The reciprocal interaction between polyphenols and other dietary compounds: Impact on bioavailability, antioxidant capacity and other physico-chemical and nutritional parameters

Absolute kinetics of peroxidation and antioxidant protection of intact triglyceride vegetable oils

To verfy their difference from isolated fatty acids, the absolute kinetics of peroxidation was studied for seven triglyceride-based oils of olive (OLI-1, OLI-2), high-oleic sunflower (SUN-HO), high-oleic and high-linoleic safflower (SAF-HO, SAF-HL) grapeseed (GRA) and borage (BOR), by oxygen uptake monitoring, using 2,6-di-tert-butyl-4-methoxyphenol and 2,2,5,7,8-pentamethyl-6-chromanol as reference inhibitors. Propagation constants (kp/M-1 s-1 at 303 K in PhCl) were respectively 34.8 ± 2.3, 35.1 ± 1.8, 40.6 ± 5.5, 36.0 ± 7.7, 160.8 ± 5.1, 145.1 ± 24.5, 275.1 ± 63.8, while oxidizability responded to empirical equation kp(2kt)-½/M-½s-½ = 1.63 × 10-3[allyl >CH2/M] + 1.82 × 10-2[bisallyl >CH2/M], based on fatty acids residues assessed by GC-MS. Peroxidation kinetics was markedly different from that of isolated fatty acids. The H-bond basicity of all oils was measured by FT-IR affording Abraham's βH2 values in the range 0.55 ± 0.03. H-bonding explained the protection of oils measured for seven reference phenolic antioxidants, except for the catechols quercetin and caffeic acid phenethyl ester, which were 2-to-4-folds more effective than expected, supporting a proposed different mechanism.

Effects of the dose of administration, co-antioxidants, food matrix, and digestion-related factors on the in vitro bioaccessibility of rosmarinic acid - A model study

This study aimed to determine the effect of the administration dose, combinations with co-antioxidants (vitamin C, caffeic acid, chlorogenic acid, catechin, rutin), and different food matrices (cooked and lyophilized hen eggs, chicken breast, soybean seeds, potatoes) on the potential bioaccessibility of rosmarinic acid (RA) in simulated digestion conditions, depending on the digestion stage (gastric and intestinal) and the contribution of physicochemical and biochemical digestion factors. The in vitro bioaccessibility of RA depended on the digestion stage and conditions. The physicochemical factors were mainly responsible for the bioaccessibility of RA applied alone. The higher RA doses improved its bioaccessibility, especially at the intestinal stage of digestion. Furthermore, the addition of vitamin C and protein-rich food matrices resulted in enhanced intestinal bioaccessibility of RA. In the future, the knowledge of factors influencing the bioaccessibility of RA can help enhance its favorable biological effects and therapeutic potential.

Role of the gut-muscle axis in mitochondrial function of ageing muscle under different exercise modes

The fundamental role of the gut microbiota through the gut-muscle axis in skeletal muscle ageing is increasingly recognised. Metabolites derived from the intestinal microbiota are essential in maintaining skeletal muscle function and metabolism. The energy produced by mitochondria and moderate levels of reactive oxygen species can contribute to this process. Metabolites can effectively target the mitochondria, slowing the progression of muscle ageing and potentially representing a marker of ageing-related skeletal muscle loss. Moreover, mitochondria can contribute to the immune response, gut microbiota biodiversity, and maintenance of the intestinal barrier function. However, the causal relationship between mitochondrial function and gut microbiota crosstalk remains poorly understood. In addition to elucidating the regulatory pathways of the gut-muscle axis during the ageing process, we focused on the potential role of the "exercise-gut-muscle axis", which represents a pathway under stimulation from different exercise modes to induce mitochondrial adaptations, skeletal muscle metabolism and maintain intestinal barrier function and biodiversity stability. Meanwhile, different exercise modes can induce mitochondrial adaptations and skeletal muscle metabolism and maintain intestinal barrier function and biodiversity. Resistance exercise may promote mitochondrial adaptation, increase the cross-sectional area of skeletal muscle and muscle hypertrophy, and promote muscle fibre and motor unit recruitment. Whereas endurance exercise promotes mitochondrial biogenesis, aerobic capacity, and energy utilisation, activating oxidative metabolism-related pathways to improve skeletal muscle metabolism and function. This review describes the effects of different exercise modes through the gut-muscle axis and how they act through mitochondria in ageing to define the current state of the field and issues requiring resolution.

Se site targeted-two circles antioxidant in GPx4-like catalytic peroxide degradation by polyphenols (-)-epigallocatechin gallate and genistein using SERS

A Se site targeted-two circles antioxidant of polyphenols EGCG and genistein in glutathione peroxidase 4 (GPx4)-like catalytic peroxide H2O2 and cumene hydroperoxide degradation was demonstrated by surface-enhanced Raman scattering (SERS). Se atom's active center is presenting a 'low-oxidation' and a 'high-oxidation' catalytic cycle. The former is oxidized to selenenic acid (SeO-) with a Raman bond at 619/ 610 cm-1 assigned to the νO - Se by the hydroperoxide substrate at 544/ 551 cm-1 assigned to ωHSeC decreased. Under oxidative stress, the enzyme shifted to 'high-oxidation' catalytic cycle, in which GPx4 shuttles between R-SeO- and R-SeOO- with a Raman intensity of bond at 840/ 860 cm-1 assigned to νO[bond, double bond]Se. EGCG could act as a reducing agent both in H2O2 and Cu-OOH degradation, while, genistein can only reduce Cu-OOH, because it binds more readily to the selenium site in GPx4 than EGCG with a closer proximity, therefore may affect its simultaneous binding to coenzymes.

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.

