Search Results (837)

Enzymatic browning, primarily catalyzed by polyphenol oxidase (PPO), is a major cause of postharvest losses and quality degradation in fresh-cut fruit and vegetable processing. To control this browning, conventional methods such as sulfite treatment and thermal inactivation have been widely used, yet they increasingly face safety, sensory, and regulatory concerns. Because of this, more attention has been directed toward natural PPO inhibitors from agro-industrial by-products as safer, value-added alternatives. However, current knowledge of PPO inhibition mechanisms and rational inhibitor discovery remains fragmented across the literature, limiting the development of effective and sustainable anti-browning approaches. To address this gap, this review presents an integrated framework that covers (i) the structural and kinetic basis of PPO catalysis at the binuclear copper active site; (ii) the mechanistic classification of reversible and irreversible inhibitors, together with kinetic characterization using IC₅₀, K_i, and nonlinear regression approaches; (iii) computational screening strategies, including molecular docking and molecular dynamics simulations as modern tools for predicting enzyme–inhibitor interactions and prioritizing candidate inhibitors; and (iv) the potential of agro-industrial by-products as renewable sources of natural PPO inhibitors for extending the shelf life of fresh-cut produce. Through this framework, this review provides an integrated perspective to support the rational evaluation and future development of effective, sustainable PPO inhibitors for food processing. Full article

Staphylococcus aureus (S. aureus) remains a major global pathogen and a significant public health concern due to its antibiotic resistance. This has spurred the search for new treatments, resulting in the discovery of two promising targets: FtsZ and FabI. Naturally occurring compounds berberine and lipophilic acids are known to bind these enzymes, respectively. This study aims to improve berberine’s binding affinity for FtsZ and enhance its interaction with FabI by designing hybrid compounds that could serve as dual inhibitors, targeting both active and allosteric sites. Forty-eight hybrids, derived from berberine and lipophilic acids with 10 to 22 carbons, were modeled. Molecular docking against five S. aureus enzyme crystal structures identified six compounds with geranic acid chains (1s, 1t, 1u, 2s, 2t, 2u) that showed the strongest binding. Among these, 2s, 2t, and 1t showed the greatest affinity for FtsZ, while 2u, 1u, and 1s targeted FabI, with binding energies around −8.2 to −10.5 kcal/mol. QSAR models estimated MICs within known inhibitor ranges, implying potential effectiveness. Hydrophobic and flexible features correlated with stronger interactions and activity. ADMET analysis indicated low toxicity for these hybrids. Modifying berberine with lipophilic acids appears to be a promising approach for developing plant-based dual inhibitors against S. aureus. Full article

Background: Osteoarthritis (OA) is a degenerative joint disease characterized by inflammation and cartilage destruction, partly mediated by interleukin (IL)-1β-induced nucle factor (NF)-κB activation. Ectoine (Ec) is a natural osmoprotectant with anti-inflammatory properties; however, its effects on NF-κB signaling in OA remain unclear. This study investigated whether ectoine attenuates IL-1β-induced inflammation in chondrocytes by suppressing NF-κB activation and mitigates OA progression in a rat model. Methods: Primary rat chondrocytes were pretreated with ectoine (0–3.0% w/v) and then stimulated with IL-1β (10 ng/mL). Cell viability was evaluated. RT-qPCR and Western blotting were used to determine the expression of inflammatory markers (inducible nitric oxide synthase [iNOS], cyclooxygenase [COX]-2, tumor necrosis factor [TNF]-α, and matrix metalloproteinase [MMP]-3/13), and NF-κB pathway activity was assessed through p65 phosphorylation and inhibitor of NF-κB alpha (IκBα) degradation. In vivo, OA was induced using the modified Hulth method, followed by intra-articular injection of ectoine alone or combined with hyaluronic acid (HA). Cartilage integrity was assessed using Osteoarthritis Research Society International (OARSI) scoring at 8 weeks. Results: Ectoine at 1.5% significantly inhibited IL-1β-induced NF-κB activation, reducing p65 phosphorylation by 59% and IκBα degradation by 41%. This inhibition decreased proinflammatory mediators (iNOS 43%, COX-2 35%, TNF-α 41%) and matrix-degrading enzymes (MMP-3 23%, MMP-13 31%), while increasing type II collagen by 84%. In vivo, ectoine reduced cartilage erosion (OARSI score: 7.0 vs. 10.2 in OA group). The Ec–HA combination improved cartilage retention by 43% compared with ectoine alone. Conclusions: These preclinical findings suggest that ectoine was associated with reduced NF-κB activation markers and attenuated OA-like changes in rat models. The enhanced effect observed with HA supports further investigation of combined therapeutic strategies for OA management. Full article

