Search Results (161)

Ubiquitin-specific protease 22 (USP22) regulates epigenetic gene expression by deubiquitinating histone H2B (H2Bub1) and upregulating oncogenic proteins and pathways, while antagonizing p53-mediated tumor suppression. USP22 is frequently overexpressed in cancers and associated with therapy resistance and poor prognosis yet remains largely untargeted pharmacologically. Here, using a fluorescence-based USP22 deubiquitinase assay to screen the LOPAC^®1280 library, we identified β-Lapachone, a natural ortho-naphthoquinone with strong anticancer activities, as a potent USP22 inhibitor. β-Lapachone potently inhibited USP22 enzymatic activity, with a half-maximal inhibitory concentration (IC₅₀) of ~0.75 μM, and molecular docking revealed its occupation of the catalytic pocket adjacent to the USP22 active-site triad, supporting a potential binding mode. Functionally, β-Lapachone suppressed proliferation and induced apoptosis in A549 and H1299 RAS-mutant lung adenocarcinoma (LUAD) cells, while USP22 knockout conferred marked resistance, indicating partial USP22 dependence. In patient-derived LUAD models, β-Lapachone inhibited sphere formation and reduced CD133⁺ cancer stem cell populations. Notably, it synergized with cisplatin to enhance DNA damage and apoptosis. In vivo, β-Lapachone significantly suppressed tumor growth in a syngeneic KRAS-mutant/p53-Null mouse lung cancer model and further potentiated cisplatin-induced antitumor effects. Collectively, these findings identify β-Lapachone as a potent inhibitor of USP22 and validate USP22 inhibition as a key mechanism underlying its anticancer activity in LUAD cells, both in vitro and in vivo. Full article

Psoriasis is a chronic, immune-mediated inflammatory skin disease for which the development of structurally novel and accessible small-molecule candidates remains of considerable interest. In this study, a series of juglone-derived naphthoquinone analogs was synthesized to explore the influence of substitution pattern on anti-inflammatory activity and cytotoxicity. Their biological profiles were first evaluated in LPS-stimulated HaCaT cells by combining cytotoxicity assessment with nitric oxide (NO) screening. Most derivatives showed reduced cytotoxicity compared with juglone, and preliminary structure–activity relationship analysis indicated that retention of a free hydroxyl group at the C-2 position was generally favorable for both reduction in NO release and cellular safety, whereas C-3 alkyl substitution tended to weaken activity and increase cytotoxicity. Among the tested compounds, compound 11 showed the most favorable balance between reduction in NO release and low cytotoxicity. Further evaluation showed that compound 11 reduced the protein levels of several inflammatory mediators in the culture supernatants of LPS-stimulated HaCaT cells, including TNF-α, IL-6, IL-1β, IL-17A, and IL-23, under the tested conditions. In an imiquimod-induced psoriasis-like mouse model, topical administration of compound 11 partially alleviated IMQ-induced psoriasis-like skin lesions, improved histopathological changes to some extent, and reduced selected inflammatory cytokine levels in serum and skin tissues under the tested conditions. Exploratory target prediction, molecular docking, and in silico ADMET analyses provided supportive computational insight into the biological profile of compound 11. Overall, these findings suggest that juglone-derived naphthoquinones may serve as useful natural-product-inspired scaffolds for further anti-inflammatory optimization, and compound 11 warrants further investigation in psoriasis-related experimental models. Full article

Background: Shikonins are natural naphthoquinones that exhibit a range of biological activities. They are typically extracted using nonpolar solvents; however, green extraction approaches remain underexplored. Methods: Phytochemical profiling of E. vulgare root extracts was performed using HPLC-ESI-QTOF-MS/MS and quantitative analysis using HPLC-PDA. Shikonin extraction was performed using VNADESs based on thymol, camphor, menthol and benzyl alcohol. The feasibility of removing the VNADES from the extracts via freeze-drying was assessed. The cytotoxic, antioxidant, anti-inflammatory and antimicrobial activities of the hexane extract and the selected VNADES-based extract (TBa 2:8) were compared. Results: Eight shikonin derivatives were identified in the extracts. VNADES extracts contained comparable amounts of shikonin to hexane extracts; however, freeze-drying resulted in significant shikonin content loss. TBa 2:8 extract exhibited noticeably lower cytotoxicity than the hexane extract while its antioxidant potential depended on the assay applied. In contrast to the hexane extract, TBa 2:8 demonstrated the ability to reduce intracellular ROS and NO levels. However, the hexane extract exhibited stronger antimicrobial activity. Conclusions: VNADES systems enable efficient extraction of shikonin derivatives with performance comparable to hexane. Although the resulting extracts exhibit multidirectional biological activity, it remains challenging to remove the VNADESs effectively without losing the shikonins. Full article