Bioaccessibility of Rosmarinic Acid and Basil (Ocimum basilicum L.) Co-Compounds in a Simulated Digestion Model-The Influence of the Endogenous Plant Matrix, Dose of Administration and Physicochemical and Biochemical Digestion Environment

The objective of this study is to determine the effect of endogenous plant matrix components, dose and digestion-related factors on the bioaccessibility of rosmarinic acid and basil co-compounds in in vitro digestion conditions. Different forms of administration, i.e., basil raw plant material, dry extract, and isolated rosmarinic acid at various doses, were applied for the digestion experiment. To evaluate the contribution of biochemical and physicochemical digestion factors, samples were subjected to a full digestion process or treated only with a digestion fluid electrolyte composition without using biochemical components (i.e., digestion enzymes and bile salts), and bioaccessibility was monitored at the gastric and intestinal steps of digestion. The results showed that the components of the endogenous raw plant matrix significantly limited the bioaccessibility of rosmarinic acid and basil co-compounds, especially at the gastric stage of digestion. Physicochemical digestion factors were mainly responsible for the bioaccessibility of basil phytochemicals. Higher doses allowed maintenance of bioaccessibility at a relatively similar level, whereas the most negative changes in bioaccessibility were induced by the lowest doses. In conclusion, the determination of the bioaccessibility of bioactive phytochemicals from basil and factors influencing bioaccessibility may help in better prediction of the pro-health potential of this plant.

Study on the Digestive Behavior of Chlorogenic Acid in Biomimetic Dietary Fiber and the Antioxidative Synergistic Effect of Polysaccharides and Chlorogenic Acid

Chlorogenic acid (CA) is often combined with dietary fiber polysaccharides in plant foods, which may affect its digestive behavior and antioxidant activity. This study constructed a biomimetic dietary fiber (BDF) model by combining bacterial cellulose (BC) and pectin with CA and investigated the digestive behavior of CA in BDF. Additionally, the study examined the interaction and synergistic effects of polysaccharides and CA against oxidation. Results showed that BDF and natural dietary fiber had similar microstructures, group properties, and crystallization properties, and polysaccharides in BDF were bound to CA. After simulated gastrointestinal digestion, 41.03% of the CA existed in a conjugated form, and it was possibly influenced by the interaction between polysaccharides and CA. And the release of CA during simulated digestion potentially involved four mechanisms, including the disintegration of polysaccharide-CA complex, the dissolution of pectin, escape from BC-pectin (BCP) network structure, and diffusion release. And polysaccharides and CA may be combined through noncovalent interactions such as hydrogen bonding, van der Waals force, or electrostatic interaction force. Meanwhile, polysaccharides-CA combination had a synergistic antioxidant effect by the results of free-radical scavenging experiments, it was probably related to the interaction between polysaccharides and CA. The completion of this work has a positive significance for the development of dietary intervention strategies for oxidative damage.

Deeply analyzing dynamic fermentation of highland barley vinegar: Main physicochemical factors, key flavors, and dominate microorganisms

Highland barley vinegar, as a solid-state fermentation-type vinegar emerged recently, is well-known in Qinghai-Tibet plateau area of China. This work aimed to explore the main physicochemical factors, key flavor volatile compounds, and dominate microorganisms of highland barley vinegar during fermentation. The results showed that the decrease trend of reducing sugar, pH and the increase trend of amino acid nitrogen were associated with the metabolism of dominate bacteria, especially Lactobacillus and Acetobacter. Totally, 35 volatile compounds mainly including 20 esters, 10 alcohols, 2 aldehydes, 1 ketone and 2 pyrazines and 7 organic acids were identified. Especially, isoamyl acetate, acetyl methyl carbinol, ethyl caprylate, 1,2-propanediol, 3-methyl-1-butanol and ethyl isovalerate with high odor activity values were confirmed as key aroma compounds. Meanwhile, the relative average abundance of bacteria at genus level decreased significantly as fermentation time goes on. Among these microbes, Lactobacillus were the dominate bacteria at alcohol fermentation stage, Lactobacillus and Acetobacter were dominate at acetic acid fermentation stage. Furthermore, the correlations between dominate bacteria and the key volatile compounds were revealed, which highlighted Lactobacillus and Acetobacter were significantly correlated with key volatile compounds (|r| > 0.5, P < 0.01). The fundings of this study provide insights into the flavor and assist to improve the production quality of highland barley vinegar.

The amount of antioxidants in honey has a strong relationship with the plants selected by honey bees

As one of the main sources of natural antioxidants, flowering plants play a role in the prevention and treatment of many diseases directly and indirectly. Honey is considered as an important nutrient in the supply of natural antioxidants, the amount of which is directly dependent on the plant origin and geographical location of the bee feeding place. The existence of valuable communities of native and endemic plant species has turned Alborz, Zagros and Azerbaijan into the most important hubs of honey production in Iran. In this study, we collected samples of honey from more than 90 regions in Alborz, Zagros and Azerbaijan during the years 2020 to 2021. We evaluated the samples using melissopalynology method and measuring the amount of antioxidant activity. The rise of antioxidant activity in honey is dependent on the abundance of some plant families as well botanical origins. The abundance of plant families Rosaceae, Amaranthaceae, Fabaceae and Asteraceae showed a higher influence on the amount of antioxidants in honey than other plant families. Also, the abundance of plant families Rosaceae and Fabaceae increased with increasing altitude. In general, the amount of antioxidant activity of honey samples shows a different percentage under the influence of ecological and geographical changes.

Chronic Stress as a Risk Factor for Type 2 Diabetes: Endocrine, Metabolic, and Immune Implications

BACKGROUND

Chronic stress is a condition of pressure on the brain and whole body, which in the long term may lead to a frank disease status, even including type 2 diabetes (T2D). Stress activates the hypothalamus-pituitary-adrenal axis with release of glucocorticoids (GCs) and catecholamines, as well as activation of the inflammatory pathway of the immune system, which alters glucose and lipid metabolism, ultimately leading to beta-cell destruction, insulin resistance and T2D onset. Alteration of the glucose and lipid metabolism accounts for insulin resistance and T2D outcome. Furthermore, stress-related subversion of the intestinal microbiota leads to an imbalance of the gut-brain-immune axis, as evidenced by the stress-related depression often associated with T2D. A condition of generalized inflammation and subversion of the intestinal microbiota represents another facet of stress-induced disease. In fact, chronic stress acts on the gut-brain axis with multiorgan consequences, as evidenced by the association between depression and T2D. Oxidative stress with the production of reactive oxygen species and cytokine-mediated inflammation represents the main hallmarks of chronic stress. ROS production and pro-inflammatory cytokines represent the main hallmarks of stress-related disorders, and therefore, the use of natural antioxidant and anti-inflammatory substances (nutraceuticals) may offer an alternative therapeutic approach to combat stress-related T2D. Single or combined administration of nutraceuticals would be very beneficial in targeting the neuro-endocrine-immune axis, thus, regulating major pathways involved in T2D onset. However, more clinical trials are needed to establish the effectiveness of nutraceutical treatment, dosage, time of administration and the most favorable combinations of compounds. Therefore, in view of their antioxidant and anti-inflammatory properties, the use of natural products or nutraceuticals for the treatment of stress-related diseases, even including T2D, will be discussed. Several evidences suggest that chronic stress represents one of the main factors responsible for the outcome of T2D.

