Polyphenol Extracts from Ziziphus jujuba Mill. "Junzao" Attenuates Ulcerative Colitis by Inhibiting the NLRP3 and MAPKs Signaling Pathways and Regulating Gut Microbiota Homeostasis in Mice.

SCOPE: Polyphenols are the major active substances in red jujube fruit, and their anti-inflammatory and antioxidant activities suggest their potential utility in the prevention of ulcerative colitis (UC). METHODS AND RESULTS: In this study, the effect of polyphenol extracts from red jujube (Ziziphus jujuba Mill. "Junzao") (PERJ) on the dextron sulfate sodium (DSS)-induced UC mice is investigated. The result shows that PERJ effectively improves clinical symptoms, including food and water intake, the disease activity insex (DAI) and spleen index, and routine blood levels, and alleviates the shortening of the colon, in mice with DSS-induced UC. Meanwhile, PERJ remarkably decreases the expression of proinflammatory factors. Moreover, PERJ repairs intestinal barrier damage by increasing the expression level of mucin 2 and mucin 3, and the result is also confirmed in the histological assessment. Besides, the expression levels of Nod-like receptor family pyrin domain-containing 3 (NLRP3) and mitogen-activated protein kinase cascade (MAPKs) signaling pathway-related proteins are inhibited by the PERJ administration. Finally, 16S rRNA sequencing analyses reveal that PERJ reverses intestinal microbiota dysbiosis by enhancing the abundance of Firmicutes and decreasing that of Proteobacteria and Bacteroidetes. CONCLUSION: PERJ probably inhibits the development of UC by suppressing the NLRP3 and MAPKs signaling pathways and regulating gut microbiota homeostasis, and can be considered as a potential resource for preventing UC.

Effects of Lignin-Diverted Reductant with Polyphenol Oxidases on Cellulose Degradation by Wild and Mutant Types of Lytic Polysaccharide Monooxygenase.

Establishing a multi-enzyme synergistic lignocellulosic biodegradation system using lytic polysaccharide monooxygenase (LPMO) and polyphenol oxidases is vital for efficiently utilizing plant biomass waste, ultimately benefiting the carbon cycle and promoting environmental protection. Single-residue mutations of LPMO can improve the efficiency of lignocellulosic biomass degradation. However, the activity of mutant-type LPMO in relation to lignin-diverted reducing agents has not been sufficiently explored. In this study, laccase and tyrosinase were initially investigated and their optimal conditions and impressive thermal stability were revealed, indicating their potential synergistic abilities with LPMO in lignocellulose biodegradation. When utilizing gallic acid as a reducing agent, the activities of LPMOs were increased by over 10%, which was particularly evident in mutant-type LPMOs after the addition of polyphenol oxidases. In particular, the combination of tyrosinase with either 4-hydroxy-3-methoxyphenylacetone or p-coumaric acid was shown to enhance the efficacy of LPMOs. Furthermore, the highest activity levels of wild-type LPMOs were observed with the addition of laccase and 3-methylcatechol. The similarities between wild and mutant LPMOs regarding their activities in lignin-diverted phenolic compounds and reducing agents are almost identical, suggesting that the single-residue mutation of LPMO does not have a detrimental effect on its performance. Above all, this study indicates that understanding the performance of both wild and mutant types of LPMOs in the presence of polyphenol oxidases and various reducing agents constitutes a key link in the industrialization of the multi-enzyme degradation of lignocellulose.

In vitro inhibition of α-Synuclein aggregation and disaggregation of preformed fibers by polyphenol hybrids with 2-conjugated benzothiazole.

The misfolding and aggregation of α-Syn play a pivotal role in connecting diverse pathological pathways in Parkinson's disease (PD). Preserving α-Syn proteostasis and functionality by inhibiting its aggregation or disaggregating existing aggregates using suitable inhibitors represents a promising strategy for PD prevention and treatment. In this study, a series of benzothiazole-polyphenol hybrids was designed and synthesized. Three identified compounds exhibited notable inhibitory activities against α-Syn aggregation in vitro, with IC50 values in the low micromolar range. These inhibitors demonstrated sustained inhibitory effects throughout the entire aggregation process, stabilizing α-Syn proteostasis conformation. Moreover, the compounds effectively disintegrated preformed α-Syn oligomers and fibers, potentially by binding to specific domains within the fibers, inducing fibril instability, collapse, and ultimately resulting in smaller-sized aggregates and monomers. These findings offer valuable insights into the therapeutic potential of polyphenol hybrids with 2-conjugated benzothiazole targeting α-Syn aggregation in the treatment of PD.