Background: Combining natural products with conventional antidiabetic agents to inhibit α-glucosidase activity is an effective strategy for preventing postprandial hyperglycemia. Baicalein, a natural flavonoid with well-documented low toxicity, showed potential synergistic effect with acarbose in diabetic models; however, the synergistic performance and mechanisms of the two agents targeting human maltase–glucoamylase (MGAM) remain unclear. Methods: Recombinant human MGAM-C and MGAM-N were expressed in Pichia pastoris for in vitro inhibition assays. Maltose-loaded mice were used to assess the in vivo hypoglycemic activity and intestinal maltase inhibition. Inhibitor–enzyme interactions were investigated by fluorescence spectroscopy, circular dichroism (CD), multiple molecular docking, and molecular dynamics (MD) simulations. Results: Baicalein potently inhibited MGAM-C and MGAM-N with IC₅₀ values of 20.41 ± 4.80 μM and 14.04 ± 0.94 μM, respectively, and demonstrated a synergistic effect when combined with acarbose. In vivo, co-administration significantly reduced blood glucose levels and suppressed small intestinal maltase activity in maltose-loaded mice. Mechanistic studies revealed that baicalein functions as a non-competitive inhibitor by binding to the allosteric site of MGAM-C via stable hydrogen bonds with residues Ile1716 and Trp1749. This interaction induces conformational changes in the enzyme’s secondary structure and optimizes the hydrophobic microenvironment of the active site, thereby enhancing the binding affinity and hydrogen bond stability of acarbose. These molecular events collectively contribute to the synergistic inhibition of MGAM-C hydrolytic activity. Conclusions: This research revealed the synergistic inhibitory effect of baicalein and acarbose on MGAM and the underlying mechanisms, thereby providing a theoretical basis for developing pharmaceutical formulations to enhance acarbose efficacy. Full article

Streptococcus pneumoniae is the major causative agent of community-acquired pneumonia, one of the main infectious diseases that causes inflammation in the alveoli and leads to significant morbidity and mortality across various age groups. Current treatments are challenged by multidrug-resistant strains of S. pneumoniae, which has led to the reemergence of pneumonia in recent years; therefore, it is pivotal to identify new drug targets. The enzyme chorismate synthase (CS), involved in the shikimate pathway of S. pneumoniae, aids in the synthesis of vital aromatic amino acids and other metabolites required for bacterial viability. The present study identifies natural compounds that can inhibit CS using an in silico approach, including pharmacophore modeling, virtual screening, molecular docking, ADME analysis, and molecular dynamics (MD) simulations. Our results suggest that the identified compounds can bind effectively to the active site of S. pneumoniae CS (SpCS), exhibiting affinities better than the known inhibitor 1-benzofuran-3-one and close to the enzyme’s natural substrate, 5-enolpyruvylshikimate-3-phosphate (EPSP). This study suggests lead natural compounds as promising candidates for further investigation as potential inhibitors for the treatment of pneumonia, offering a novel strategy to combat this resilient pathogen. Full article

This study combines ligand- and structure-based in silico strategies to predict the inhibitory activity of natural flavonoids on the Polo-Like Kinase-1 (PLK-1) enzyme as candidate anticancer agents. This enzyme participates in mitosis and is overexpressed in cancer cells. Furthermore, it has been shown to have important implications for tumor metastasis, and its inhibitors are attractive starting points for drug development. First, classification models are developed using linear discriminant analysis and a multilayer perceptron neural network. Models with accuracy greater than 80%, validated using standard statistical performance metrics and applicability domain, are used for virtual screening identifying four compounds as potential antitumor drugs. Subsequently, the identified compounds are evaluated using a molecular docking methodology to verify their binding mode and interactions with the catalytic domain of PLK-1. Finally, the integration of molecular dynamics simulations, at 300 ns, with Molecular Mechanics/Generalized Born Surface Area (MM/GBSA) thermodynamic calculations demonstrates that the hydroxylation pattern of ring B in the flavonol scaffold is the fundamental chemical-structural determinant of electrostatic interactions and the architecture of water-mediated networks. Among the evaluated flavonoids, myricetin showed the most favorable overall computational profile, including the highest virtual-screening score and the most favorable mean MM/GBSA estimate, supporting its prioritization for experimental evaluation as a potential PLK-1 inhibitor. The integration of these approaches offers a robust methodological framework for proposing candidates with a higher probability of success, in subsequent stages of experimental validation, reducing time and costs in the early stages of drug development. Full article