Effects of adding milk to fermented black mulberry (Morus nigra L.) juice on its antioxidant activity in C2C12 cells and changes in volatile flavor compounds during storage

This study assessed the impact of milk on the bioactive compounds, physicochemical properties, antioxidant activity, ROS inhibition, and volatile flavor compounds of fermented black mulberry juice (FBMJ). Firstly, the results showed that 25% concentration of milk was the most suitable for preparing FBMJ-Milk. Compared to the control group, the addition of milk significantly increased the SOD activity and antioxidant capacity, as well as enhanced the total phenolic content (TPC) and SOD storage stability. Secondly, HS-SPME-GC-MS combined with OPLS-DA analysis identified 49 compounds in FBMJM, including 12 esters, 6 acids, 1 ketone, 2 aldehydes, 19 alcohols and 9 other compounds. During the storage, the levels of ethyl ester compounds decreased significantly, while the degradation of ester produced some acid and alcohol compounds. The findings revealed that the addition of milk was beneficial for maintaining the antioxidant stability of FBMJM during storage and enhancing the richness of product flavor.

Evaluation of Olive Leaf Phenolic Compounds' Gastrointestinal Stability Based on Co-Administration and Microencapsulation with Non-Digestible Carbohydrates

The large generation of olive by-products has motivated their revalorization into high-added-value products. In this regard, olive leaves pose as an interesting source of bioactive compounds, due to their phenolic content with commonly known antioxidant, anti-inflammatory, and immunomodulatory properties, with potential application in non-communicable diseases. However, their effectiveness and applicability into functional foods is limited by their instability under gastrointestinal conditions. Thus, the development of protective formulations is essential. In this study, the spray-drying encapsulation of a phenolic-rich olive leaf extract with inulin as the encapsulating agent was optimized. Then, the behavior of the free extract under gastrointestinal conditions, its co-administration with the encapsulating agent, and the optimized microencapsulated formulation were studied through an in vitro gastrointestinal digestion process following the INFOGEST protocol. Digestion of the free extract resulted in the degradation of most compounds, whereas this was minimized in the co-administration of the non-encapsulated extract with the encapsulating agent. This protective effect, related to its interaction with inulin, was similar to the microencapsulated formulation. Thus, both approaches, co-administration and microencapsulation with inulin, could be promising strategies for the improvement of the stability of these anti-inflammatory and immunomodulatory compounds under gastrointestinal conditions, enhancing their beneficial effect.

Wild and Micropropagated Artemisia eriantha Infusions: In Vitro Digestion Effects on Phenolic Pattern and Antioxidant Activity

This study investigated the in vitro simulated gastrointestinal digestion (GID) effects on wild and micropropagated Apennines Genepì infusions. Wild and micropropagated infusions were compared for their antioxidant activity, phenolic contents, and polyphenolic profiles before and after GID. Before digestion, the wild infusions had higher amounts of phenolic compounds and antioxidant activity than the micropropagated ones. Instead, after digestion, the differences in the total phenolic content (TPC) and antioxidant activity between wild and micropropagated infusions were less pronounced. The changes in the TPC and phenolic profiles revealed the presence of several chemical transformations and rearrangements that resulted in compounds with different reactivity and antioxidant potential. Without enzyme actions, the wild infusion digest undergoes higher modifications than those obtained from the micropropagated ones. The current study offers the first concrete proof of the impact of GID on the polyphenolic chemicals present in infusions of wild and micropropagated Apennines Genepì and their antioxidant properties. Our findings are essential for future in-depth analyses of Apennine Genepì infusions and their potential impacts on human health.

Bioactive Dairy-Fermented Products and Phenolic Compounds: Together or Apart

Fermented dairy products (e.g., yogurt, kefir, and buttermilk) are significant in the dairy industry. They are less immunoreactive than the raw materials from which they are derived. The attractiveness of these products is based on their bioactivity and properties that induce immune or anti-inflammatory processes. In the search for new solutions, plant raw materials with beneficial effects have been combined to multiply their effects or obtain new properties. Polyphenols (e.g., flavonoids, phenolic acids, lignans, and stilbenes) are present in fruit and vegetables, but also in coffee, tea, or wine. They reduce the risk of chronic diseases, such as cancer, diabetes, or inflammation. Hence, it is becoming valuable to combine dairy proteins with polyphenols, of which epigallocatechin-3-gallate (EGCG) and chlorogenic acid (CGA) show a particular predisposition to bind to milk proteins (e.g., α-lactalbumin β-lactoglobulin, αs1-casein, and κ-casein). Reducing the allergenicity of milk proteins by combining them with polyphenols is an essential issue. As potential 'metabolic prebiotics', they also contribute to stimulating the growth of beneficial bacteria and inhibiting pathogenic bacteria in the human gastrointestinal tract. In silico methods, mainly docking, assess the new structures of conjugates and the consequences of the interactions that are formed between proteins and polyphenols, as well as to predict their action in the body.

The potential for the use of leghemoglobin and plant ferritin as sources of iron

Iron is an essential component for the body, but it is also a major cause for the development of many diseases such as cancer, cardiovascular diseases, and autoimmune diseases. It has been suggested that a diet rich in meat products, especially red meat and highly processed products, constitute a nutritional model that increases the risk of developing. In this context, it is indicated that people on an elimination diet (vegetarians and vegans) may be at risk of deficiencies in iron, because this micronutrient is found mainly in foods of animal origin and has lower bioavailability in plant foods. This article reviews the knowledge on the use of leghemoglobin and plant ferritin as sources of iron and discusses their potential for use in vegetarian and vegan diets.