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies, highlighting the need to identify novel bioactive compounds with antitumor potential. Natural products constitute a valuable source of molecules with anticancer activity. In this study, we performed a comparative analysis of two classes of natural compounds—sesquiterpene lactones (achillin and polymatin A) and naphthoquinones (α, β-lapachone and lapachol)—in human PDAC cell lines on cell proliferation, metabolic activity and cell death induction and early mitochondrial alterations. Achillin showed limited antiproliferative, metabolic, and cytotoxic activity, whereas polymatin A exhibited activity in the micromolar range, yielding LC₅₀ values of 16.11 ± 2.27 μM and 20.00 ± 1.90 μM for PANC-1 and MIAPaCa-2 cells, respectively. The naphtoquinones α- and β-lapachone effectively inhibited proliferation and metabolic activity and triggered cell death in both PDAC cell lines, with β-lapachone consistently displaying the highest activity with an LC₅₀ of 4.00 ± 0.07 μM for PANC-1 cells and 3.89 ± 0.50 μM for MIAPaCa-2. Interestingly, achillin, polymatin A, α- and β-lapachone selectively induced cell death while sparing PBMCs. In contrast, lapachol showed weak activity, failing to achieve 50% inhibition or cell death within the tested concentration range and lacking tumor selectivity. Mechanistically, quinone derivatives promoted early mitochondrial superoxide modulation and membrane depolarization, consistent with a redox-active profile, whereas sesquiterpene lactones induced mitochondrial depolarization with limited mitochondrial superoxide overproduction, suggesting a distinct bioenergetic disruption phenotype. Overall, these findings highlight structure–activity relationships among natural compounds and support further investigation of achillin, polymatin A and α,β-lapachone as promising molecular scaffolds in PDAC research. Full article

The therapeutic efficacy of antibiotics has been significant in extending human life expectancy by combating virulent bacterial infections. Nevertheless, multidrug-resistant (MDR) microorganisms remain a global crisis as these bacteria have developed resistance to conventional antibacterial agents. An unexplored antibiotic target found exclusively in bacteria is the Na⁺-translocating NADH:ubiquinone oxidoreductase (NQR), which is an indispensable membrane-bound bacterial enzyme complex that enables cellular functionality and is present in many infectious bacterial species, including Vibrio cholerae and H. influenzae. NQR serves as an essential complex in the bacterial electron transport chain (ETC) and operates as a highly conserved primary Na⁺ pump that drives many bioenergetic functions. This six-subunit protein shuttles electrons from NADH to ubiquinone, which drives the translocation of Na⁺ ions and creates a gradient that provides the driving force for various cellular processes. We have synthesized and evaluated a series of 1,4-naphthoquinones that exhibit high potency against NQR with minimal cytotoxicity and potential to serve as new, NQR-targeting antibacterial agents for use against V. cholerae. Full article

Chagas disease is caused by the protozoan Trypanosoma cruzi, and its current treatment is limited to the use of two nitroderivatives, benznidazole (Bz) and nifurtimox; however, their toxicity often leads to discontinuation, justifying the search for new therapeutic options. The biological activity of quinones has long shown efficacy towards pathogenic microorganisms. In our previous investigations, two naphthoquinones combining ortho- and para-quinoidal moieties exhibited remarkable trypanocidal activity and presented low toxicity to host cells. Here, these two active compounds were further assessed. On trypomastigotes and epimastigotes, brominated (NQ1) and chlorinated (NQ2) nor-beta-lapachone-derived 1,2,3-triazoles were more active than Bz, presenting IC₅₀/24 h values in the range of 0.8 to 3.1 µM. NQ1-treated epimastigotes showed a mitochondrial impairment and reactive oxygen species (ROS) production under electron microscopy and flow cytometry. The in vitro evaluation of both combinations of compounds with Bz indicated an additive interaction. In vivo, oral treatment with NQ1 reduced parasitemia in an acute model, with no evidence of toxicity. The treatment also led to a reduction in myocarditis, decreasing the PR interval in electrocardiographic analysis and reversing the sinus bradycardia caused by infection. These data suggest that T. cruzi mitochondrion are part of the NQ1 mechanism of action. In vivo, this compound presented moderate trypanocidal and promising anti-inflammatory activity. Its combination with Bz could enhance current therapeutic protocols and should be better explored in the future. Full article

