Insight of Stability of Procyanidins in Free and Liposomal Form under an in Vitro Digestion Model: Study of Bioaccessibility, Kinetic Release Profile, Degradation, and Antioxidant Activity

Food-Grade Microwave-Assisted Depolymerization of Grape Seed Condensed Tannins: Optimizing the Reaction Using Gallic Acid as a Nucleophile

Food waste has a significant social impact but can be revalued as a source of bioactive compounds, such as condensed tannins. This abundant biomass, corresponding to a polymeric antioxidant, must be depolymerized to become bioavailable. Previous studies have investigated polymer degradation into oligomers using high temperatures and expensive nucleophiles, often under conditions unsuitable for food applications. In the present investigation, it is proposed that the depolymerization of condensed tannins can occur under food-grade conditions using a Generally Recognized as Safe (GRAS) solvent by optimizing the reaction's heating method with microwave assistance and using gallic acid as a nucleophile. Thermal studies indicate that the degradation of total polyphenols content follows first-order kinetics and occurs above 80 °C in microwave. Depolymerization follows second-order kinetics, yielding epicatechin as the primary product with zero-order formation kinetics. The optimized factors were 80% v/v ethanol, 10 mg/mL polymeric tannins, and 5.88 mg/mL gallic acid. Under these conditions, the reaction efficiency was 99.9%, the mean particle diameter was 5.7 nm, the total polyphenols content was 297.3 ± 15.9 EAG mg/g, and the inhibition of ABTS●+ and DPPH● radicals was 93.5 ± 0.9% and 88.2 ± 1.5%, respectively. These results are promising for future scaling processes.

Correlation between Antioxidant Capacity and Phenolic Compounds of Korean Red Pine (Pinus densiflora Sieb. et Zucc.) Bark Fractions under In Vitro Gastrointestinal Digestive Conditions

This study investigated the correlations between phenolic compounds and antioxidant capacities of Korean red pine (Pinus densiflora Sieb. et Zucc.) bark (RPB) fractions after in vitro gastrointestinal digestion. RPB extracts were prepared using 70% (v/v) aqueous ethanol and further fractionated with n-hexane, ethyl acetate, and water. Their antioxidant capacities were evaluated using three assays. Phenolic compounds were quantified using a liquid chromatography system to assess their stability. The antioxidant capacities of RPB extract and its fractions were significantly influenced by the digestive process. Gastric digestion increased the contents of procyanidin B1 and catechin, whereas intestinal digestion degraded most of the phenolic compounds except protocatechuic acid. Principal component analysis revealed that taxifolin had the greatest impact on data variability, indicating that this polyphenol plays an important role in the antioxidant capacity of RPB. This study provides insights into the stability and bioaccessibility of phenolic compounds in RPB under simulated gastrointestinal conditions, supporting its potential use as a source of natural antioxidants in dietary supplements.

Enhancing stability, bioavailability and nutritional intervention effect of procyanidins using bio-based delivery systems: A review

Procyanidins (PCs), a kind of polyphenolic compound, have attracted extensive attention due to their strong antioxidant, anti-inflammatory and other activities. However, PCs are susceptible to complex micro-environments, resulting in low stability, poor target tissue delivery and bioavailability, which limits their biological effects. Therefore, it is urgent to find some suitable pathways to protect PCs, avoid their degradation, and maximize their health benefits in nutritional intervention. This review focused on the design and construction of different types of bio-based delivery systems loaded with PCs, such as nanoparticles, microparticles, emulsions, liposomes, hydrogels and fibers. The advantages and biological effects of PCs-based delivery systems in promoting cellular uptake, realizing targeted release of organs, cells and organelles, and even nutritional intervention for different chronic diseases were summarized. Furthermore, the development prospects and challenges of delivery systems in the field of precision nutrition were discussed. The construction of these delivery systems can effectively improve the stability and bioavailability of PCs, and maximize their precise nutritional intervention for various chronic diseases.

