biosafety of HT4 for industrial applications. Full article

Oxidative and inflammatory stresses contribute to the development of many intestinal pathologies. This study characterized the polyphenolic profile and biological activity of a hydroalcoholic extract obtained from the fruit pulp of Feijoa sellowiana on HT29 intestinal epithelial cells subjected to oxidative (H₂O₂) and inflammatory (cytokines) stress. HPLC-DAD-MS analysis revealed an interesting phenolic composition, rich in hydrolyzable tannins (HHDP-glucose, pedunculagin and other ellagic acid derivatives) and condensed tannins (procyanidin dimers), with a total polyphenol content of 8.07 mg/g GAE. The extract was non-cytotoxic up to 160 µg/mL and exerted a protective effect against the cytokine-induced reduction in cell viability. In vitro assays confirmed its strong antioxidant and scavenging capacity. The scratch assay suggested enhanced cell migration. The extract modulated the activity of key metabolic enzymes restoring glucose-6-phosphate dehydrogenase and enolase activity, while supporting glycolytic flux through pyruvate kinase and lactate dehydrogenase. PCA and Pearson correlation analyses confirmed a treatment-dependent modulation of the metabolic and redox profile, suggesting a regulatory role beyond a mere scavenging effect. These findings highlight the nutraceutical potential of feijoa polyphenols, not only as direct antioxidants but also as modulators of cellular metabolism and redox homeostasis, supporting their application in gastrointestinal disorders with oxidative or inflammatory components. Full article

Background/Objectives: Water and alcohol extracts of Epilobium have gained attention due to their high concentration of bioactive compounds and their associated health benefits. This review aimed to evaluate the effects of Epilobium parviflorum Schreb. (Onagraceae) preparations on vascular health in light of its medical applications in different human diseases over the last five years. Materials and Methods: A literature search was undertaken of databases such as PubMed/Medline, Scopus, and Google Scholar for original articles published between March 2000 and March 2025. The keywords used were “aortic rings”, “ellagitannins”, “Epilobium”, “hydrolyzable tannins”, “hypotension”, “oenothein B”, “Onagraceae”, “systolic blood pressure”, “vasorelaxation”, and “willow herb”. Results: The E. parviflorum Schreb. herb has been used as a remedy in folk medicine and has a variety of therapeutic properties. These include its preventive effects and ability to relieve symptoms in patients with benign prostate hyperplasia, prostatitis, and a variety of cancers. Other properties include effects on kidney and urinary tract diseases, lipid regulation, and skin infections. The herb also has antibacterial properties. E. parviflorum contains bioactive compounds such as oenothein B, quercetin-3-O-glucuronide, and myricetin-3-O-rhamnoside. At low doses, these compounds contribute to a reduction in oxidative stress due to their antioxidant and immunostimulatory effects, positively reducing inflammation, which can cause certain conditions. At higher concentrations, Epilobium generates reactive oxygen species that stimulate the body’s defense mechanisms against a variety of cancers. The presence of oenothein B in E. parviflorum may influence the production and storage of nitric oxide, which, in turn, promotes vasodilation and regulates blood pressure. Conclusions: Although the potential application of E. parviflorum in metabolic disorders has not been extensively studied before, its antioxidant and anti-inflammatory properties are well documented and suggest potential pathways for future research and the therapeutic development of preparations to benefit vascular health. Full article

This study investigated the effects of microenapsulated hydrolyzed tannins (MHTs) on the growth performance and meat quality of Zhongshan shelducks. A total of 288 healthy Zhongshan shelducks with an average initial weight of 1790.27 ± 0.14 kg were randomly divided into four groups through a 56 d experiment period and were fed a basal diet supplemented with 0 (CON), 400, 800, and 1600 mg/kg MHTs, respectively. Results showed that 400 and 800 mg/kg MHTs improved the final body weight, average daily gain, glutathione peroxidase activity, and total antioxidant capacity compared to CON (p ≤ 0.05). The diet supplemented with 400 mg/kg MHTs decreased shear force and 800 mg/kg MHTs increased the yield of pectoralis major muscle compared to CON (p ≤ 0.05). Dietary MHTs increased inosine monophosphate content and decreased percentage C14:0 content in meat; however, the b*45 min value, 48 h drip loss, and shear force were increased but the percentage intramuscular fat (IMF) content was decreased in pectoralis major muscle with the increase in MHTs (p ≤ 0.05). Compared to CON, 400 and 800 mg/kg MHTs increased the percentage content of IMF, C18:1n-9, C18:2n-6, monounsaturated fatty acids, polyunsaturated fatty acids, and unsaturated fatty acids in pectoralis major muscle (p ≤ 0.05). Furthermore, 400 and 800 mg/kg MHTs improved the lipid metabolism of IMF deposition, fatty acid uptake, and adipogenesis by activating the peroxisome proliferator-activated receptor gamma pathway to regulate fatty acid synthetase and lipoprotein lipase genes. In conclusion, diets supplemented with 400 and 800 mg/kg MHTs could improve growth, meat quality, antioxidant capacity, and lipid metabolism in Zhongshan shelducks. Full article