Effect of Medium Chain Triglycerides on the Digestion and Quality Characteristics of Tea Polyphenols-Fortified Cooked Rice

Nowadays, medium chain triglycerides (MCT) with special health benefits have been increasingly applied for fortifying food products. Therefore, the present work aimed to investigate the effects of MCT on traditional tea polyphenols-fortified cooked rice (TP-FCR). It was visualized by DSC, CLSM, XRD, FT-IR, and Raman spectroscopy. The higher content of starch-MCT complexes with an increase in the relative crystallinity and the generation of short-range ordered structures contributed to a more ordered and compact molecular arrangement, which can hinder the action of digestive enzymes on starch. SEM demonstrated that MCT transformed the microstructure of TP-FCR into a denser and firmer character, making it an essential component hindering the accessibility of digestive enzymes to starch granules and slowing the release of tea polyphenols in TP-FCR to attenuate starch digestion. Consequently, the addition of MCT reduced the polyphenol-regulated starch digestibility from 74.28% in cooked white rice to 64.43% in TP-FCR, and further down to 50.82%. Besides, MCT also reduced the adhesiveness and improved the whiteness of TP-FCR. The findings suggested that MCT incorporation could be a potential strategy in cooked rice production to achieve high sensory quality and low glycemic cooked rice.

Multi-nutrient interventions and cognitive ageing: are we barking up the right tree?

As we continue to elucidate the mechanisms underlying age-related brain diseases, the reductionist strategy in nutrition–brain function research has focused on establishing the impact of individual foods. However, the biological processes connecting diet and cognition are complex. Therefore, consideration of a combination of nutritional compounds may be most efficacious. One barrier to establishing the efficacy of multi-nutrient interventions is that the area lacks an established set of evidence-based guidelines for studying their effect on brain health. This review is an output of the International Life Sciences Institute (ILSI) Europe. A multi-disciplinary expert group was assembled with the aim of developing a set of considerations to guide research into the effects of multi-nutrient combinations on brain functions. Consensus recommendations converged on six key issues that should be considered to advance research in this area: (1) establish working mechanisms of the combination and contributions of each individual compound; (2) validate the relevance of the mechanisms for the targeted human condition; (3) include current nutrient status, intake or dietary pattern as inclusion/exclusion criteria in the study design; (4) select a participant population that is clinically and biologically appropriate for all nutritional components of the combination; (5) consider a range of cognitive outcomes; (6) consider the limits of reductionism and the ‘gold standard’ randomised controlled trial. These guiding principles will enhance our understanding of the interactive/complementary activities of dietary components, thereby strengthening the evidence base for recommendations aimed at delaying cognitive decline.

Associations between the New DNA-Methylation-Based Telomere Length Estimator, the Mediterranean Diet and Genetics in a Spanish Population at High Cardiovascular Risk

Biological aging is a relevant risk factor for chronic diseases, and several indicators for measuring this factor have been proposed, with telomere length (TL) among the most studied. Oxidative stress may regulate telomere shortening, which is implicated in the increased risk. Using a novel estimator for TL, we examined whether adherence to the Mediterranean diet (MedDiet), a highly antioxidant-rich dietary pattern, is associated with longer TL. We determined TL using DNA methylation algorithms (DNAmTL) in 414 subjects at high cardiovascular risk from Spain. Adherence to the MedDiet was assessed by a validated score, and genetic variants in candidate genes and at the genome-wide level were analyzed. We observed several significant associations (p < 0.05) between DNAmTL and candidate genes (TERT, TERF2, RTEL1, and DCAF4), contributing to the validity of DNAmTL as a biomarker in this population. Higher adherence to the MedDiet was associated with lower odds of having a shorter TL in the whole sample (OR = 0.93; 95% CI: 0.85-0.99; p = 0.049 after fully multivariate adjustment). Nevertheless, this association was stronger in women than in men. Likewise, in women, we observed a direct association between adherence to the MedDiet score and DNAmTL as a continuous variable (beta = 0.015; SE: 0.005; p = 0.003), indicating that a one-point increase in adherence was related to an average increase of 0.015 ± 0.005 kb in TL. Upon examination of specific dietary items within the global score, we found that fruits, fish, "sofrito", and whole grains exhibited the strongest associations in women. The novel score combining these items was significantly associated in the whole population. In the genome-wide association study (GWAS), we identified ten polymorphisms at the suggestive level of significance (p < 1 × 10-5) for DNAmTL (intergenics, in the IQSEC1, NCAPG2, and ABI3BP genes) and detected some gene-MedDiet modulations on DNAmTL. As this is the first study analyzing the DNAmTL estimator, genetics, and modulation by the MedDiet, more studies are needed to confirm these findings.

Interaction mechanism of carotenoids and polyphenols in mango peels

In this study, carotenoids and polyphenols were demonstrated to be the major active substances in the crude pigment extracts (CPE) of mango peels, accounting for 0.26 mg/g and 0.15 mg/g, respectively. The interactions between carotenoids and polyphenols in CPE was observed, as evidenced by that polyphenols significantly improved the antioxidant activity and storage stability of carotenoids in the CPE. Meanwhile, scanning electron microscopy showed that polyphenols are tightly bound to carotenoids. To further elucidate the interaction mechanism, the monomers of carotenoids and polyphenols were identified by HPLC and LC-MS analysis. Lutein (203.85 μg/g), β-carotene (41.40 μg/g), zeaxanthin (4.20 μg/g) and α-carotene (1.50 μg/g) were authenticated as the primary monomers of carotenoids. Polyphenols were mainly consisted of gallic acid (95.10 μg/g), quercetin-3-β-glucoside (29.10 μg/g), catechin (11.85 μg/g) and quercetin (11.55 μg/g). The interaction indexes between carotenoid and polyphenol monomer of CPE were calculated. The result indicated that lutein and gallic acid showed the greatest synergistic effect on the scavenging of DPPH and ABTS radical, suggesting the interaction between carotenoids and polyphenols in CPE was mainly caused by lutein and gallic acid. Molecular dynamics simulations and thermodynamic parameters analysis demonstrated that hydrogen bonding, electrostatic interactions, and van der Waals forces played dominant roles in the interaction between lutein and gallic acid, which was confirmed by Raman and X-ray diffraction. These results provided a new perspective on the interaction mechanism between carotenoids and polyphenols, which offered a novel strategy for the enhancement of the activities and stability of bioactive substances.

