Search Results (852)

Antimicrobial resistance is an emerging challenge in veterinary medicine, particularly in dogs, where bacterial skin infections are highly prevalent. Honey and its bioactive extracts have emerged as potential natural alternatives to conventional antimicrobials. This study evaluated the antimicrobial activity of methanolic extracts from four honey types collected in Central Chile against multidrug-resistant (MDR) bacterial isolates from canine patients, including Enterococcus faecium, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Pasteurella multocida, and Enterobacter cloacae. Antimicrobial potency was assessed by minimum inhibitory concentration (MIC), and phenolics, flavonoids, and antioxidant capacity were quantified. All extracts inhibited bacterial growth, with E. coli, E. faecium and S. aureus being the most susceptible (MIC 3.13% w/v), while Gram-negative bacteria such a P. aeruginosa, P. multocida, and E. cloacae required higher concentrations (MIC 12.5% w/v). Secondary metabolite analysis revealed seasonal and apiary-related variations, with apiary 2 honey showing significantly higher phenolic (195.58 ± 4.28 mg GAE/100 g) and flavonoid (65.46 ± 4.35 mg QE/100 g) contents in summer. In contrast, antioxidant capacity (FRAP) did not differ significantly. These findings indicate that honey’s antimicrobial properties are closely related to its bioactive composition and influenced by season and floral origin, reinforcing its potential as a sustainable alternative to antibiotics in veterinary medicine under the One Health approach. Full article

Phaseolorin J (TT-55), a chromone compound isolated and purified from the fermentation products of Phomopsis asparagi DHS-48, is an endophytic fungus obtained from mangrove forests. Preliminary experimental studies have revealed its potent antioxidant and anti-inflammatory activities, though its mechanism of action remains unclear. In this study, we aimed to investigate the molecular mechanisms underlying the antioxidant and anti-inflammatory effects of TT-55, following initial evidence of its potency, by employing an LPS-induced RAW264.7 macrophage model in vitro. The results revealed that in the LPS-induced inflammatory model of RAW264.7 cells, the TT-55 dose dependently inhibited the expression of LPS-induced inflammatory cytokines (TNF-α, IL-18, IL-1β, IL-6) and the production of oxidative stress markers (reactive oxygen species, SOD, MDA). Following combined treatment with the Nrf2 pathway inhibitor ML385 and TT-55, the inhibitory effects of TT-55 on inflammatory cytokines and oxidative stress markers were reversed by ML385. Meanwhile, ML385 also attenuated the ability of TT-55 to suppress LPS-induced upregulation of NLRP3 inflammasome-related genes. In conclusion, TT-55 may exert its antioxidant and anti-inflammatory effects by activating the Nrf2/HO-1 signaling pathway and suppressing the upregulation of NLRP3 inflammasome-related genes. Full article

Helicobacter pylori (H. pylori) is the primary etiological agent for chronic gastritis, peptic ulcers, and gastric adenocarcinoma. The alarming rise in multidrug-resistant (MDR) strains, particularly against clarithromycin (CLR), metronidazole (MNZ), and levofloxacin (LVX), has severely compromised standard therapies. Thus, there is an urgent clinical need for novel antimicrobial agents that operate through distinct mechanisms to bypass resistance pathways and mitigate gastric cancer risk. We designed and synthesized a series of antimicrobial peptides, focusing on the proteolytically stable all-D-amino acid enantiomer, DT7-3, derived from a probiotic-sourced template. Minimum inhibitory concentrations (MICs) were determined against standard strains and 11 clinical MDR isolates via the broth microdilution method. Antimicrobial mechanisms were elucidated using scanning electron microscopy (SEM) for morphology, fluorescence-based assays for anti-adhesion activity, and real-time qPCR to quantify virulence gene expression (babA, ureA, and vacA). Biocompatibility was assessed using defibrinated sheep erythrocytes, gastric epithelial cells (GES-1), and representative beneficial gut microbiota. Analysis of the clinical isolates revealed resistance rates of 63.6% for CLR/LVX and 81.8% for MNZ, with 54.5% identified as MDR. DT7-3 exhibited superior potency (MIC 1–32 µg/mL) against all strains, significantly outperforming its L-enantiomer counterparts. Mechanistic studies unveiled a “triple-hit” mechanism: (1) rapid membrane disruption; (2) potent inhibition of bacterial adhesion to host cells (~60% reduction at 0.5 × MIC); (3) significant downregulation of critical virulence factors (babA, ureA, and vacA). Furthermore, DT7-3 showed an excellent safety profile, with negligible hemolysis (<5% at 32 µg/mL) and minimal cytotoxicity toward GES-1 cells, yielding a high selectivity index (SI, MHC/MIC) > 32 relative to mammalian cells. Crucially, DT7-3 showed high selectivity for the pathogen over beneficial gut microbiota (MIC > 128 µg/mL, SI > 16). Crucially, DT7-3 maintained potent bactericidal activity (MIC ≤ 16 µg/mL) even under cholesterol-enriched conditions. The engineered D-peptide DT7-3 is a potent candidate for combating MDR H. pylori. Its multifaceted mechanism, targeting bacterial viability while suppressing core virulence factors, positions it as a robust lead compound for next-generation eradication therapies aimed at reducing the burden of H. pylori-associated diseases. Full article