Background/Objectives: β-Lapachone and triapine are compounds with recognized antitumor potential—the former is an ortho-naphthoquinone, and the latter a thiosemicarbazone inhibitor of ribonucleotide reductase. This study aimed to synthesize and evaluate new β-lapachone-based thiosemicarbazones (TSC1–TSC6) as potential antineoplastic agents. Methods: Lapachol was isolated from Tabebuia sp. and used to obtain ortho-naphthoquinones (2–4), which served as precursors for thiosemicarbazones (TSC1–TSC6). NMR and HRMS spectra were used to characterize the compounds. Their cytotoxic activity was evaluated in vitro against murine melanoma (B16–F10), colon carcinoma (CT26.WT), and breast cancer (4T1) cell lines, as well as normal fibroblasts (L929). Pharmacokinetic parameters were predicted in silico using ADMETLab 3.0. Results: β-Lapachone exhibited strong cytotoxicity toward tumor cells with moderate effects on normal cells, while thiosemicarbazones of β-lapachone, TSC1, and TSC3 demonstrated lower potency but greater selectivity. The β-lapachone-3-sulfonic acid showed high activity against melanoma and breast cancer cells and low toxicity toward normal cells, indicating tumor selectivity. In contrast, their thiosemicarbazones, TSC2, TSC4, and TSC6, showed weak or no antiproliferative activity. The 3-iodo-β-lapachone was cytotoxic to both tumor and normal cells, whereas its derivative TSC5 demonstrated moderate activity with reduced toxicity. β-Lapachone, β-lapachone-3-sulfonic acid, TSC1, and TSC3 exhibited favorable ADME profiles (QED ≈ 0.61–0.66), suggesting good oral bioavailability. Conclusions: The β-lapachone-3-sulfonic acid and the β-lapachone-based thiosemicarbazones TSC1 and TSC3 emerged as promising lead candidates, combining tumor selectivity, favorable pharmacokinetic properties, and structural innovation for the development of safer and more effective antineoplastic agents. Full article

Background: The reintroduction of colistin has led to the rapid emergence of colistin-resistant strains, significantly diminishing its therapeutic efficacy. This presents a need for effective adjuvants to restore colistin efficacy. Approach: We screened the colistin adjuvants through a high-throughput method and then evaluated their synergistic effects and underlying mechanisms. Results: We identified β,β-dimethylacrylalkannin (β,β-Dim), a naphthoquinone compound derived from Lithospermum erythrorhizon, as a potent colistin adjuvant (fractional inhibitory concentration index (FICI) < 0.5). β,β-Dim enhanced colistin activity against 4 of 6 susceptible strains and all 18 colistin-resistant strains carrying either plasmid-borne mcr genes (mcr-1, mcr-3, mcr-8, and mcr-9) or chromosomal two-component system (TCS) mutations (pmrA/B, phoP, and mgrB). These strains included Klebsiella pneumoniae, Escherichia coli, Salmonella Typhimurium, Pseudomonas aeruginosa, and Acinetobacter baumannii. The combination reduced the minimum inhibitory concentrations (MICs) of colistin by 4–1024-fold (from 512 to ≤2 µg/mL). Mechanistically, colistin-mediated outer membrane permeabilization facilitates β,β-Dim entry. Once internalized, β,β-Dim interacts with cytoplasmic membrane phospholipids and disrupts membrane biofunction. Further analysis showed that LPS transport and efflux pump activity were impaired, leading to LPS accumulation in the cytoplasmic membrane and increased intracellular colistin content. These processes elevated reactive oxygen species (ROS) production and markedly reduced ATP levels. In a murine infection model, β,β-Dim (2 mg/kg) combined with colistin (0.2 mg/kg) markedly increased survival from 20% (colistin alone) to 80%. Conclusions: These findings highlight that β,β-Dim combined with colistin is a promising therapeutic strategy for infections caused by colistin-resistant pathogens. Full article