Regulation of main ncRNAs by polyphenols: A novel anticancer therapeutic approach

BACKGROUND

Plant polyphenols have shown promising applications in oncotherapy. Increasing evidence reveals that polyphenols possess the antitumor potential for multiple cancers. Non-coding RNAs (ncRNAs), mainly including small ncRNAs (microRNA) and long ncRNAs (lncRNAs), play critical roles in cancer initiation and progression.

PURPOSE

To establish the modulation of ncRNAs by polyphenols as a novel and promising approach in anticancer treatment.

STUDY DESIGN

The present research employed ncRNA, miRNA, lncRNA, and regulatory mechanism as keywords to retrieve the literature from PubMed, Web of Science, Science direct, and Google Scholar, in a 20-year period from 2003 to 2023. This study critically reviewed the current literature and presented the regulation of prominent ncRNAs by polyphenols. A comprehensive total of 169 papers were retrieved on polyphenols and their related ncRNAs in cancers.

RESULTS

NcRNAs, mainly including miRNA and lncRNA, play critical roles in cancer initiation and progression, which are potential modulatory targets of bioactive polyphenols, such as resveratrol, genistein, curcumin, EGCG, quercetin, in cancer management. The mechanism involved in polyphenol-mediated ncRNA regulation includes epigenetic and transcriptional modification, and post-transcriptional processing.

CONCLUSION

Regulatory ncRNAs are potential therapeutic targets of bioactive polyphenols, and these phytochemicals could modulate the level of these ncRNAs directly and indirectly. A better comprehension of the ncRNA regulation by polyphenols in cancers, their functional outcomes on tumor pathophysiology and regulatory molecular mechanisms, may be helpful to develop effective strategies to fight the devastating disease.

Comparison of dehulling efficiency and grain nutritional parameters of two cultivated barnyard millet species (Echinochloa spp.)

Due to increased awareness regarding the health-promoting profile of millets, inclination towards their consumption has increased considerably. In the Himalayan region of India, cultivars of the two species of barnyard millet, namely Indian (Echinochloa frumentacea) and Japanese barnyard millet (E. esculenta), are grown. To compare the dehulled grain recovery, grain physical parameters, nutritional profile and antioxidant activity, an experiment was carried out at ICAR-VPKAS, Almora, Uttarakhand hills for two years using released and popular cultivars of Indian barnyard millet (VL 207 and VL 172) and Japanese barnyard millet (PRJ-1). The results indicated that the whole grain yield of Japanese barnyard millet cultivar PRJ-1 was significantly higher than Indian Barnyard millet cultivars VL 172 and VL 207; however, the dehulled grain recovery was considerably higher in VL 172 and VL 207 than PRJ-1. Similarly, the physical grain parameters were significantly higher in PRJ-1, but most dehulled grain parameters were at par in cultivars of both species. The nutritional estimation of dehulled grains of both species did not show remarkable differences for most traits. Still, crude fibre, Mn, and Zn were high in PRJ-1, while total digestible nutrients and phosphorous were high in VL 172 and VL 207. Dehulled grains exhibited much more crude protein, ash, minerals, and total digestible nutrients, but the husk accumulated significantly higher crude fibre and total polyphenols.

The Protective Role of Dietary Polyphenols in Urolithiasis: Insights into Antioxidant Effects and Mechanisms of Action

Urolithiasis is a common urological disease with increasing prevalence and high recurrence rates around the world. Numerous studies have indicated reactive oxygen species (ROS) and oxidative stress (OS) were crucial pathogenic factors in stone formation. Dietary polyphenols are a large group of natural antioxidant compounds widely distributed in plant-based foods and beverages. Their diverse health benefits have attracted growing scientific attention in recent decades. Many literatures have reported the effectiveness of dietary polyphenols against stone formation. The antiurolithiatic mechanisms of polyphenols have been explained by their antioxidant potential to scavenge free radicals and ROS, modulate the expression and the activity of endogenous antioxidant and prooxidant enzymes, regulate signaling pathways associated with OS, and maintain cell morphology and function. In this review, we first describe OS and its pathogenic effects in urolithiasis and summarize the classification and sources of dietary polyphenols. Then, we focus on the current evidence defining their antioxidant potential against stone formation and put forward challenges and future perspectives of dietary polyphenols. To conclude, dietary polyphenols offer potential applications in the treatment and prevention of urolithiasis.

Analysis of proanthocyanidins and flavonols in the seedpods of Chinese Antique Lotus: A rich source of antioxidants

Antique Lotus (Nelumbo) is a perennial aquatic plant with unique historical significance and cultural value, whereas its potential economic value hasn't been fully explored. The present study showed that lotus seedpods had significantly higher antioxidant capacity than other parts by FRAP, ABTS, and ORAC assays and analyzed the proanthocyanidins and flavonols in the seedpods of Antique Lotus. Polyphenols contributed to great antioxidant activity and 51 polyphenols were identified by UPLC-TQ-MS analysis. In which, 27 compounds were identified from lotus seedpods for the first time, including 20 trimers, 5 dimers and 2 tetramers of proanthocyanidin. Total proanthocyanidins explained 70%-90% of the different antioxidant activities and the content of proanthocyanidin trimers showed the strongest correlations with the antioxidant activities. This study provided a fundamental reference for the research of polyphenols in lotus and found that Antique Lotus seedpod extracts have the promising prospects of additives used in feed and food processing.

Affinity of Tannins to Cellulose: A Chromatographic Tool for Revealing Structure-Activity Patterns

Food, feed and beverage processing brings tannins into contact with macromolecules, such as proteins and polysaccharides, leading to different chemical and physical interactions. The interactions of tannins with proteins are well known but less is known about the affinity of tannins to polysaccharides. We used bacterial cellulose from nata de coco as a model compound to investigate how tannins and cellulose interact by adsorption measurements using UPLC-DAD. We also explored how the structure of tannins influences these interactions. The model tannins included nine individual structurally different hydrolysable tannins (HTs) and eight well-defined proanthocyanidin (PA) fractions with different monomeric units, mean degree of polymerization and both A- and B-type linkages. Tannins were found to have both strong and weak interactions with bacterial cellulose, depending on the exact structure of the tannin. For HTs, the main structural features affecting the interactions were the structural flexibility of the HT molecule and the number of free galloyl groups. For PAs, prodelphinidins were found to have a higher affinity to cellulose than procyanidins. Similarly to HTs, the presence of free galloyl groups in galloylated PAs and the flexibility of the PA molecule led to a stronger interaction. Adsorption measurements by UPLC-DAD proved to be a sensitive and rapid tool to evaluate the affinity of tannins to cellulose.