Five previously undescribed steroids, chrysogenones A–E (1–5), were isolated from the deep-sea-derived Penicillium sp. MCCC 3A00121. Their chemical structures were unambiguously established through comprehensive spectroscopic analyses, density functional theory (DFT)-based electronic circular dichroism (ECD) calculations, and X-ray crystallography. Chrysogenones represent a class of oxidatively modified ergosterone-type derivatives, with 1, 2, and 5 featuring an uncommon malonyl substitution at C-12 of the ergosterone skeleton. Biologically, 1–5 exhibited varying degrees of inhibitory activity against renal fibrosis, as evidenced by the downregulation of the key fibrotic markers α-smooth muscle actin (α-SMA) and collagen I (COL1A1). Among them, chrysogenone B (2) emerged as the most promising candidate, demonstrating superior potency and pronounced inhibition of activated NRK-49F cell proliferation. Integrated network pharmacology analysis and molecular docking studies further suggested that the anti-renal fibrotic effects of compound 2 may be mediated through its interaction with putative molecular targets, including AKT1, HSP90AA1, and MDM2. Full article

Medicarpin, a natural pterocarpan phytoalexin, contributes to tree defense against microbial decay, particularly from the aggressive white-rot fungus Trametes versicolor, an ASTM standard for wood durability testing. To improve upon the inhibitory effect of medicarpin against this fungus (150 mg/L), eleven derivatives were synthesized and evaluated. The acetylated analog demonstrated superior activity, achieving complete growth inhibition at 100 mg/L. To establish a structure–activity relationship, molecular docking was performed on the copper cluster on fungal laccase, the primary oxidative enzyme of T. versicolor. The acetylated derivative bound the T1 copper site with a more favorable free energy (−8.5 kcal/mol) than the parent compound, exhibiting enhanced stabilizing interactions and a binding pose anchored closer to the trinuclear copper cluster (TNC). These results were corroborated by 80 ns molecular dynamics simulations, confirming complex stability and the persistence of key interactions. This study demonstrates that targeted chemical modification of natural phytoalexins can significantly improve their antifungal potency. The superior performance of the acetylated medicarpin derivative, linked to optimized binding at the laccase active site, establishes a clear structure–activity relationship and highlights the potential of such engineered compounds as leads for next-generation, bio-inspired wood preservatives. Full article

The essential reaction of CO₂ hydration, fundamental to all living organisms, is facilitated by the enzyme carbonic anhydrase (CA, EC 4.2.1.1). This enzyme plays a crucial role in regulating various physiological and pathological processes. A series of heterocyclic benzenesulfonamide derivatives (19 compounds) were evaluated as possible inhibitors of human CAs. Their inhibitory properties were tested against several isoforms such as the cytosolic hCA I and hCA II, as well as the transmembrane isoforms hCA IV, hCA IX and hCA XII. The tested molecules demonstrated notable inhibitory potential, particularly toward hCA II and hCA IV, where five and four compounds, respectively, exhibited greater potency than the reference inhibitor, acetazolamide. Molecular docking simulations were further performed to elucidate the binding interactions of the most active compounds with the human CA II, IV IX and XII isoforms Full article