Chalcones are naturally occurring open-chain flavonoids widely distributed in plants and recognized for their broad spectrum of pharmacological activities. Their versatile scaffold allows for extensive structural modifications, leading to a diverse range of natural and synthetic derivatives with notable biological potential. In the context of viral infections, chalcones have demonstrated remarkable efficacy against a variety of human pathogens, including dengue virus, HIV, HCV, influenza A, SARS-CoV-2, and other emerging viruses. Beyond human health, several chalcones have shown potent activity against plant viruses such as tobacco mosaic virus (TMV) and cucumber mosaic virus (CMV), and animal viruses including porcine reproductive and respiratory syndrome virus (PRRSV) and mammalian reovirus (MRV), underscoring their broad antiviral spectrum. These compounds act through multiple mechanisms, including the inhibition of viral enzymes (e.g., proteases, polymerases, and integrases), interference with viral entry and replication, and the modulation of host-related pathways. Recent advances in molecular docking, structure–activity relationship (SAR) studies, and synthetic optimization have further highlighted chalcones as a promising scaffold for antiviral drug discovery. Accordingly, this review summarizes and categorizes antiviral chalcones reported over the last two decades, emphasizing and critically discussing their molecular targets, mechanisms of action, and pharmacological potential as lead compounds. It also provides a comparative perspective on their pharmacological relevance by correlating their activities against standard therapeutic agents and reference inhibitors. Furthermore, the most recurrent viral targets were critically discussed regarding their conservation, expected genetic barriers to resistance, and the global SAR trends identified for the corresponding antiviral chalcones. Finally, in silico ADMET profiling of the most promising naturally occurring chalcones was performed to evaluate their drug-likeness and pharmacokinetic properties, offering guidance for future structural optimization and translational development. Collectively, these findings highlight the chalcone scaffold as a versatile platform for the development of novel antiviral agents targeting diverse viral and host pathways. Full article

Among cardiovascular diseases, myocardial infarction (MI) has become one of the leading causes of mortality worldwide, and the prevalence is anticipated to rise considerably in the coming years. Within non-surgical procedures, chemical drugs, including diuretics, vasodilators, calcium channel blockers, ꞵ blockers, angiotensin converting enzyme inhibitors, are now a well-established option to treat MI progression. However, these drugs are not developed to mitigate oxidative stress directly, which has been recently proven to contribute to MI advancement. Naturally occurring antioxidant compounds possess promising cardioprotective properties and have the potential to be used both as lead compounds for finding novel drugs and complementary therapy to manage MI. While some of them, namely quercetin, puerarin, α-lipoic acid, and curcumin, have already made their way up to clinical trials, numerous compounds have not been sufficiently investigated clinically. To develop and formulate natural antioxidant compounds as drugs against MI, it is crucial to comprehend their underlying mechanisms of cardio-protective activities and structure–activity relationships (SARs). This comprehensive review sheds light on the contribution of oxidative stress in the pathogenesis and progression of Myocardial Infarction, and highlights the cardio-protective roles of 51 natural antioxidant compounds along with their mechanistic insights and SAR. Full article

Seasonal epidemics and high variability of influenza viruses pose a severe threat to global public health security. Neuraminidase, a key functional enzyme in the life cycle of influenza viruses, represents an important target for anti-influenza drug development. Given the continuous emergence of drug-resistant strains against first-line clinical neuraminidase inhibitors (NAIs) such as oseltamivir, there is an urgent need to develop novel, broad-spectrum, and resistance-overcoming NAIs. Natural products, characterized by structural diversity and a wide range of biological activities, provide abundant resources for the discovery of new NAIs. Recent advances in computer-aided drug design, intelligent analytical platforms, and modern screening technologies have accelerated the identification of natural product-derived NAIs. In particular, biosensor-based strategies, including electrochemical, fluorescence, bioluminescence, and surface-enhanced Raman scattering biosensors, have demonstrated significant advantages in sensitivity, selectivity, rapid response, and high-throughput screening. In combination with computational methods and experimental approaches such as affinity ultrafiltration and activity-guided separation, these technologies have promoted the development of intelligent, precise, and multimodal screening platforms. Looking forward, the integration of biosensor-based high-throughput screening platforms with artificial intelligence algorithms is expected to drive the next generation of natural product screening platforms and facilitate the efficient discovery and clinical translation of novel NAIs. This paper systematically reviews the research progress of screening strategies for natural product-derived NAIs; introduces representative natural active NAIs, including phenols, terpenoids, and alkaloids; and prospects future development directions, aiming to provide a scientific reference for the efficient discovery of NAIs from natural products. Full article