The antioxidant capacity and nutrient composition characteristics of lotus (Nelumbo nucifera Gaertn.) seed juice and their relationship with color at different storage temperatures

The effects of different storage temperatures on the nutritional quality, color, and antioxidant capacity of lotus seed juice and the correlations between various physicochemical indices and antioxidant capacity during storage were investigated in this study. The results showed that the overall retention rate of various nutrients and antioxidant activity in lotus seed juice under low-temperature storage was better than that under 37 °C storage. Meanwhile, temperature had a significant effect on increasing the browning of lotus seed juice and the change in L*. The results of Pearson correlation and redundancy analysis (RDA) showed that the reduction in antioxidant activity in lotus seed juice aggravated the browning index of the system at high temperatures. The color changes in the system were closely related to the clarity of lotus seed juice and aging of starch at low temperatures.

Flavor Characterization of Native Xinjiang Flat Peaches Based on Constructing Aroma Fingerprinting and Stoichiometry Analysis

The flat peach is a high economic value table fruit possessing excellent quality and a unique aroma. This article investigated the quality characteristics and aroma fingerprinting of flat peaches (Qingpan, QP; Ruipan 2, R2; Ruipan 4, R4; Wanpan, WP) from Xinjiang in terms of taste, antioxidant capacity, and volatile aroma compounds using high-performance liquid chromatography (HPLC) and HS-SPME-GC-MS. The results showed that the flat peaches had a good taste and high antioxidant capacity, mainly due to the high sugar-low acid property and high levels of phenolic compounds. This study found that sucrose (63.86~73.86%) was the main sugar, and malic acid (5.93~14.96%) and quinic acid (5.25~15.01%) were the main organic acids. Furthermore, chlorogenic acid (main phenolic compound), epicatechin, rutin, catechin, proanthocyanidin B1, and neochlorogenic acid were positively related to the antioxidant activity of flat peaches. All flat peaches had similar aroma characteristics and were rich in aromatic content. Aldehydes (especially benzaldehyde and 2-hexenal) and esters were the main volatile compounds. The aroma fingerprinting of flat peaches consisted of hexanal, 2-hexenal, nonanal, decanal, benzaldehyde, 2,4-decadienal, dihydro-β-ionone, 6-pentylpyran-2-one, 2-hexenyl acetate, ethyl caprylate, γ-decalactone, and theaspirane, with a "peach-like", "fruit", and "coconut-like" aroma. Among them, 2,4-decadienal, 2-hexenyl acetate, and theaspirane were the characteristic aroma compounds of flat peaches. The results provide a theoretical basis for the industrial application of the special aroma of flat peaches.

Co-delivery of curcumin and quercetin in shellac nanocapsules for the synergistic antioxidant properties and cytotoxicity against colon cancer cells

Synergistic bioactivity of dietary polyphenols can enhance functional food development to prevent chronic diseases like cancer. In this study, physicochemical properties and cytotoxicity of curcumin and quercetin co-encapsulated in shellac nanocapsules at different mass ratios were investigated and compared to nanocapsules with one polyphenol and their unencapsulated counterparts. At curcumin and quercetin mass ratio of 4:1, encapsulation efficiency was approximately 80% for both polyphenols, and the nanocapsules showed the highest synergistic antioxidant properties and cytotoxicity for HT-29 and HCT-116 colorectal cancer cells. The nanocapsules had discrete structures smaller than 50 nm and remained stable during 4-week refrigerated storage, and the encapsulated polyphenols were amorphous. After simulated digestions, 48% of the encapsulated curcumin and quercetin were bioaccessible, the digesta retained nanocapsule structures and cytotoxicity, and the cytotoxicity was higher than nanocapsules with only one polyphenol and free polyphenol controls. This study provides insights on utilizing multiple polyphenols as promising anti-cancer agents.

Mechanistic studies of polyphenols reducing the trypsin inhibitory activity of ovomucoid: Structure, conformation, and interactions

Ovomucoid (OVM) is a critical anti-nutritional factor in egg, which may reduce nutrient utilization. In this study, the effects of polyphenols on the trypsin inhibitory activity (TIA) of OVM were investigated by exploring the structural changes and interaction mechanisms. The results found that TIA decreased to 62.34% and 90.41% as epigallocatechin gallate (EGCG) and gallic acid (GA) were added individually. EGCG and GA interacted with OVM via static quenching and hydrophobic interaction. They induced a transition of OVM conformation from disorder to order. Infrared and fluorescence quenching analysis showed that the interaction between EGCG or GA and OVM was spontaneous, and hydrophobic interaction was the predominant force. The mechanism suggested that polyphenols affect the protein conformation by spontaneously binding to OVM in hydrophobic interactions, and lowering the TIA through reduced hydrophobicity. In summary, EGCG may be a promising OVM trypsin activity inactivator, which could also guarantee safety of egg products.

Effects of Hydrogen Sulfide on Sugar, Organic Acid, Carotenoid, and Polyphenol Level in Tomato Fruit

Hydrogen sulfide (H₂S) is known to have a positive effect on the postharvest storage of vegetables and fruits, but limited results are available on its influence in fruit flavor quality. Here, we presented the effect of H₂S on the flavor quality of tomato fruit during postharvest. H₂S decreased the content of fructose, glucose, carotene and lycopene but increased that of soluble protein, organic acid, malic acid and citric acid. These differences were directly associated with the expression of their metabolism-related genes. Moreover, H₂S treatment raised the contents of total phenolics, total flavonoids and most phenolic compounds, and up-regulated the expression level of their metabolism-related genes (PAL5, 4CL, CHS1, CHS2, F3H and FLS). However, the effects of the H₂S scavenger hypotaurine on the above flavor quality parameters were opposite to that of H₂S, thus confirming the role of H₂S in tomato flavor quality. Thus, these results provide insight into the significant roles of H₂S in tomato fruit quality regulation and implicate the potential application of H₂S in reducing the flavor loss of tomato fruit during postharvest.