Rhizopus oryzae lipase (ROL) is a key enzyme involved in olive oil spoilage and acts as a virulence factor in fungal infections. Natural lipophilic lipase inhibitors are crucial for mitigating economic losses resulting from lipid degradation in stored or decaying olive fruits. This study evaluated a series of enzymatically synthesized piperate esters with varying alkyl chain lengths (butyryl, C4; octyl, C8; dodecyl, C12) for their inhibitory effects on ROL activity. Octyl piperate (C8) demonstrated the highest potency, with IC₅₀ values of 0.05 mg/mL using methods B and C or 0.25 mg/mL using method A. Molecular docking indicated that C8 achieved the most favorable predicted binding energy (Gscore: –11.134 kcal/mol), primarily through hydrophobic interactions (Val329, Ala212, Phe209) and hydrogen bonds with oxyanion hole residues (Ser268, Thr206, Gln241). Molecular dynamics simulations confirmed that C8 maintained stable binding and stabilized the catalytic residues. In comparison, C4 exhibited weaker interactions, and the longer C12 chain induced conformational instability and steric hindrance. These results establish a parabolic structure–activity relationship, identifying the octyl chain (C8) as optimal for ROL inhibition among the tested derivatives. The rational design of lipophilic, biodegradable lipase inhibitors thus positions octyl piperate as a promising candidate for extending olive storage and shelf life, and as a scaffold for developing natural antifungal agents targeting virulent R. oryzae strains. Full article

This study investigates the effects of heliomycin and its derivative LCTA-2614 on both hormone-dependent and hormone-independent breast cancer cell lines. Biological activity was assessed using the MTT assay, flow cytometry, and immunoblotting. Heliomycin exhibited potent antiproliferative activity across breast cancer cell lines of various molecular subtypes, with half-maximal inhibitory concentrations (IC₅₀) of 0.65 μM in MCF7, 0.95 μM in MDA-MB-231, and 0.79 μM in HCC1954 cells. The water-soluble derivative LCTA-2614 showed comparable activity, with IC₅₀ values of 0.86 μM in MCF7, 0.68 μM in MDA-MB-231, and 0.60 μM in HCC1954 cells. The compound LCTA-2614 demonstrated a more selective effect on tumor cells compared to heliomycin. Importantly, both compounds maintained their antiproliferative potency under hypoxic conditions, a known driver of chemoresistance. Additionally, compound LCTA-2614 induced apoptosis in hormone-dependent MCF7 cells through a p53-associated pathways. These findings highlight heliomycin as promising molecular scaffolds for the development of new chemotherapeutic agents. Their retained activity under hypoxia suggests particular potential for the treatment of solid tumors with extensive hypoxic regions. Full article

Neurodegenerative disorders (NDs), such as Alzheimer’s disease and Parkinson’s disease (PD), represent a significant challenge for ageing populations, with their prevalence increasing worldwide. Elevated human Monoamine Oxidase B (hMAO-B) activity has been related to neurodegenerative progression, where it contributes, among others, to oxidative stress and neuroinflammation. The identification and optimization of selective hMAO-B inhibitors is therefore pivotal in addressing the progression of NDs. In this work we introduced 2-aroylbenzothiophene analogues as promising agents to mitigate neurodegeneration. The synthesized compounds were screened against hMAO-A and hMAO-B, identifying compounds 4, 11, and 12 as the most promising. In vitro studies in hGF and SH-SY5Y cells revealed distinct toxicity profiles, with compound 4 being the least tolerated at 100 µM. ROS generation was investigated as a possible mechanism underlying this toxicity. Compounds 4 (12.5 µM), 11, and 12 (100 µM) were further evaluated for neuroprotective effects against 6-hydroxydopamine (6-OHDA)-induced toxicity in SH-SY5Y cells, showing a modest neuroprotective effect after 72 h at a sub-toxic 6-OHDA concentration (250 µM), comparable to the clinically used hMAO-B inhibitor (R)-(−)-Deprenyl at 100 µM. Finally, molecular modelling studies revealed that compound 4 establishes key stabilizing interactions within hMAO-B, accounting for its high inhibitory potency and selectivity over hMAO-A. Full article