Physical Properties of Cellulose Derivative-Based Edible Films Elaborated with Liposomes Encapsulating Grape Seed Tannins

Combined use of edible films (EF) with nanoencapsulation systems could be an effective alternative for improving the films' physical properties and maintaining bioactive compounds' stability. This research work focuses on the combined use of EF of cellulose-derived biopolymers enriched with liposomes that encapsulate grape seed tannins and on the subsequent evaluation of the physical properties and wettability. Tannin-containing liposomal suspensions (TLS) showed 570.8 ± 6.0 nm particle size and 99% encapsulation efficiency. In vitro studies showed that the release of tannins from liposomes was slower than that of free tannins, reaching a maximum release of catechin of 0.13 ± 0.01%, epicatechin of 0.57 ± 0.01%, and gallic acid of 3.90 ± 0.001% over a 144 h period. Adding liposomes to biopolymer matrices resulted in significant decrease (p < 0.05) of density, surface tension, tensile strength, elongation percentage, and elastic modulus in comparison to the control, obtaining films with greater flexibility and lower breaking strength. Incorporating TLS into EF formulations resulted in partially wetting the hydrophobic surface, reducing adhesion and cohesion compared to EF without liposomes. Results indicate that the presence of liposomes improves films' physical and wettability properties, causing them to extend and not contract when applied to hydrophobic food surfaces.

Application of In Vitro Digestion Models in the Evaluation of Dietary Supplements

Nowadays, dietary supplements are a permanent part of our diet. Using various simulated in vitro digestive models, the bioavailability of dietary supplement ingredients has also been investigated. In most cases, static models are used instead of dynamic ones. This article focuses on the division of applications of in vitro methods, such as assessing the quality of dietary supplements (in chemical and pharmaceutical form), the impact of diet on the assessment of the bioavailability of product ingredients, the impact of supplement ingredients on the state of intestinal microflora, and the development of new products using various encapsulation methods. The review included publications from 2000 to 2024 showing the use of in vitro methods in dietary supplements containing polysaccharides, proteins, elements, vitamins, and bioactive substances, as well as probiotic and prebiotic products. The impact of components in dietary supplements on the human digestive tract and their degree of bioaccessibility were determined through the use of in vitro methods. The application of in vitro methods has also become an effective tool for designing new forms of dietary supplements in order to increase the availability and durability of labile ingredients in these products.

Liposomes delivery systems of functional substances for precision nutrition

Natural bioactive compounds with antioxidant, antimicrobial, anticancer, and other biological activities are vital for maintaining the body's physiological functions and enhancing immunity. These compounds have great potential as nutritional therapeutic agents, but they can be limited due to their poor flavor, color, unstable nature, and poor water solubility, and degradation by gastrointestinal enzymes. Liposomes, as ideal carriers, can encapsulate both water-soluble and fat-soluble nutrients, enhance the bioavailability of functional substances, promote the biological activity of functional substances, and control the release of nutrients. Despite their potential, liposomes still face obstacles in nutrient delivery. Therefore, the design of liposomes for special needs, optimization of the liposome preparation process, enhancement of liposome encapsulation efficiency, and industrial production are key issues that must be addressed in order to develop food-grade liposomes. Moreover, the research on surface-targeted modification and surface functionalization of liposomes is valuable for expanding the scope of application of liposomes and achieving the release of functional substances from liposomes at the appropriate time and site. The establishment of in vivo and in vitro digestion models of nutrient-loaded liposomes, in-depth study of gastrointestinal digestive behavior after liposome ingestion, targeted nutrient release, and deciphering the nutritional intervention of human diseases and positive health promotion are promising fields with broad development prospects.