Fe3+-induced coordination cross-linking gallic acid-carboxymethyl cellulose self-healing hydrogel.

Self-healing hydrogel is a promising soft material for applications in wound dressings, drug delivery, tissue engineering, biomimetic electronic skin, and wearable electronic devices. However, it is a challenge to fabricate the self-healing hydrogels without external stimuli. Inspired by mussel, the metal-catechol complexes were introduced into the hydrogel systems to prepare the mussel-inspired hydrogels by regulating the gelation kinetics of Fe3+ crosslinkers with gallic acid (GA) in this research. The amine-functionalized carboxymethyl cellulose (CMC) was grafted with GA and then chelated with Fe3+ to form a multi-response system. The crosslinking of carboxymethyl cellulose-ethylenediamine-gallic acid (CEG) hydrogel was controlled by adjusting the pH to affect the iron coordination chemistry, which could enhance the self-healing properties and mechanical strength of hydrogels. In addition, the CEG hydrogel exhibited great antibacterial and antioxidant properties. And the CEG hydrogel could strongly adhere to the skin tissue. The adhesion strength of CEG hydrogel on pigskin was 11.44 kPa, which is higher than that of commercial wound dressings (∼5 kPa). Moreover, the thixotropy of the CEG hydrogel was confirmed with rheological test. In summary, it has great potential in the application field of wound dressing.

New plant polyphenol-derived tannic acid-based chromium-free tanning agent for sustainable and clean leather production.

This study aimed to prepare a new bio-based chromium-free tanning agent. The green epoxide monocase ethylene glycol diglycidyl ether (EGDE) was grafted with tannic acid (TA) derived from natural plant using the one-pot method to synthesize new plant polyphenol-derived tannic acid-based chromium-free tanning agents (TA-EGDE) with abundant terminal epoxides. FTIR, 1H NMR, XPS, GPC, SEM, and other analytical techniques were used to characterize tanning agents. These consequences manifested that EGDE was successfully grafted with the phenol hydroxyl group of TA. The epoxide value of TA-EGDE showed a tendency to increase and then decrease with increasing EGDE dosage, and the epoxide value of TA-EGDE-2 attained a maximum of 0.262 mol/100 g. GPC analysis showed that the formula weight of the prepared TA-EGDE was partially distributed above 5000 Da. The tanning experiment demonstrated that the shrinkage temperatures (Ts) of the TA-EGDE-tanned leathers were all higher than 81.5 °C. Compared with the traditional commercial chromium-free tanning agent (F-90, TWS), TA-EGDE-tanned leathers exhibited higher Ts and better mechanical properties. The TA-EGDE prepared in this study not only has ecological environmental protection but also provides finished leather with good moisture, heat resistance, and mechanical properties.

Dietary Polyphenols: What is the Estimated Intake in Population Studies With Adults and Elderly People?

Estimates of dietary intake of polyphenols have been limited to specific samples from certain population groups, and different databases have been used to quantify the levels of these compounds, which makes it difficult to compare results. PURPOSE OF REVIEW: This review collated estimates of polyphenol intake from population studies including adults and elderly from different parts of the world by using a single database: Phenol-Explorer. RECENT FINDINGS: Through seven population-based studies performed in five different countries, it was possible to identify that Brazil was the country with the lowest intake of polyphenols, whereas Poland had the highest dietary intake. The most ingested subclasses of polyphenols in different countries were phenolic acids and flavonoids, and non-alcoholic beverages (coffee, tea, and orange juice) were the foods that most contributed to the intake of polyphenols. Despite the attempt to standardize this study to obtain worldwide intake estimates that could be comparable, gaps were found regarding the assessment of food consumption, standardization to obtain the polyphenol content of foods in Phenol-Explorer, calculation in aglycone equivalents, and caloric adjustment of the estimates. There is a need for more studies on the dietary polyphenols intake of representative samples of populations from different countries to collate more data on the quantities consumed and the main contributing foods.

Protective effects of sugarcane polyphenol against UV-B-induced photoaging in Balb/c mouse skin: Antioxidant, anti-inflammatory, and anti-glycosylation Effects.