Biosensors Based on Phenol Oxidases (Laccase, Tyrosinase, and Their Mixture) for Estimating the Total Phenolic Index in Food-Related Samples

Plant phenolic compounds demonstrate bioactive properties in vitro and/or in vivo, which creates demand for their precise determination in life sciences and industry. Measuring the concentration of individual phenolic compounds is a complex task, since approximately 9000 plant phenolic substances have been identified so far. The determination of the total phenolic content (TPC) is less laborious and is used for the qualimetric evaluation of complex multicomponent samples in routine analyses. Biosensors based on phenol oxidases (POs) have been proposed as alternative analytical devices for detecting phenolic compounds; however, their effectiveness in the analysis of food and vegetal matrices has not been addressed in detail. This review describes catalytic properties of laccase and tyrosinase and reports on the enzymatic and bienzymatic sensors based on laccase and tyrosinase for estimating the total phenolic index (TPI) in food-related samples (FRSs). The review presents the classification of biosensors, POs immobilization, the functions of nanomaterials, the biosensing catalytic cycle, interference, validation, and some other aspects related to TPI assessment. Nanomaterials are involved in the processes of immobilization, electron transfer, signal formation, and amplification, and they improve the performance of PO-based biosensors. Possible strategies for reducing interference in PO-based biosensors are discussed, namely the removal of ascorbic acid and the use of highly purified enzymes.

Plum supplementation and lipid profile: a systematic review and meta-analysis of randomised controlled trials

Plums are abundant in bioactive compounds which have been associated with numerous health benefits. In the present study, we aimed at examining the impact of plum supplementation on lipid profile of individuals. Electronic bibliographical databases were searched for relevant randomised clinical trials. Articles meeting our eligibility criteria were included for data extraction and final analysis. Weighted mean difference (WMD) was estimated using a random-effect model. Of the total articles retrieved in the initial search, nine articles were found to be eligible to be included in the analysis. Our results show that plum supplementation significantly improves total cholesterols levels in the unhealthy individuals. Moreover, plum supplementation reduces the LDL-c levels in the pooled sample (WMD = -11⋅52 mg/dl; 95 % CI -21⋅93, -1⋅11, P = 0⋅03, I ² = 98⋅7 %) and also in some of the subgroups of individuals (dried plum, unhealthy subjects, duration more than 8 weeks). Moreover, it had a significant reducing effect on TC levels just in unhealthy subjects. Although plum supplementation did not have any significant impact on serum levels of TG nor HDL-c. Our results show that supplementation with plums is potentially effective in reducing serum total cholesterol and LDL-c.

Nanoencapsulation and bioaccessibility of polyphenols of aqueous extracts from Bauhinia forficata link

Bauhinia forficata Link is a plant rich in polyphenols that has been used mainly for its hypoglycemic activity, which is related to its antioxidant and anti-inflammatory potential. However, the beneficial effect of these bioactive compounds is directly dependent on their bioaccessibility and bioavailability, requiring processing techniques that can improve and preserve their biological activities. This work aimed to obtain nanocapsulated extracts from the infusion (ESIN) and decoction (ESDC) of B. forficata Link leaves, by spray drying. The encapsulating agents used were maltodextrin and colloidal silicon dioxide. The nanocapsules were characterized by HPLC-PDA-ESI-IT-MS ⁿ , evaluated the bioaccessibility of polyphenols after simulated digestion and their antioxidant activity. Additionally, an extensive physicochemical characterization of the nanocapsulated extracts was carried out and their stability and technological parameters were evaluated. The ESIN and ESDC extracts had yields of 57.3 % and 62.7 %, with average nanocapsules sizes of 0.202 μm and 0.179 μm, low humidity and water activity (<0.5), powder density and proper flow properties (Hausner ratio ≤ 1.25; Carr index 18-19 %). Scanning electron microscopy showed a spherical and amorphous morphology and low viscosity, which may have favored the solubility profile. The phenolic compounds of the nanocapsules degraded after 400 °C, showing high thermal stability. The infrared spectra identified the presence of maltodextrin and phenolic compounds and that there were no reactions between them. Chromatography confirmed the presence of phenolic compounds, mainly flavonols and their O-glycosylated derivatives, as well as carbohydrates, probably maltodextrin. Simulated in vitro digestion showed that polyphenols and flavonoids from ESIN and ESDC nanocapsules were bioaccessible after the gastric phase (49.38 % and 64.17 % of polyphenols and 64.08 % and 36.61 % of flavonoids) and duodenal (52.68 % and 79.06 % of polyphenols and 13.24 % and 139.03 % of flavoids), with a variation from 52.27 % to 70.55 % of the antioxidant activity maintained, by the ORAC method, after gastric digestion and still 25 %, after duodenal. Therefore, the nanoencapsulation of extracts of B. forficata is a viable option for the preservation of their bioactive compounds, making them bioaccessible and with antioxidant activity, which make them suitable for incorporation into various nutraceutical formulations, such as capsules, tablets and sachets.

Boosting the Bioaccessibility of Dietary Bioactives by Delivery as Protein-Polyphenol Aggregate Particles

Protein-polyphenol aggregate particles concurrently fortify a functional food product with healthy dietary proteins and concentrated polyphenols. However, what impact does ingestion of aggregate particles have on ultimate health relevance of either the polyphenolic molecules in the matrix or the protein molecules? Because human health benefits are contingent on bioavailability after ingestion, the fate of these molecules during transit in the gastrointestinal tract (GIT) will dictate their utility as functional food ingredients. This brief review explores diverse applications of protein-polyphenol particles in the food industry and the bioaccessibility of both bioactive polyphenolic compounds and edible proteins. Evidence to date suggests that complexation of phytoactive polyphenolics effectively enhances their health-relevant impacts, specifically because the phytoactives are protected in the protein matrix during transit in the GIT, allowing intact, non-degraded molecules to reach the colon for catabolism at the gut microbiome level, a prerequisite to realize the health benefits of these active compounds.