Gastrointestinal digestion behavior and bioavailability of greenly prepared highly loaded myofibrillar-luteolin vehicle

In this study, the highly loaded myofibrillar protein (MP)-luteolin (Lut) complexes were noncovalently constructed by using green high-pressure homogenization technology (HPH) and high-pressure micro-fluidization technology (HPM), aiming to optimize the encapsulation efficiency of flavonoids in the protein-based vehicle without relying on the organic solvent (i.e. DMSO, ethanol, etc.). The loading efficiency of Lut into MPs could reach 100 % with a concentration of 120 μmol/g protein by using HPH (103 MPa, 2 passes) without ethanol adoption. The in vitro gastrointestinal digestion behavior and antioxidant activity of the complexes were then compared with those of ethanol-assisted groups. During gastrointestinal digestion, the MP digestibility of complexes, reaching more than 70.56 % after thermal treatment, was higher than that of sole protein. The release profile of Lut encapsulated in ethanol-containing and ethanol-free samples both well fitted with the Hixson-Crowell release kinetic model (R2 = 0.92 and 0.94, respectively), and the total phenol content decreased by ≥ 40.02 % and ≥ 62.62 %, respectively. The in vitro antioxidant activity (DPPH, ABTS, and Fe2+) of the digestive products was significantly improved by 23.89 %, 159.69 %, 351.12 % (ethanol groups) and 13.43 %, 125.48 %, 213.95 % (non-ethanol groups). The 3 mg/mL freeze-dried digesta significantly alleviated lipid accumulation and oxidative stress in HepG2 cells. The triglycerides and malondialdehyde contents decreased by at least 57.62 % and 67.74 % after digesta treatment. This study provides an easily approached and environment-friendly strategy to construct a highly loaded protein-flavonoid conjugate, which showed great potential in the formulation of healthier meat products.

Research progress of procyanidins in repairing cartilage injury after anterior cruciate ligament tear

Anterior cruciate ligament (ACL) tear is a common sports-related injury, and cartilage injury always emerges as a serious complication following ACL tear, significantly impacting the physical and psychological well-being of affected individuals. Over the years, efforts have been directed toward finding strategies to repair cartilage injury after ACL tear. In recent times, procyanidins, known for their anti-inflammatory and antioxidant properties, have emerged as potential key players in addressing this concern. This article focuses on summarizing the research progress of procyanidins in repairing cartilage injury after ACL tear. It covers the roles, mechanisms, and clinical significance of procyanidins in repairing cartilage injury following ACL tear and explores the future prospects of procyanidins in this domain. This review provides novel insights and hope for the repair of cartilage injury following ACL tear.

Ultrasonic-assisted nanoencapsulation of kiwi leaves proanthocyanidins in liposome delivery system for enhanced biostability and bioavailability

The poor biostability and bioavailability of proanthocyanidins limit their application. In this study, it was hypothesized that encapsulation in lecithin-based nanoliposomes using ultrasonic technology improves the above properties. Based on preliminary experiments, the effects of lecithin mass ratio (1-9%, wt.), pH (3.2-6.8), ultrasonic power (0-540 W), and time (0-10 min) on biostability and bioavailability of purified kiwi leaves proanthocyanidins (PKLPs) were determined. Nanoliposomes prepared optimally with lecithin (5%, wt.), pH = 3.2, ultrasonic power (270 W), and time (5 min) demonstrated a significantly (p < 0.05) improved physicochemical stability, homogeneity, and high encapsulation efficiency (73.84%) relative to control. The PKLPs bioaccessibility during in vitro digestion increased by 2.28-3.07-fold, with a remarkable sustained release and delivery to the small intestine. Similar results were obtained by in vivo analyses, showing over 200% increase in PKLPs bioaccessibility compared to the control. Thus, PKLPs-loaded nanoliposomes are promising candidates for foods and supplements for novel applications.