Although the benefits of sugarcane polyphenol (SP) are well documented, its function in preventing photoaging has not yet been investigated. This study aimed to investigate the protective effects of SP in preventing ultraviolet (UV)-B-induced skin photoaging in Balb/c mice, as well as the underlying mechanism. Chlorogenic acid was determined to be the primary component of SP by using high-performance liquid chromatography-mass spectrometry. SP and chlorogenic acid were orally administrated to mice for 56 days, and UV-B radiation exposure was administered 14 days after SP and chlorogenic acid administration and lasted 42 days to cause photoaging. SP and chlorogenic acid administrations significantly alleviated the UV-B-induced mouse skin photoaging, as indicated by the decrease in epidermal thickness, increase in the collagen (COL) volume fraction, and elevation in type 1 and type 3 COL contents. Notably, both SP and chlorogenic acid effectively reversed the overexpression of matrix metalloproteinase induced by UV-B exposure in the mouse skin. Furthermore, SP and chlorogenic acid reduced the expression of receptor for advanced glycosylation end products in the mice; amplified the activities of antioxidant enzymes superoxide dismutase and catalase; reduced malondialdehyde levels; and decreased inflammatory cytokines interleukin 1ß, interleukin 6, and tumor necrosis factor α levels. SP could be a prospective dietary supplement for anti-photoaging applications due to its antioxidant, anti-inflammatory, and anti-glycosylation attributes, and chlorogenic acid might play a major role in these effects. PRACTICAL APPLICATION: This study can provide a scientific basis for the practical application of sugarcane polyphenols. We expect that sugarcane polyphenols can be used in food and beverage products to provide flavor while combating skin aging.

The enhanced affinity of moderately hydrolyzed whey protein to EGCG promotes the isoelectric separation and unlocks the protective effects on polyphenols.

The instability and discoloration of (-)-epigallocatechin-3-gallate (EGCG) constrain its application in functional dairy products. Concurrently, challenges persist in the separation and utilization of whey in the dairy industry. By harnessing the interactions between polyphenols and whey proteins or their hydrolysates, this study proposed a method that involved limited enzymatic hydrolysis followed by the addition of EGCG and pH adjustment around the isoelectric point to obtain whey protein hydrolysates (WPH)-EGCG. Over 92 % of protein-EGCG complexes recovered from whey while ensuring the preservation of α-lactalbumin. The combination between EGCG and WPH depended on hydrogen bonding and hydrophobic interactions, significantly enhanced the thermal stability and storage stability of EGCG. Besides, the intestinal phase retention rate of EGCG in WPH-EGCG complex was significantly increased by 23.67 % compared to free EGCG. This work represents an exploratory endeavor in the improvement of EGCG stability and expanding the utilization approaches of whey.

An overview on the cellular mechanisms of anthocyanins in maintaining intestinal integrity and function.

Structural and functional changes of the intestinal barrier, as a consequence of a number of (epi)genetic and environmental causes, have a main role in penetrations of pathogens and toxic agents, and lead to the development of inflammation-related pathological conditions, not only at the level of the GI tract but also in other extra-digestive tissues and organs. Anthocyanins (ACNs), a subclass of polyphenols belonging to the flavonoid group, are well known for their health-promoting properties and are widely distributed in the human diet. There is large evidence about the correlation between the human intake of ACN-rich products and a reduction of intestinal inflammation and dysfunction. Our review describes the more recent advances in the knowledge of cellular and molecular mechanisms through which ACNs can modulate the main mechanisms involved in intestinal dysfunction and inflammation, in particular the inhibition of the NF-κB, JNK, MAPK, STAT3, and TLR4 proinflammatory pathways, the upregulation of the Nrf2 transcription factor and the expression of tight junction proteins and mucins.

In vitro Immunostimulant Activity of the Polyphenolic Extract from the Arctic Brown Algae Fucus vesiculosus.

Polyphenols (PP) found in brown algae are known for their wide range of biological activities including noteworthy antitumor properties. This article presents a method for obtaining an active polyphenolic extract from the Arctic alga Fucus vesiculosus with 98% purity and radical scavenging activity equivalent to 862 mg of ascorbic acid per gram of extract. Immunostimulant effects of polyphenols were assessed in vitro using venous blood from two groups of people: healthy people (HP) and people with chronic undifferentiated lymphocytic leukemia (LP). Polyphenols activated the surface properties of immunocompetent cells. Specifically, polyphenols dose-dependently increased the percentage of cells' spreading and adhesion by 2-3 times. Additionally, polyphenols increased the number of activated lymphocytes in the LP blood to levels characteristic of HP. Given their natural origin, high activity, non-toxicity, and straightforward production process, these studied polyphenols exhibit immense potential for use as new pharmaceuticals or as active components with immunostimulatory effects.