The SARS-CoV-2 main protease (Mpro): Structure, function, and emerging therapies for COVID-19

The main proteases (M^pro), also termed 3‐chymotrypsin‐like proteases (3CL^pro), are a class of highly conserved cysteine hydrolases in β‐coronaviruses. Increasing evidence has demonstrated that 3CL^pros play an indispensable role in viral replication and have been recognized as key targets for preventing and treating coronavirus‐caused infectious diseases, including COVID‐19. This review is focused on the structural features and biological function of the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) main protease M^pro (also known as 3CL^pro), as well as recent advances in discovering and developing SARS‐CoV‐2 3CL^pro inhibitors. To better understand the characteristics of SARS‐CoV‐2 3CL^pro inhibitors, the inhibition activities, inhibitory mechanisms, and key structural features of various 3CL^pro inhibitors (including marketed drugs, peptidomimetic, and non‐peptidomimetic synthetic compounds, as well as natural compounds and their derivatives) are summarized comprehensively. Meanwhile, the challenges in this field are highlighted, while future directions for designing and developing efficacious 3CL^pro inhibitors as novel anti‐coronavirus therapies are also proposed. Collectively, all information and knowledge presented here are very helpful for understanding the structural features and inhibitory mechanisms of SARS‐CoV‐2 3CL^pro inhibitors, which offers new insights or inspiration to medicinal chemists for designing and developing more efficacious 3CL^pro inhibitors as novel anti‐coronavirus agents.

Insights into Polyphenol-Lipid Interactions: Chemical Methods, Molecular Aspects and Their Effects on Membrane Structures

Plant polyphenols have many potential applications, for example, in the fields of chemical ecology and human and animal health and nutrition. These biological benefits are related to their bioavailability, bioaccessibility and interactions with other biomolecules, such as proteins, lipids, fibers and amino acids. Polyphenol-protein interactions are well-studied, but less is known about their interactions with lipids and cell membranes. However, the affinity of polyphenols for lipid bilayers partially determines their biological activity and is also important from the usability perspective. The polyphenol-lipid interactions can be studied with several chemical tools including, among others, partition coefficient measurements, calorimetric methods, spectroscopic techniques and molecular dynamics simulation. Polyphenols can variably interact with and penetrate lipid bilayers depending on the structures and concentrations of the polyphenols, the compositions of the lipids and the ambient conditions and factors. Polyphenol penetrating the lipid bilayer can perturb and cause changes in its structure and biophysical properties. The current studies have used structurally different polyphenols, diverse model lipids and various measuring techniques. This approach provides detailed information on polyphenol-lipid interactions, but there is much variability, and the results may even be contradictory, for example, in relation to the locations and orientations of the polyphenols in the lipid bilayers. Nevertheless, by using well-characterized model polyphenols and lipids systematically and combining the results obtained with several techniques within a study, it is possible to create a good overall picture of these fascinating interactions.

Chemistry of Protein-Phenolic Interactions Toward the Microbiota and Microbial Infections

Along with health concerns, interest in plants as food and bioactive phytochemical sources has been increased in the last few decades. Phytochemicals as secondary plant metabolites have been the subject of many studies in different fields. Breakthrough for research interest on this topic is re-juvenilized with rising relevance in this global pandemics' era. The recent COVID-19 pandemic attracted the attention of people to viral infections and molecular mechanisms behind these infections. Thus, the core of the present review is the interaction of plant phytochemicals with proteins as these interactions can affect the functions of co-existing proteins, especially focusing on microbial proteins. To the best of our knowledge, there is no work covering the protein-phenolic interactions based on their effects on microbiota and microbial infections. The present review collects and defines the recent data, representing the interactions of phenolic compounds -primarily flavonoids and phenolic acids- with various proteins and explores how these molecular-level interactions account for the human health directly and/or indirectly, such as increased antioxidant properties and antimicrobial capabilities. Furthermore, it provides an insight about the further biological activities of interacted protein-phenolic structure from an antiviral activity perspective. The research on the protein-phenolic interaction mechanisms is of great value for guiding how to take advantage of synergistic effects of proteins and polyphenolics for future medical and nutritive approaches and related technologies.

Nutrient molecule corona: An update for nanomaterial-food component interactions

The adsorption of biological molecules to nanomaterials (NMs) will significantly impact NMs' behavior in complex microenvironments. Previously we proposed the need to consider the interactions between food components and NMs for the evaluation of oral toxicity of NMs. This review updated this concept as nutrient molecule corona, that the adsorption of nutrient molecules alters the uptake of nutrient molecules and/or NMs, as well as the signaling pathways to induce a combined toxicity due to the biologically active nature of nutrient molecules. Even with the presence of protein corona, nutrient molecules may still bind to NMs to change the identities of NMs in vivo. Furthermore, this review proposed the binding of excessive nutrient molecules to NMs to induce a combined toxicity under pathological conditions such as metabolic diseases. The structures of nutrient molecules and physicochemical properties of NMs determine nutrient molecule corona formation, and these aspects should be considered to limit the unwanted effects brought by nutrient molecule corona. In conclusion, similar to other biological molecule corona, the formation of nutrient molecule corona due to the presence of food components or excessive nutrient molecules in pathophysiological microenvironments will alter the behaviors of NMs.

Antioxidant, Antihypertensive, Hypoglycaemic and Nootropic Activity of a Polyphenolic Extract from the Halophyte Ice Plant (Mesembryanthemum crystallinum)

This study aims to determine the potential antioxidant, antihypertensive, hypoglycaemic and nootropic activity of a purified polyphenolic extract from the halophyte ice plant (Mesembryanthemum crystallinum). The ice plant extract showed good antioxidant activity measured by DPPH, ORAC, TEAC, FRAP and ferrous ion chelating activity. Moreover, the extract showed potent ACE, DPP-IV and PEP-inhibitory activity (90.5%, 98.6% and 73.1%, respectively, at a final concentration of 1 mg/mL). The extract was fractionated and the fraction with the highest content of total phenolic compounds showed the highest bioactivity, suggesting that polyphenols could be mainly responsible for the abovementioned activities. The tentative polyphenol identification by HPLC-ESI-QTOF-MS in this fraction revealed that flavones (>65%) are the major group, with apigenin (38%) predominating, followed by diosmin (17.7%) and luteolin (11.9%). They could presumably be the main elements responsible for the enzymatic inhibition activity. Additionally, 4-hydroxybenzoic acid, p-coumaric acid and a hydroxycinnamic acid derivative (2-O-(p-cumaroyl)-l-malic acid) were found in the extract. To our knowledge, this is the first time that some of these activities have been reported for halophyte extracts.