Implication of the Polymeric Phenolic Fraction and Matrix Effect on the Antioxidant Activity, Bioaccessibility, and Bioavailability of Grape Stem Extracts

The bioaccessibility and bioavailability of phenolics compounds of two grape stem extracts with different composition were studied. High polymeric extract (HPE) presented a higher content of total phenolics (TPC), procyanidins, hemicelluloses, proteins, and ashes, whereas low procyanidin extract (LPE) showed a higher fat, soluble sugars, and individual phenolic compounds content. Corresponding to its higher total phenolics content, HPE possesses a higher antioxidant activity (TEAC value). The digestion process reduced the antioxidant activity of the HPE up to 69%, due to the decrease of TPC (75%) with a significant loss of polymeric compounds. LPE antioxidant activity was stable, and TPC decreased by only 13% during the digestion process. Moreover, a higher antioxidant phenolic compounds bioavailability was shown in LPE in contrast to HPE. This behaviour was ascribed mainly to the negative interaction of polymeric fractions and the positive interaction of lipids with phenolic compounds. Therefore, this study highlights the convenience of carrying out previous studies to identify the better extraction conditions of individual bioavailable phenolic compounds with antioxidant activity, along with those constituents that could increase their bioaccessibility and bioavailability, such as lipids, although the role played by other components, such as hemicelluloses, cannot be ruled out.

Delivery of Catechins from Green Tea Waste in Single- and Double-Layer Liposomes via Their Incorporation into a Functional Green Kiwifruit Juice

Globally, about one million tonnes of tea products, which contain high concentrations of catechins and their derivatives, are wasted annually. Therefore, green tea waste catechins (GTWCs) are worth extracting, processing, protection, and delivery to the human body. In this study, GTWCs were extracted using a green method and then encapsulated in both single- (SLLs) and double-layer liposomes (DLLs). The encapsulated extracts were subsequently incorporated into a fresh green kiwifruit juice. SLLs and DLLs containing GTWCs had a size of about 180 and 430 nm with a zeta potential of -35 and +25 mV, respectively. Electron microscopy illustrated the separation of the SLLs and fibre in kiwifruit juice and attraction of the DLLs to this fibre. Liposomal GTWCs were effectively maintained in the kiwifruit juice during the 28 days of storage (4 °C), demonstrating the effectiveness of this delivery system for high-value bioactives (i.e., catechins) from such a by-product (i.e., green tea waste).

Rheum ribes extract-loaded nanoliposome as a novel phytogenic antibiotic alternative in mice challenged by Escherichia coli (O157:H7)

This study was performed to compare the noncapsulated with nanoliposome-encapsulated phenolic-rich fraction (PRF) obtained from Rheum ribes as a dietary additive and to assess their health-promoting potentials in the mice infected by enteropathogenic Escherichia coli (O157:H7). Upon fractionation, the ethyl acetate fraction with 46.9 ± 2.17 mg GAE/g DW was found as a highest phenolic content. The PRF successfully loaded into nanoliposome structure with a nanometer in size (193.2 nm) and spherical shape and homogeneous dispersion. The gallic acid, salicylic acid, caffeic acid, cinnamic acid, catechin, ellagic acid, and ferulic acid are bioactive phenolics present in the nanoliposome-loaded PRF; however, the main bioactive compounds are cinnamic acid (911 μg/g DW) and ellagic acid (826 μg/g DW). The infection caused by E. coil impaired the weight gain and food intake, liver function, morpho structural characteristics of jejunum, upregulated the expression of inflammatory genes (Cox2, iNOS), downregulation of antioxidant-related genes (SOD, GPX), and increased the ileal population of E. coil. The addition of nonencapsulated PRF and nanoliposome-encapsulated PRF at the concentration of 10 mg TPC/kg BW/day improved these parameters although the nanoliposome-encapsulated PRF revealed more potential as compared with the nonencapsulated PRF in improving the health parameters in mice. The higher health-promoting activity of nanoliposome-encapsulated PRF could be associated with its enhanced intestinal absorption, bioavailability, bioaccessibility, and bioactivity. Consequently, the nanoliposome-encapsulated PRF could be considered as a promising phytobiotic against E. coil infection in mice.