CD38 is a multifunctional enzyme that plays a pivotal role in NAD⁺ metabolism and calcium signaling, and its abnormal activity is closely associated with multiple myeloma, age-related metabolic decline, neurodegenerative diseases, and other disorders. Although monoclonal antibodies such as daratumumab have been approved for clinical application, their inherent limitations necessitate the development of novel small-molecule CD38 inhibitors. In this study, we employed DNA-encoded library (DEL) technology for the high-throughput screening of CD38 inhibitors, using a DEL library containing more than 100,000 unique compounds to screen against recombinant human CD38. A total of 1043 enriched compounds were initially identified, and after rigorous validation and screening to exclude non-specific binding and previously reported active compounds, eight hit compounds with diverse chemical scaffolds were obtained, among which Fenbendazole—a clinically approved antiparasitic drug—was included. Surface plasmon resonance (SPR) assays confirmed the direct binding of these hit compounds to CD38, with dissociation constants (KD) ranging from 7.74 × 10⁻⁵ M to 2.15 × 10⁻⁴ M. Fluorescence-based enzymatic activity assays demonstrated that these compounds exert dose-dependent inhibitory effects on both the hydrolase (with ε-NAD as substrate) and cyclase (with NGD as substrate) activities of CD38. Further structure–activity relationship (SAR) analysis of Fenbendazole analogues revealed the critical structural features that regulate CD38 inhibitory potency, and Flubendazole was found to exhibit excellent inhibitory activity, with an IC₅₀ of 14.78 ± 4.21 μM against CD38 hydrolase and 26.31 ± 3.40 μM against cyclase. Molecular docking and 100 ns molecular dynamics (MD) simulations further elucidated the molecular mechanism of CD38 inhibition by lead compounds, confirming that van der Waals interactions are the main driving force for the binding of small-molecule ligands to CD38, with conserved aromatic residues in the active site mediating ligand recognition. This study validates DEL technology as an efficient and reliable platform for the discovery of CD38 inhibitors, and the identified lead compounds—especially Fenbendazole and its analog Flubendazole—provide valuable molecular scaffolds for the further structural optimization of CD38 inhibitors. These findings lay a solid foundation for the development of novel therapeutic agents for the treatment of CD38-associated diseases. Full article

Background/Objectives: Thrombin, a serine protease central to coagulation and platelet activation, remains an important target for the development of safer and more effective antithrombotic agents. Naturally derived pentacyclic triterpenoids, such as betulinic acid and its acetylated derivatives, 3β-acetoxybetulinic acid, exhibit promising antiplatelet aggregation activity in validated in vitro and ex vivo assays; however, the molecular determinants underlying their direct thrombin inhibition remain unexplored. Results: Docking and MM/GBSA analyses revealed that Baa exhibits the strongest binding affinity (ΔG = −29.58 ± 2.97 kcal/mol), exceeding those of Ba (−20.94 ± 5.81 kcal/mol) and Asp (−18.87 ± 4.18 kcal/mol). Baa forms a highly persistent hydrogen bond with Trp96 (95.5% occupancy) and extensive hydrophobic contacts with Trp215, Leu99, Ile174, and Tyr60A residues defining thrombin’s aryl-binding pocket. MD trajectories demonstrated that Baa binding reduced solvent-accessible surface area (SASA) and residue fluctuations, indicating enhanced structural compaction and stability. In contrast, Ba exhibited weaker, transient hydrogen bonding, while Asp bound primarily near the catalytic triad. The triterpenes exhibit limited oral bioavailability, free PAINS alerts, favourable permeability and metabolic stability. Conclusions: Acetylation at C-3 (acetoxy substitution) substantially enhances thrombin binding via cooperative hydrogen bonding and van der Waals stabilisation, explaining the superior experimental inhibitory potency of Baa. These findings provide a mechanistic framework for structure-guided optimisation of triterpenoid-based thrombin inhibitors and support their further experimental development. Methods: In this study, molecular docking, molecular dynamics (MD) simulations (400 ns), and MM/GBSA free energy analyses were employed to elucidate the binding mechanisms of 3β-acetoxybetulinic acid (Baa), betulinic acid (Ba), and aspirin (Asp) within the thrombin receptor active site. The simulations were explicitly grounded in previously reported chromogenic antithrombin assays and platelet aggregation studies and were designed to mechanistically rationalise the experimentally observed inhibitory potency. Full article