This study aimed to evaluate the effects of dietary supplementation with increasing levels of a polyherbal phytogenic additive (PPA) on growth performance, health parameters, and blood metabolites of dairy calves. Forty female Holstein calves (43.35 ± 2.41 kg body weight and 25.1 ± 2.2 d of age) were housed in individual pens and randomly assigned to four treatments (n = 10) with increasing levels of PPA: 0 (CON), 2 (PPA2), 3 (PPA3), and 4 (PPA4) g PPA/d for 67 d. Compared to the CON treatment, supplementation with the PPA2 treatment increased (quadratic effect p = 0.02) the average daily gain and final body weight of the dairy calves. Also, a higher starter intake (SI), and intake of milk + milk replacer was observed (linear and quadratic effect p = 0.0001) in response to supplementation with the PPA2, PPA3, and PPA4 treatments. The evaluated treatments did not affect (p > 0.05) the feed conversion ratio, or the number of cases of diarrhea, pneumonia, and otitis. The evaluated treatments did not affect (p > 0.05) most of the hematological and biochemical blood parameters. However, compared to the CON treatment, supplementation with the PPA2 treatment increased (quadratic effect p < 0.05) the blood concentration of the segmented neutrophils and plasma protein. Likewise, the serum glucose concentration decreased (linear effect p < 0.05) with supplementation of the PPA2, PPA3, and PPA4 treatments. Compared with the CON treatment, the PPA4 supplementation decreased the serum urea concentration (linear effect p = 0.04). In conclusion, supplementation with 2 g/d of PPA can be used as a natural alternative to improve the growth rate and stimulate starter and milk + milk replacer intake in dairy calves without adverse effects on health parameters or blood metabolites. Full article

Tannins, a diverse class of polyphenolic compounds, are widely present in a variety of plant-based foods and beverages, where they contribute significantly to flavor, astringency, and numerous health benefits. Known for their antioxidant, anti-inflammatory, and cardioprotective properties, tannins are associated with a reduced risk of chronic diseases such as cardiovascular disease, cancer, and diabetes. Their bioavailability and metabolism are influenced by factors such as polymerization, solubility, and interactions with the gut microbiota. Tannin-rich beverages, including tea, wine, fruit juices, and cider, offer a range of health-promoting effects, including antioxidant, cardioprotective, and antimicrobial activities. In addition, tannins contribute significantly to the sensory and nutritional characteristics of fruits, nuts, and vegetables, influencing flavor, color, and nutrient absorption. The levels and efficacy of tannins are subject to variation due to factors such as ripeness and food processing methods, which can increase their impact on food quality and health. This review provides a comprehensive examination of the bioactive roles of tannins, their nutritional implications, and their sensory effects, highlighting their importance in both dietary applications and overall well-being. Full article

This study compared the effect of phenolics extracted from four different types of pomegranate peels for controlling the growth of Salmonella enterica and enterohemorrhagic Escherichia coli. Cells of the two bacterial cultures (5 log CFU/mL) were treated in tryptic soy broth containing 0, 1, or 2% ethanolic extracts of four pomegranate peels for 5, 10, or 24 h at 25 °C. The surviving cells were recovered on a general-purpose agar and a selective medium. The extracts of three products were more effective (p ≤ 0.05) against E. coli than the extract of the remaining product, which had a similar activity to the extracts of two of the products used against S. enterica. Longer treatment time and higher extract concentration resulted in greater pathogen population reductions. The bacterial strains used had varied susceptibility to the extracts. Reductions in cell population positively correlated with the total contents of hydrolyzable tannins in the treatment systems. These findings suggested that ethanolic extracts of evaluated pomegranate peels had inhibitory activities against the two bacterial pathogens. This highlights the potential of pomegranate peels as a promising natural alternative to conventional antimicrobials for controlling foodborne pathogens like S. enterica and E. coli. Full article

Among 79 Bacillus spp. isolated from Miang, a fermented tea in north Thailand, 17 Bacillus strains were selected with probiotic potential in Nile tilapia culture based on the capabilities of bacteriocin production and associated antimicrobial activities against fish pathogens, Aeromonas hydrophila and Streptococcus agalactiae. However, only six isolates were selected for further extensive studies based on the strength of their antimicrobial activities and their tolerance against simulated gastrointestinal conditions. The molecular identification by 16S rRNA gene sequence analysis revealed that five isolates, K2.1, K6.1, K7.1, K15.4, and K22.6, were Bacillus tequilensis, and the isolate K29.2 was Bacillus siamensis. B. siamensis K29.2 showed complete susceptibility to antibiotics tested in this study, while B. tequilensis K 15.4 showed moderate resistance to some antibiotics; therefore, both strains were selected as potential probiotic bacteria. B. tequilensis K15.4 and B. siamensis K29.2 were capable of the production and secretion of extracellular protease and polysaccharide degrading enzymes, including cellulase, xylanase, and β-mannanase. The tannin tolerant test also demonstrated their ability to grow on selective agar plates and secrete cellulase and β-mannanase in the presence of hydrolyzable tannin. In addition, in vitro digestion of commercial fish substrate revealed that the extracellular enzymes produced by both strains efficiently reacted with feed protein and polysaccharides. Based on the results from this study, B. siamensis K29.2 was deemed to have the highest potential multifunctional probiotic qualities for application in Nile tilapia culture, while the antibiotic-resistant gene in B. tequilensis K15.4 must be clarified before field application. Full article