Research progress on the functions and biosynthesis of theaflavins.

Theaflavins are beneficial to human health due to various bioactivities. Biosynthesis of theaflavins using polyphenol oxidase (PPO) is advantageous due to cost effectiveness and environmental friendliness. In this review, studies on the mechanism of theaflavins formation, the procedures to screen and prepare PPOs, optimization of reaction systems and immobilization of PPOs were described. The challenges associated with the mass biosynthesis of theaflavins, such as poor enzyme activity, undesirable subproducts and inclusion bodies of recombinant PPOs were presented. Further strategies to solve these challenges and improve theaflavins production, including enzyme engineering, immobilization enzyme technology, water-immiscible solvent-water biphasic systems and recombinant enzyme technology, were proposed.

Identification of phenolic compounds from fermented Moringa oleifera Lam. leaf supplemented with Fuzhuan brick tea and their volatile composition and anti-obesity activity.

As a nutritious plant with valuable potential, the Moringa oleifera Lam. (MOL) leaf addition on Fuzhuan brick tea (FBT) for the co-fermentation (MOL-FBT) was an industry innovation and a new route to make full use of MOL leaf. After optimization of the extraction conditions, the best conditions for the polyphenols extraction method from MOL-FBT (MFP) were 60°C for 40 min (1:80, V/W) using response surface methodology. A total of 30 phenolics were identified and quantified. Most of the polyphenols were increased after adding MOL leaf for co-fermentation compared to FBT polyphenols. In particular, caffeic acids were found only in MFP. Moreover, the MFP received high value in taste, aroma, and color. In total, 62 volatile flavor compounds, consisting of 3 acids, 5 alcohols, 15 aldehydes, 4 esters, 20 hydrocarbons, 10 ketones, and 5 others, were identified in MFP. In addition, MFP inhibited 3T3-L1 preadipocyte differentiation in a dose-dependent manner and decreased lipid accumulation via the peroxisome proliferator-activated receptor gamma (PPARγ)/CCAAT/enhancer binding protein alpha (CEBPα)/cluster of differentiation 36 (CD36) axis and induced a brown adipocyte-like phenotype. In vivo experiments were further conducted to confirm the in vitro results. MFP regulated lipid accumulation, glucose/insulin tolerance, improved liver and kidney function, and inhibited the secretion of pro-inflammatory factors by the PPARγ/CEBPα/CD36 axis and alleviated inflammation in high fat and high fructose diet-induced obese mice. In summary, MFP possesses high-quality properties and anti-obesity effects, as well as the great potential to be used as a novel functional food product.

Curcumin Effects on Age-Related Changes in Oral Immunity: An In Vivo Study.

The current study aimed to investigate the effects of ageing on oral immunity using ß-defensin (DEFB) 1/2 as a marker and evaluate the effects of curcumin (CUR) on these processes. The study sample included 30 male C57BL/6J mice divided into three groups based on the treatment method used. The young control (YC) and old control (OC) groups received 0.5% methylcellulose-400 (curcumin vehicle) orally for five days, whereas the CUR group of older mice received a curcumin solution suspended in 0.5% methylcellulose-400 (dose: 3.0 mg/kg body). DEFB1/2 and immune indicator levels were measured in the saliva and salivary glands posttreatment. The saliva volume and protein content were significantly reduced in the OC group compared to the YC group. CUR administration restored these parameters, decreased DEFB1 expression in the salivary gland and increased DEFB1/2 secretion and DEFB2 expression. These findings were supported by epigenetic gene regulation and partial cytokine activation from changes in WD40 repeat protein 5, Tumour Necrosis Factor alpha and interleukin-1beta. Curcumin can partially restore age-related changes in oral immune responses and promote oral health, thereby preventing frailty in the older population through a nutritional therapeutic pathway.

Effect of Addition of Tannin Extract from Underutilized Resources on Allergenic Proteins, Color and Textural Properties of Egg White Gels.