Encapsulation of bioactive compounds extracted from date palm seeds (Phoenix dactylifera L.) and their use in functional food

Liposomes have been used as a novel phytoconstituent delivery system to encapsulate lyophilized palm seed phenolic extract (PSPE) and incorporate it into yogurt as a food model to enhance the bioavailability of PSPE. Phenolic compounds were extracted with aqueous ethanol from palm seed powder using the solvent-maceration approach assisted by ultrasonication. Lyophilized PSPE (0.2-1% w/v) was enclosed in a liposome structure coated with or without chitosan (primary/secondary liposome). Particle size, zeta potential, encapsulation efficiency (EE), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM) were applied to investigate the primary and secondary liposomes. To assess the in vitro bioaccessibility of PSPE and primary/secondary liposomes, the total phenolic content (TPC) and the antioxidant activity were studied during the oral, gastric, and intestinal digestion stages. Three concentrations of lyophilized secondary liposomes (1.25, 2.5, and 3.75% w/v) were added to the yogurt food model. During the 14 days of storage, the physical, chemical, and sensory properties were assessed. Compared to the primary liposomes (87%), the secondary liposomes (91%) showed a higher encapsulation efficiency. Comparing the secondary liposomes to the original liposomes and the non-encapsulated PSPE, the bioaccessibility of phenolic compounds was improved. Fortified yogurt with secondary liposomes had a lower syneresis and viscosity than the reference yogurt. The encapsulated PSPE provided a good level of protection, and its release increased throughout the intestinal phase. Thus, PSPE in a microencapsulated form has been proven to be a rich and cost-effective source of phenolics that can be used successfully to produce functional yogurt.

The Flavonoid Molecule Procyanidin Reduces Phase Separation in Model Membranes

Procyanidin extracted from fruits, such as apples, has been shown to improve lipid metabolization. Recently, studies have revealed that procyanidin interacts with lipid molecules in membranes to enhance lipid metabolism; however, direct evidence of the interaction between procyanidin and lipid membranes has not been demonstrated. In this study, the phase behaviors and changes in the membrane fluidity of cell-sized liposomes containing apple procyanidin, procyanidin B2 (PB2), were demonstrated for the first time. Phase separation in 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC)/1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)/cholesterol ternary membranes significantly decreased after the addition of PB2. The prospect of applying procyanidin content measurements, using the results of this study, to commercial apple juice was also assessed. Specifically, the PB2 concentrations were 50%, 33%, and 0% for pure apple juice, 2-fold diluted apple juice, and pure water, respectively. The results of the actual juice were correlated with PB2 concentrations and phase-separated liposomes ratios, as well as with the results of experiments involving pure chemicals. In conclusion, the mechanism through which procyanidin improves lipid metabolism through the regulation of membrane fluidity was established.

Liposomal Delivery of Plant Bioactives Enhances Potency in Food Systems: A Review

The potency of plant bioactives may decline drastically upon exposure to harsh external environments including gastrointestinal conditions. The protective role played by liposomes contributes to desirable properties including increased stability, slow/controlled release, improved bioactivity, and enhanced bioavailability of the encapsulated bioactives. Also, the incorporation of plant bioactives encapsulated liposomes in food matrices has resulted in augmented sensory attributes and improved quality of the foods further exhibiting the aptness of liposomal applications in food. Excitingly, new opportunities that circumvent the major shortfalls of utilizing liposomal formulations in the food industry have arisen paving the way to yield food products with high quality.

Antioxidant activity, stability, in vitro digestion and cytotoxicity of two dietary polyphenols co-loaded by β-lactoglobulin

The combination of multiple dietary polyphenols may have synergistic beneficial effects. And the beneficial effects can be further improved by the encapsulation of proteins. The interactions of procyanidin B2 (PB2) and/or dihydromyricetin (DMY) with β-lactoglobulin (β-LG) were investigated using multi-spectroscopic techniques and molecular docking. The structural change of β-LG in the presence of PB2 and/or DMY was demonstrated by dynamic light scattering, Fourier transform infrared spectroscopy and circular dichroism spectroscopy. Response surface analysis was used to optimize the synergistic antioxidant activity between PB2 and DMY. Besides, the antioxidant activity, stability, in vitro digestion and cytotoxicity of PB2 and DMY in the binary and ternary systems were investigated. These studies will elucidate the interaction mechanism of PB2 and/or DMY with β-LG. The research results can provide theoretical support for the development of functional foods and beverages with synergistic activity, improved stability and bioaccessibility, thereby promoting human health and preventing diseases.