Traditionally, Lasiocephalus ovatus Schltdl. (Asteraceae) has been used as an aromatic medicinal plant, particularly in the treatment of kidney-related ailments. However, scientific evidence validating its chemical composition and bioactivity remains limited. According to our literature search, there are no previous studies on the in vitro antibacterial, antioxidant, or anti-inflammatory activities of the essential oil from the aerial parts of Lasiocephalus ovatus; therefore, this study provides the first experimental evidence of these biological activities for this species. An essential oil (EO) was steam-distilled from the aerial parts of L. ovatus, grown at 4410 m above sea level in the paramos of Chimborazo Province (Ecuador), and subsequently analyzed. The distillation yield was 0.21% (w/w) based on dry plant material. Gas chromatography was employed for qualitative (GC-MS) and quantitative (GC-FID) analyses, using two different capillary columns, coated with 5% phenyl methyl polysiloxane (non-polar) and polyethylene glycol (polar) stationary phases. Dual stationary phases were required to provide complementary selectivity, which reinforced the identification and quantification of compounds. The major components of the EO were silphinene (3.4–3.5%), δ-selinene (3.6–3.1%), β-cyclogermacrene (18.7–18.1%), kessane (4.5–4.2%), spathulenol (13.3–13.3%), viridiflorol (3.1–3.0%) and neophytadiene (4.8–4.4%), values referred to the non-polar and polar phase respectively. The enantioselective analysis revealed that (1S,5S)-(−)-α-pinene, (1S,5S)-(+)-β-pinene and (R)-(−)-α-phellandrene were enantiomerically pure, whereas germacrene D was present as a scalemic mixture. The essential oil of L. ovatus exhibited a minimum inhibitory concentration (MIC) of 250 µg/mL against Staphylococcus aureus and 500 µg/mL against Escherichia coli. Its antibacterial activity is likely associated with the presence of bioactive sesquiterpenes such as silphinene, δ-selinene, and spathulenol, which are known for their membrane-disruptive properties. Regarding its antioxidant potential, the observed moderate radical scavenging activity (SC₅₀ = of 375.7 µg/mL) can be attributed to its complex mixture, particularly to oxygenated terpenoids like viridiflorol and spathulenol, which are recognized for their radical-neutralizing capacity. In the anti-inflammatory assay, the EO’s moderate potency (IC₅₀ = 165.29 ± 4.75 μg/mL) is also consistent with the anti-inflammatory profile reported for several of its major constituents, including spathulenol and viridiflorol. While significantly lower than that of aspirin (28.85 ± 7.66 μg/mL), this bioactivity is considerable within the context of a plant extract. Overall, the antibacterial, antioxidant, and anti-inflammatory effects are consistent with the EO’s terpene-rich composition, particularly oxygenated sesquiterpenes, while the enantiomeric distribution of chiral monoterpenes may further modulate bioactivity; consequently, future studies should include enantioselective quantification, broader antioxidant assays (e.g., ABTS, FRAP, ORAC, CUPRAC), cytotoxicity at active concentrations, and mechanistic and in vivo validation. Full article