Tannins, present in numerous plants, exhibit a binding affinity for proteins. In this study, we aimed to exploit this property to reduce the concentration of allergenic egg white proteins. Tannins were extracted, using hot water, from the lyophilized powder of underutilized resources, such as chestnut inner skin (CIS), young persimmon fruit (YPF), and bayberry leaves (BBLs). These extracts were then incorporated into an egg white solution (EWS) to generate an egg white gel (EWG). Allergen reduction efficacy was assessed using electrophoresis and ELISA. Our findings revealed a substantial reduction in allergenic proteins across all EWGs containing a 50% tannin extract. Notably, CIS and BBL exhibited exceptional efficacy in reducing low allergen levels. The addition of tannin extract resulted in an increase in the total polyphenol content of the EWG, with the order of effectiveness being CIS > YPF > BBL. Minimal color alteration was observed in the BBL-infused EWG compared to the other sources. Additionally, the introduction of tannin extract heightened the hardness stress, with BBL demonstrating the most significant effect, followed by CIS and YPF. In conclusion, incorporating tannin extract during EWG preparation was found to decrease the concentration of allergenic proteins while enhancing antioxidant properties and hardness stress, with BBL being particularly effective in preventing color changes in EWG.

Tea (Camellia sinensis) cultivated in three agro-ecological regions of Bangladesh: Unveiling the variability of methylxanthine, bioactive phenolic compound, and antioxidant activity.

Tea (Camellia sinensis) is a widely consumed beverage known for its numerous health benefits, largely attributed to its rich content of quality determining secondary metabolites such as methylxanthine compounds and bioactive phenolic compounds. The goal of this study was to find out variations of the levels of methylxanthines, bioactive phenolic compounds, and antioxidant activity in methanolic and hot water extracts of 129 tea samples grown in three different ecological regions of Bangladesh named Panchagar, Sylhet, and Chattogram. Methylxanthine and bioactive phenolic compounds were determined by using HPLC-DAD, and the antioxidant profile was analysed by UV-vis spectrophotometric methods for methanol and hot water extracts of tea leaves. The IC50 values showed the trend as Panchagar > Sylhet > Chattogram and Sylhet > Chattogram > Panchagar for water and methanol extract, respectively. The results revealed significant (p < 0.05) variations in the levels of methylxanthines content: Panchagar > Chattogram > Sylhet. Caffeine was significantly higher (103.02 ± 5.55 mg/g of dry extract) in the methanolic extract of tea leaves of Panchagar district and lower (53.33 ± 4.30 mg/g of dry extract) in the hot water extract of Sylhet district. Panchagar and Chattogram possessed significantly (p < 0.05) higher catechin content for methanol (57.01 ± 5.50 mg/g dry extract) and hot water (55.23 ± 4.11 mg/g dry extract) extracts, respectively. The utilization of canonical discriminant functions yielded highly favorable outcomes in the classification of tea from three distinct cultivation origins in Bangladesh, relying on their inherent features. This study demonstrated the potential effects of geographical variations on the bioactive compounds and antioxidant properties of tea, emphasizing the importance of regional differences in tea cultivation for optimizing its health benefits as well as dispersing tea cultivation across the country.

Exploring the multimodal health-promoting properties of resveratrol: A comprehensive review.

Resveratrol, a natural polyphenol in various plants, has gained significant attention for its potential health-promoting properties. It has been demonstrated, after reviewing various clinical and in vitro studies, that resveratrol possesses potent antioxidant potential. Resveratrol demonstrates cellular component protection by directly neutralizing free radicals (FRs) and enhancing the expression of natural antioxidant enzymes, thereby mitigating oxidative damage to proteins, lipids, and nucleic acids. Clinical trials have shown promising results, indicating that resveratrol supplementation can enhance antioxidant defenses and reduce oxidative damage markers in various populations. In addition to its antioxidant effects, resveratrol exhibits potent anti-inflammatory properties. It can modulate key inflammatory pathways, such as nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs), thereby suppressing the production of pro-inflammatory cytokines and chemokines. Furthermore, resveratrol's multimodal effects extend beyond its antioxidant and anti-inflammatory properties. It has been discovered to exert regulatory effects on various cellular processes, including apoptosis, cell cycle progression, angiogenesis, and immunological responses. The primary aim of this review paper is to provide a thorough overview of the current knowledge on resveratrol, including its chemical composition, bioaccessibility, clinical effectiveness, and utilization in nanotechnology to enhance its bioavailability. From future perspectives, revising the administration methods for certain contexts and understanding the underlying systems responsible for resveratrol's effects will require further inquiry. For the highest potential health results, advanced trial-based research is necessary for combinational nano-delivery of resveratrol.

Pt/NiFe-LDH hybrids for quantification and qualification of polyphenols.