Ethanolic extract of Pyrus pashia buch ham ex. D. Don (Kainth): A bioaccessible source of polyphenols with anti-inflammatory activity in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Pyrus pashia Buch ham ex. D. Don (Kainth) fruit from the Himalayan region is traditionally consumed by native people in the form of decoctions for various clinical conditions including inflammatory diseases. However, scientific studies on the biofunctional properties of Kainth fruits are still scarce.

AIM OF THE STUDY

The study is aimed to investigate the anti-inflammatory effects of Kainth fruit extracts using in vitro and in vivo inflammation models.

MATERIAL AND METHODS

Free, esterified and bound fractions from the Kainth ethanolic extracts were prepared for determining the anti-inflammatory effect. The levels of 5-LOX and COX-2 were determined in vitro. The protein levels of cytokines (IL-6, TNF-α & IL-10) were quantitated by ELISA method in lipopolysaccharide-stimulated RAW macrophages. Also, the anti-inflammatory potential of the Kainth fruit extracts was determined using the carrageenan-induced mice paw edema model. The bioaccessibility of Kainth fruit extracts was measured using a simulated in vitro digestion system (salivary, gastric and intestinal).

RESULTS

The Kainth fruit extracts were partially purified to yield free, esterified and bound phenolics. Free and bound phenolics of Kainth fruits inhibited 5-Lipoxygenase, Cyclooxygenase-2 activities and pro-inflammatory cytokines (Interleukin-6 and tumour necrosis factor-α) expression in vitro. Also, oral administration of these extracts to the carrageenan-injected mice showed an anti-inflammatory effect by decreasing the pro-inflammatory cytokines and reducing the cellular infiltration in paw tissues. Also, both the extracts showed better bioavailability and bioaccessibility in in vitro and in vivo studies.

CONCLUSIONS

The results indicated that free and bound phenolics from Kainth fruits that are rich in catechin, epicatechin, arbutin and chlorogenic acid exhibited anti-inflammatory effects and could potentially be used to treat inflammatory diseases.

In vitro gastric bioaccessibility of avocado peel extract in beef and soy-based burgers and its impact on Helicobacter pylori risk factors

The objective of the present study was to investigate the impact of phenolic-rich avocado peel extract (APE) as an ingredient in beef and soy-based burgers to increase their antioxidant activity, reduce lipid and protein oxidation during gastric digestion, and inhibit urease and anhydrase carbonic activity, which are considered as key factors in the main steps of Helicobacter pylori adhesion in the stomach. The gastric bioaccessible fraction of soy and beef burgers with added 0.5% APE obtained by in vitro digestion exhibited a higher content of phenolic compounds, including monomeric and oligomeric (epi)catechin forms and quercetin, and reduced levels of thiobarbituric acid-reactive substances (TBARS) and carbonyls (49% to 73% and 57% to 60%, respectively) when compared with control burgers. Moreover, the burgers with APE inhibited urease and carbonic anhydrase activity. Results generally showed that including APE reduces the primary risk factors associated with H. pylori infection.

One-step dynamic fabrication of asymmetric multi-layered porous films for sustained drug delivery

Asymmetric multi-layered porous films were prepared by casting inverse emulsion following the breath figure method. The porous morphologies both on the surface and in the bulk of the fabricated film could be dynamically manipulated by tuning the emulsion composition as well as the environmental conditions. The model drug was efficiently loaded into the porous film by direct encapsulation during film fabrication, and remarkable sustained drug release from the porous film for more than 28 days was achieved.

pH-Responsive Core-Shell Microparticles Prepared by a Microfluidic Chip for the Encapsulation and Controlled Release of Procyanidins