Background: Tuberculosis (TB) remains a critical global health concern, exacerbated by the emergence of multidrug-resistant and extensively drug-resistant strains of Mycobacterium tuberculosis. In the search for novel therapeutic agents, naphthoquinones have garnered interest due to their diverse mechanisms of action and potent antimycobacterial activity. In this study, we report the design, synthesis, and biological evaluation of a novel series of eleven naphthoquinone-based derivatives (compounds 22–32), developed through a molecular hybridization strategy targeting shikimate kinase (Mtb-SK) an essential enzyme present exclusively in M. tuberculosis. Methods: The compounds were synthesized via a straightforward and efficient synthetic route, and preliminary screening identified five molecules with significant anti-TB activity. Notably, compound 26, 4-(4-ethoxyphenyl) amino) Naphthalene-1,2-dione, exhibited a minimum inhibitory concentration (MIC) of 21.33 µM, comparable to ethambutol and substantially more potent than pyrazinamide. Results: Molecular docking studies indicated that all active compounds interact favorably within the shikimate binding pocket of Mtb-SK, following the proposed mechanism of action. Additionally, ongoing cytotoxicity assays in HepG2 cells aim to assess the selectivity of these derivatives. Conclusions: These findings support the potential of this new class of naphthoquinones as promising scaffolds for the development of anti-TB agents, contributing to the growing body of research focused on new chemotherapeutic options against tuberculosis. Full article

Cancer remains one of the leading causes of morbidity and mortality worldwide, demanding the continuous search for novel and more selective chemotherapeutic agents. Quinones, particularly naphthoquinones, constitute a privileged class of redox-active compounds with well-documented antitumor activity. Likewise, thiazoles represent a heterocyclic scaffold widely explored in medicinal chemistry due to their broad pharmacophoric adaptability and diverse biological activities. In this context, this review comprehensively explores the chemical synthesis and anticancer potential of hybrid molecules combining the naphthoquinone and thiazole scaffolds. The hybridization of these pharmacophores has emerged as a powerful strategy to design multitarget antitumor agents. The review summarizes key synthetic methodologies, including Hantzsch, hetero Diels–Alder cycloaddition and multicomponent reactions, leading to structurally diverse hybrids. Particular emphasis is placed on derivatives exhibiting strong cytotoxic effects against a broad spectrum of cancer cell lines (e.g., OVCAR3, MCF-7, A549, HCT-116, HeLa, and Jurkat), low toxicity toward normal cells and well-defined mechanisms of action involving topoisomerase IIα, EGFR, STAT3, and CDK1 inhibition, as well as ROS generation and cell cycle arrest. Among these, certain hybrids displayed nanomolar potency and high selectivity indices, reinforcing their potential as promising lead compounds for anticancer drug development. Full article

The naphthoquinone juglone (5-hydroxynaphthalene-1,4-dione) (1) occurs abundantly in nature, especially in species belonging to the Juglandaceae family. Due to its multifaceted biological activities, this compound is considered a privileged structure in Medicinal Chemistry for the development of new prototypes with several biological and pharmacological actions. However, the regioselective synthesis of 2-substituted juglones is challenging due to the non-symmetric naphthoquinone nucleus. Starting from non-symmetric 2,3-unsubstituted naphthalenes, in this paper we describe two general synthetic routes to juglone derivatives bearing an unsaturated or an oxygenated aliphatic side chain at C(2) or C(3). In an MTT test, a few products were more active than the parent unsubstituted juglone as inhibitors of the viability of human lung cancer H460 and breast cancer MCF-7 cells. The most potent compound featured a 1′-acetoxyhomoprenyl sidechain at the carbon C(2) of juglone. Full article

The reaction of a 2-naphthol-derived Mannich base with the push-pull 5-morpholinopenta-2,4-dienal under acidic conditions unexpectedly afforded (7aR*,7bR*)-7a,7b-dihydro-15H-dibenzo[f,f′]cyclopenta[1,2-b:5,4-b′]dichromene. The structure of this product was unambiguously confirmed by NMR spectroscopy and X-ray diffraction analysis. A plausible mechanism involves the in situ generation of 1,2-naphthoquinone-1-methide, followed by a [4 + 2] cycloaddition and a subsequent interrupted iso-Nazarov cyclization. In this process, the enol tautomer of the resulting fused cyclopentenone is trapped by a second equivalent of the 1,2-naphthoquinone-1-methide, leading to the observed polycyclic framework. Full article