Polyphenols with antioxidant properties are of significant interest in medical and pharmaceutical applications. Given the diverse range of activities of polyphenols in vivo, accurate detection of these compounds plays a crucial role in nutritional surveillance and pharmaceutical development. Yet, the efficient quantitation of polyphenol contents and qualification of monomer compositions present a notable challenge when studying polyphenol bioavailability. In this study, platinum-modified nickel-iron layered double hydroxide (Pt/NiFe-LDH hybrids) were designed to mimic peroxidases for colorimetric analysis and act as enhanced matrices for laser desorption/ionization mass spectrometry (LDI MS) to quantify and qualify polyphenols. The hybrids exhibited an enzymatic activity of 33.472 U/mg for colorimetric assays, facilitating the rapid and direct quantitation of total tea polyphenols within approximately 1 min. Additionally, the heterogeneous structure and exposed hydroxyl groups on the hybrid surface contributed to photoelectric enhancement and in-situ enrichment of polyphenols in LDI MS. This study introduces an innovative approach to detect polyphenols using advanced materials, potentially inspiring the future development and applications of other photoactive nanomaterials.

Self-assembly of metal-polyphenolic network on biomass for enhanced organic contaminant capturing from water with a high cost-to-benefit ratio.

Nanomaterials present a vast potential as functional materials in environmental engineering. However, there are challenges with nanocomplex for recyclability, reliable/stable, and scale-up industrial integration. Here, a versatile, low-cost, stable and recycled easily metal-polyphenolic-based material carried by wood powder (bioCar-MPNs) adsorption platform was nano-engineered by a simple, fast self-assembly strategy, in which wood powder is an excellent substrate serving as a scaffold and stabilizer to prevent the nanocomplex from aggregating and is easier to recycle. Life cycle analysis highlights a green preparation process and environmental sustainability for bioCar-MPNs. The metal-polyphenolic nanocomplex coated on the wood surface in bioCar-MPNs presents a remarkable surface adsorption property (1829.4 mg/g) at a low cost (2.4 US dollars per 1000 g bioCar-MPNs) for organic dye. Quartz crystal microbalance analysis (QCM) demonstrates an existing strong affinity between polyphenols and organic dyes. Furthermore, Independent Gradient Model (IGM) and Hirshfeld surface analysis reveal the presence of the electrostatic interactions, π-π interactions, and hydrogen bonding. Meanwhile, adsorption efficiency of bioCar-MPNs maintains over 95% in the presence of co-existing ions (Na+, 0.5 M). Importantly, the reasonable utilization of biomass for water treatment can contribute to achieving the high-value and resource utilization of biomass materials.

Recent progress in promoting the bioavailability of polyphenols in plant-based foods.

Polyphenols are important constituents of plant-based foods, exhibiting a range of beneficial effects. However, many phenolic compounds have low bioavailability because of their low water solubility, chemical instability, food matrix effects, and interactions with other nutrients. This article reviews various methods of improving the bioavailability of polyphenols in plant-based foods, including fermentation, natural deep eutectic solvents, encapsulation technologies, co-crystallization and amorphous solid dispersion systems, and exosome complexes. Several innovative technologies have recently been deployed to improve the bioavailability of phenolic compounds. These technologies may be utilized to increase the healthiness of plant-based foods. Further research is required to better understand the mechanisms of action of these novel approaches and their potential to be used in food production.

Astringency and its sub-qualities: A review of astringency mechanisms and methods for measuring saliva lubrication.

Astringency is an important mouthfeel attribute that influences the sensory experiences of many food and beverage products. While salivary lubricity loss and increased oral friction were previously believed to be the only astringency mechanisms, recent research has demonstrated that non-tactile oral receptors can trigger astringency by responding to astringents without mechanical stimulation. Various human factors have also been identified that affect individual responses to astringents. This article presents a critical review of the key research milestones contributing to the current understanding of astringency mechanisms and the instrumental approaches used to quantify perceived astringency intensity. Although various chemical assays or physical measures mimic in-mouth processes involved in astringent mouthfeel, this review highlights how one chemical or physical approach can only provide a single measure of astringency determined by a specific mechanism. Subsequently, using a single measurement to predict astringency perception is overly idealistic. Astringency has not been quantified beyond the loss of saliva lubrication; therefore, non-tactile receptor-based responses must also be explored. An important question remains about whether astringency is a single perception or involves distinct sub-qualities such as pucker, drying, and roughness. Although these sub-quality lexicons have been frequently cited, most studies currently view astringency as a single perception rather than dividing it into sub-qualities and investigating the potentially independent mechanisms of each. Addressing these knowledge gaps should be an important priority for future research.