To identify fungicide lead compounds with novel scaffolds and high efficacy, 33 novel bacillamide–acylhydrazone derivatives were successfully designed and synthesized by using a molecular hybridization strategy. The bioassay results showed that most of the target compounds exhibited promising inhibitory activity against B. cinerea. Among them, compound BAD-15 displayed the most potent antifungal activity with an EC₅₀ value of 6.725 μg/mL. Furthermore, preliminary SAR analysis revealed that the R group in hydrazine fragments exerts a significant influence on antifungal potency. Studying the molecular mechanism by morphological observation and transcriptome analyses revealed that BAD-15 may inhibit the activity of copper ion transmembrane transporters, leading to disrupted copper ion homeostasis and subsequent suppression of fungal growth. The present work indicates that bacillamide–acylhydrazone has potential as a novel scaffold for the development of fungicides, and compound BAD-15 may serve as a potential lead compound for the further development of novel fungicides. Full article

Voltage-gated potassium channel Kv1.3 plays an important role in the regulation of survival and apoptosis in many cell types, including both normal and cancer cells. Inhibitors of these channels may potentially find clinical applications in the treatment of various diseases, including certain cancers characterized by the over-expression of Kv1.3. In this study, the effects of isobavachalcone (IBC) and two non-prenylated chalcones—2′-hydroxy-4,3′-dimethoxychalcone (HDC) and 2′-hydroxy-2-methoxychalcone (HMC)—on Kv1.3 channel activity were investigated in the Jurkat T cancer cell line using the whole-cell patch-clamp technique. The electrophysiological measurements were preceded by experiments assessing cell viability, and the patch-clamp data were consistent with results obtained from MTT-based assays. We observed an almost complete and irreversible inhibition of Kv1.3 in the presence of IBC. The non-prenylated chalcones also inhibited the channels, but with lower potency and in a reversible and incomplete manner. The inhibitory effect of IBC was significantly enhanced upon co-application with simvastatin (SIM) and mevastatin (MEV). In contrast, inhibition by the non-prenylated chalcones was significantly increased only in the presence of mevastatin, but not simvastatin. The channel inhibition may be related to the anti-proliferative and pro-apoptotic activities of these compounds in Kv1.3-expressing cancer cells. Altogether, our results indicate that both prenylated and non-prenylated chalcones, particularly in combination with statins, may represent biologically active scaffolds, warranting further optimization and preclinical evaluation. Full article

Brazilian microalgae represent an underexplored reservoir of bioactive compounds with promising biotechnological and dermocosmetic applications. In this study, eight native Brazilian microalgae strains were cultivated under control (C) and stress conditions, nitrogen depletion (N) and salt stress (S), to modulate their bioactive profiles. Derived acetone extracts (24 samples) were evaluated for their antioxidant and antibacterial activities relevant to skin health. The antioxidant capacity of extracts was assessed by three complementary methods: ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picryl-hydrazyl (DPPH) and superoxide anion radicals scavenging. Additionally, the antibacterial effects against four skin microorganisms (Staphylococcus epidermidis, Staphylococcus hominis, Staphylococcus aureus, and Cutibacterium acnes) were also assessed. Among the tested samples, extracts from Scenedesmus armatus (Extract 40C) and from Chlorella sorokiniana (Extract 198C) displayed the highest antioxidant potential, with DPPH radical reduction of 22.6 ± 1.6% and 20.7 ± 1.9% and FRAP values of 178.3 and 156.8 μmol FeSO₄/g extract, respectively. Superoxide scavenging assays showed IC₅₀ values of 150.9 μg/mL for sample 40C and 139.6 μg/mL for sample 198C. Regarding the antibacterial assay, the IC₅₀ values for S. epidermidis were notable, with sample 198C exhibiting the highest potency (10.3 µg/mL), closely matching the standard drug (12.4 µg/mL). The inhibitory capacity against C. acnes showed that samples 40C (58.4 µg/mL) and 198C (83.5 µg/mL) demonstrated antimicrobial relevance. Mechanistic assays suggested that the antibacterial effects of both samples may involve alterations in bacterial membrane integrity and DNA damage. Overall, these findings highlight the dermocosmetic potential of native Brazilian microalgae, still largely untapped in biotechnology, as natural sources of multifunctional ingredients for the development of sustainable skin care formulations. Full article