Ethylene biosynthetic enzymes, 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS) and ACC oxidase (ACO), participate in the floral sex differentiation of bitter gourd (Momordica charantia). However, the relationship between their structural features and developmental expression patterns remains to be further clarified. In this study, eight McACS and five McACO genes were identified using the Dali-11 reference genome. AlphaFold 3-based modeling showed structural differences between the two families, particularly regarding the diverse C-terminal flexibilities of McACS proteins. Targeted qRT-PCR profiling during the critical 1.0–3.0 mm early floral bud stage revealed that McACS7, a structurally stable Type III member, along with McACS1, McACS12, and McACO2, were significantly upregulated during natural female flower development. Furthermore, treatment with silver nitrate (AgNO₃), an ethylene perception inhibitor, suppressed the transcription of these synthesis genes to basal levels and induced hermaphroditic flower formation. Instead of fully elucidating the downstream molecular mechanisms, these findings provide robust candidate-gene evidence and transcriptional profiling that link the ethylene biosynthetic machinery to the chemically induced sex reversal process, thereby laying a solid foundation for future functional characterization. Full article

This study aims identify plant-derived compounds that can inhibit glutathione peroxidase 4 (GPX4) enzyme and evaluate them through molecular docking, dynamics simulations, and ADMET analyses. The 3D structure of the GPX4 protein (PDB ID: 2OBI) was obtained from the Protein Data Bank. The plant-derived ligand library was compiled from the PubChem database and screened for compliance with Lipinski’s rules using ADMETLAB 2.0. Molecular docking simulations were performed using Autodock Vina. Molecular dynamics simulations of 100 nanoseconds were performed for the selected ligand–protein complexes using AMBER Tools and OpenMM software. The ADMET properties of the ligands were evaluated using the pKCSM web server. Compared to the reference inhibitor RSL3 (−7.2 kcal/mol), five plant compounds showed stronger binding affinity: withaferin A (−8.0 kcal/mol), mahanine (−7.9 kcal/mol), pseudobufarenogin (−7.8 kcal/mol), cucurbitacin I (−7.6 kcal/mol), and liquiritin (−7.5 kcal/mol). Molecular dynamics simulations showed that the complexes of withaferin A, mahanine, and liquiritin exhibited superior structural stability. ADMET analysis revealed that the compounds generally possess acceptable pharmacokinetic profiles but require some bioavailability optimization. The identified plant-derived compounds can be considered as potential therapeutic agents in cancer treatment by inducing ferroptosis via GPX4 inhibition. These findings provide an important basis for natural product-derived drug discovery studies. Full article

Anti-nutritional factors (ANFs) in terrestrial plant feeds constrain efficient herbivore production, an issue intensified by rising feed costs and growing demand for animal products. Unlike previous reviews that focus on single ANFs or feed types, this review provides an integrated, cross-species framework linking ANF chemistry, rumen microbial interactions, and mitigation strategies. It examines major ANF classes—tannins, phytates, saponins, oxalates, protease inhibitors, lectins, glucosinolates, and gossypol—and their distribution and biochemical modes of action. Mechanistic pathways are grouped into digestive effects (reduced palatability and enzyme inhibition), microbial effects (altered rumen microbiota and fermentation), metabolic effects (impaired absorption), and mineral interactions (nutrient complexation and chelation). Species-specific responses are evaluated, emphasizing the partial detoxification capacity of the rumen microbiome and the dose-dependent nature of ANF effects. Mitigation strategies—physical, chemical, microbial, enzymatic, probiotic, and genetic—are critically assessed for efficacy, scalability, and sustainability. Emerging metabolomic and metagenomic evidence shows that certain ANFs confer functional benefits at controlled doses; for example, tannins improve nitrogen retention, saponins reduce methane, and phytic acid scavenges free radicals. This synthesis supports strategic management rather than complete elimination, informing safe and sustainable use of terrestrial feeds under evolving food-security and environmental challenges. Full article

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterised by persistent synovitis, progressive cartilage destruction and bone erosion. Recent advances in single-cell and spatial omics, together with immunometabolic studies, have revealed marked state heterogeneity among synovial macrophages in RA. Their metabolic reprogramming appears to sustain pathogenic cellular states, drive aberrant intercellular communication and impair the resolution of inflammation. Rather than acting as an independent initiating factor, it more likely operates as a downstream amplifier of disease. In this review, we outline the principal functional states and metabolic features of synovial macrophages in health and RA. We focus on how the rewiring of glucose, lipid and amino acid metabolism links inflammatory transcription, tissue remodelling and bone destruction. These connections are mediated by metabolic enzymes, metabolic intermediates, redox regulation and epigenetic modifications. We further summarise the immunometabolic effects of currently available antirheumatic drugs. We also appraise the preclinical evidence and translational limitations of metabolic pathway inhibitors, natural products and nanodelivery systems. It should be noted that most existing evidence still relies on in vitro polarisation systems and rodent models. Validation of metabolic flux, cell-state specificity and causal relationships in human synovium remains limited. As a narrative review focused on recent studies of synovial macrophage metabolism in health and inflammation, this work aims to delineate how metabolic reprogramming shapes the phenotypic heterogeneity and pathogenic functions of macrophages in RA. It also seeks to appraise the potential value and current boundaries of evidence for therapeutically targeting macrophage metabolism. Full article