The purpose of this study was to construct a delivery system using a microfluidic chip to protect procyanidins (PCs) and to achieve their pH-controlled release in simulated gastrointestinal fluid. The microfluidic chip was designed and fabricated to generate water-in-water-in-oil (W/W/O) templates for the preparation of sodium alginate/chitosan microparticles with a uniform size and core-shell structure, using an internal-external gelation method. Compared with free PCs, the stability of PCs embedded in microparticles was improved and a pH stimulus-responsive release of PCs from microparticles was observed under neutral pH conditions. The delivery system of microparticles was nontoxic and showed an inhibitory effect on the decrease of mitochondrial membrane potential in Caco-2 cells caused by H₂O₂ and acrylamide. This work provided a method for fabricating compact microfluidic chips to prepare a pH stimulus-responsive PCs delivery system with improved stability, which may have potential applications in the delivery of other nutrients.

Chitosan decoration improves the rapid and long-term antibacterial activities of cinnamaldehyde-loaded liposomes

In this work, cinnamaldehyde-loaded liposomes decorated with different concentrations of chitosan (0, 0.25, 0.5, 1, 2, 3, and 4 mg/mL) were prepared and their physical and antibacterial properties were evaluated. The results showed that the physical decoration of chitosan improved the encapsulation efficiency and storage stability of the liposomes. Liposomes decorated with chitosan at the concentration of 0.25 to 4 mg/mL were able to achieve an obvious antibacterial efficiency against Staphylococcus aureus after only 10 min of incubation. The antibacterial efficiency of chitosan-decorated liposomes was still higher than 90% after being stored for 28 d when the chitosan concentration was greater than 1 mg/mL. Besides, increasing the chitosan concentration significantly decreased the minimum inhibitory concentration of the liposomes. The comparison of the antibacterial activities and mechanisms of cinnamaldehyde-loaded liposomes decorated with chitosan at a concentration of 4 mg/mL (CH-CL), cinnamaldehyde-loaded liposomes (CL), cinnamaldehyde, and chitosan revealed that chitosan and cinnamaldehyde exerted a cumulative and synergistic bacteriostatic effect in the liposomes. This led to damage to the cell membrane integrity, causing cell death by inducing leakage of intracellular components. These results can potentially provide guidance for the preparation and application of natural preservatives with rapid and long-term bacteriostatic effects.

An NMR-Based Chemometric Strategy to Identify Leishmania donovani Nucleoside Hydrolase Inhibitors from the Brazilian Tree Ormosia arborea

Nucleoside hydrolases are a strategic target for the development of drugs to treat leishmaniasis, a neglected disease that affects 700 thousand to one million people annually. The present study aimed to identify Leishmania donovani nucleoside hydrolase (LdNH) inhibitors from the leaves of Ormosia arborea, a tree endemic to Brazilian ecosystems, through a strategy based on ¹H NMR analyses and chemometrics. The aqueous EtOH extract of O. arborea leaves inhibited LdNH activity by 95%. The extract was fractionated in triplicate (13 in each step, making a total of 39 fractions). Partial least squares discriminant analysis (PLS-DA) was used to correlate the ¹H NMR spectra of the fractions with their LdNH inhibitory activity and thus to identify the spectral regions associated with the bioactivity. The strategy aimed at isolating the probable bioactive substances and led to two new A-type proanthocyanidins, linked to a p-coumaroyl unit (1 and 2), which appeared as noncompetitive inhibitors of LdNH (IC₅₀: 28.2 ± 3.0 μM and 25.6 ± 4.1 μM, respectively). This study confirms the usefulness of the NMR-based chemometric methods to accelerate the discovery of drugs from natural products.

Analysis of β-lactoglobulin–epigallocatechin gallate interactions: the antioxidant capacity and effects of polyphenols under different heating conditions in polyphenolic–protein interactions

A β-Lg-EGCG covalent conjugate is formed by linking the amino group of a lysine residue and EGCG; the antioxidant capacity of EGCG induced by β-Lg–EGCG covalent conjugates causes a significant decrease.