The naphthoquinone skeleton is known for broad biological applications and, in particular, for antiparasitic efficacy. As part of our ongoing search for new antiprotozoal naphthoquinone derivatives, we incorporated computer-aided optimization models utilizing physicochemical parameters into our approach. Herein, we report on the synthesis of 21 new benzamido–menadione and naphthoquinone derivatives via the Kochi–Anderson reaction. The antiprotozoal activity of all the synthesized compounds was evaluated against Plasmodium falciparum NF54 and Trypanosoma brucei rhodesiense STIB900. Cytotoxicity towards L6 cells was also determined, and the respective selectivity indices (SI) were calculated. Several ligand efficiency metrics, such as LLE, SILE, and FQ, were calculated, and the results were visualized in scatterplots. Almost all of the synthesized benzamido–menadione derivatives exhibited high activity against NF54 (IC₅₀ < 1 µM), with the strongest activity and excellent selectivity observed in the 2-fluoro-5-trifluoromethylbenzamido derivative 2f (IC₅₀ = 0.021 µM, SI = 10,000). Specific ligand efficiency metrics, such as SILE, LLE or FQ, showed a clear correlation with the corresponding antiplasmodial activities. Toxicity predictions confirmed low acute oral toxicity for most compounds, further supporting their potential as safe drug candidates. Our findings highlight the benzamido–menadione scaffold as a viable option for new antiplasmodial drugs. Full article

This study aimed to determine the antifungal activity of various compounds and develop a novel antifungal formulation against fungal pathogens, including Alternaria alternata, Botrytis cinerea, Penicillium expansum, and Rhizopus stolonifer. A total of 32 plant-derived secondary metabolites and three extracts (dichloromethane, ethyl acetate, and methanol) from Lawsonia inermis, Juglans regia, and Drosera intermedia were screened at a concentration of 250 ppm. The chemical composition of the D. intermedia ethyl acetate extract was characterized using chromatographic techniques. Subsequently, an emulsifiable concentrate formulation from this extract was prepared, and its efficacy was evaluated at concentrations ranging from 250 to 2000 ppm. The D. intermedia ethyl acetate extract was found to contain three flavonoids (1.4%) and three naphthoquinones (2.8%). The formulation exhibited optimal effect at 1000 ppm. Overall, the high efficacy of the formulation containing the dried D. intermedia extract (10:1, ethyl acetate) positions it as a promising and viable alternative to synthetic fungicides. Full article

Background/Objectives: Ferroptosis, an iron-dependent form of regulated cell death characterized by excessive lipid peroxidation, has been implicated in various acute and chronic brain disorders, including epilepsy. Although 1,4-naphthoquinone derivatives have been reported to regulate ferroptosis, their mechanistic roles in the nervous system remain underexplored. Here, we investigated the protective effects of 8-hydroxy-2-anilino-1,4-naphthoquinone (8-HANQ) on ferroptotic neuronal death in vitro and seizure behaviors in vivo. Methods: HT22 hippocampal cells were exposed to ferroptosis inducers including glutamate, glutamate plus iron, or RSL3. Lipid reactive oxygen species (ROS), ferroptosis markers, and its related molecules were assessed by flow cytometry and Western blotting. In a kainate (KA)-induced seizure model, 8-HANQ was delivered intracerebroventricularly, followed by behavioral seizure scoring and analysis of hippocampal levels of PSD95, cathepsin-B, and FGFR1 at 72 h post-seizure. Results: 8-HANQ attenuated ferroptotic death in HT22 cells, reducing lipid ROS accumulation and abnormal acyl-coA synthetase long chain family member 4 (ACSL4), suggesting 8-HANQ’s anti-ferroptotic action. Moreover, 8-HANQ also prevented aberrant STAT3-dependent cathepsin-B overexpression while modulating soluble N-cadherin-mediated FGFR1 activation. In vivo, 8-HANQ decreased KA-induced seizure behavior, restored hippocampal cathepsin-B and PSD95 expression, and partially alleviated dysregulation of FGFR1 activation. Conclusions: 8-HANQ prevents ferroptotic neuronal death and synaptic deficits involving FGFR1/STAT3/cathepsin-B-driven ferroptosis while lowering seizure severity, suggesting that 8-HANQ may serve as a potential anti-ferroptotic and anti-seizure agent. Full article