Artemisia campestris is a medicinal plant species endemic to Algeria, particularly abundant in the southern regions and the central Sahara. Its long-standing use in traditional medicine has recently gained scientific attention, prompting further investigation into its bioactive potential. This study focuses on the phytochemical composition and biological activity of its hydromethanolic extract, with a particular emphasis on its ability to inhibit neural enzymes associated with insect physiology with particular relevance to Aphis gossypii (Glover), a major polyphagous agricultural pest. Preliminary screening revealed a diverse array of secondary metabolites, including tannins (catechic and gallic), flavonoids, quinones, glycosides, terpenoids, saponins, coumarins, and alkaloids; however, anthocyanins were not detected. Quantitative analysis confirmed high concentrations of total phenolics (80.91 ± 1.58 mg GAE/g), flavonoids (60.45 ± 2.02 mg RE/g), phenolic acids (4.24 ± 0.38 mg CAE/g), and condensed tannins (2.26 ± 0.29 mg CE/g). Enzyme inhibition assays were performed using Ellman’s method, and IC₅₀ values were calculated by nonlinear regression analysis based on dose–response curves. The extract demonstrated significant in vitro inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), with IC₅₀ values of 13.79 ± 0.79 µg/mL and 8.34 ± 0.58 µg/mL, respectively. Molecular docking analyses further confirmed strong binding affinities of cyanidin-3-O-glucoside, malvidin-3-O-glucoside, and apigenin (−8.20 to −8.50 kcal/mol) with the AChE active site, stabilized by hydrogen bonding and π–π interactions with key residues. These results were benchmarked against galantamine, a reference inhibitor, which exhibited IC₅₀ values of 1.50 ± 0.12 µg/mL under the same conditions. Although galantamine showed superior potency, the relatively low IC₅₀ values of the A. campestris extract support its potential as a natural cholinesterase-inhibitory agent warranting further investigation. These findings suggest that A. campestris may represent a promising source of natural cholinesterase inhibitors with potential relevance for eco-friendly insect control. These in vitro and in silico findings provide a mechanistic rationale warranting future in vivo bioassay validation against A. gossypii and related agricultural pests. Full article

Biofilms are structured communities of microorganisms embedded in a self-produced extracellular polymeric substance (EPS) matrix, whose development significantly enhances microbial resistance to antibiotics, disinfectants, and host immune defenses, posing major challenges in clinical, industrial, and environmental settings. Compared with planktonic cells, biofilm-associated microorganisms can exhibit up to 10- to 1000-fold increased tolerance to antimicrobial agents, contributing to the persistence of biofilm-associated infections (BAIs). These infections remain difficult to eradicate due to reduced penetration, altered metabolic states, and the presence of dormant or persister cells. Anti-biofilm strategies can be broadly classified into physical approaches (e.g., ultrasound, mechanical stress, and light-based approaches) that target biofilm structure; chemical and enzymatic methods (e.g., EPS-degrading enzymes) that destabilize the matrix; and biological and molecular strategies (e.g., quorum-sensing (QS) inhibitors, anti-virulence agents, bacteriophages, phage-derived antimicrobial molecules, antimicrobial peptides, and natural bioactive compounds) that modulate biofilm development and integrity by targeting regulatory pathways and matrix stability through distinct mechanisms of action. Natural compounds, including lactoferrin, lactoferrin-derived peptides, and probiotic and postbiotic fractions of lactic acid bacteria (LAB), as well as plant-derived metabolites, have shown promising anti-biofilm effects, with efficacy often enhanced through complementary or potentially synergistic interactions. However, despite these advancements, clinical translation remains limited. For example, BAIs account for approximately 80% of chronic infections, with high recurrence rates and therapeutic failure reported in device-associated infections and chronic wounds. These limitations highlight the need for clinically translatable, multimodal approaches that integrate structural biofilm disruption, antimicrobial targeting, and host response modulation to design more effective and sustainable anti-biofilm strategies. Full article