Naphthoquinone Analogues Research Articles

Combinatorial screening for therapeutics in ATTRv amyloidosis identifies naphthoquinone analogues as TTR-selective amyloid disruptors

Hereditary ATTR amyloidosis is caused by the point mutation in serum protein transthyretin (TTR) that destabilizes its tetrameric structure to dissociate into monomer. The monomers form amyloid fibrils, which are deposited in peripheral nerves and organs, resulting in dysfunction. Therefore, a drug that dissolves amyloid after it has formed, termed amyloid disruptor, is needed as a new therapeutic drug. Here, we first established a high throughput screening system to find TTR interactors from the LOPAC1280 compound library. Among the hit compounds, thioflavin T-based post-treatment assay determined lead compounds for TTR amyloid disruptors, NSC95397 and Gossypol, designated as B and R, respectively. Because these compounds have naphthoquinone-naphthalene structures, we tested 100 naphthoquinone derivatives, and found 10 candidate compounds that disrupted TTR amyloid. Furthermore, to determine whether these 10 compounds are selective for TTR amyloid, we evaluated them against beta-amyloid (Aβ1-42). We found two compounds that were selective for TTR and did not disrupt Aβ-derived amyloid. Therefore, we succeeded in identifying TTR-selective amyloid disruptors, and demonstrated that naphthoquinone compounds are useful structures as amyloid disruptors. These findings contribute to the on-going efforts to discover new therapeutic tools for TTR amyloidosis.

Abstract 1862: Naphthoquinone analogues inhibit Wnt/β-catenin signaling and colorectal cancer tumorigenesis

Abstract In this study, we performed a structure-activity-relationship study of seven previously identified chloro-naphthoquinone analogs and evaluated their abilities to inhibit the Wnt/β-catenin signaling pathway. The Wnt/β-catenin signaling pathway plays essential roles in colorectal cancer (CRC) initiation, proliferation, and development. While targeting the Wnt/β-catenin pathway has been validated as a very promising approach for CRC treatment, developing a therapeutic for inhibition of this elusive pathway has been very challenging for researchers. Of the seven chloro-naphthoquinone analogues, we found that two compounds, Compound 3 and Compound 6, significantly inhibited Wnt target gene transcription and Wnt-induced colorectal tumorigenesis in vitro. Chromatin immunoprecipitation binding assays and computational modeling analysis revealed that Compound 3 and Compound 6 inhibit the Wnt/β-catenin pathway through disruption of the TCF4-DNA binding, a crucial step for the activation of the Wnt/β-catenin signaling pathway. Lastly, using a patient-derived organoid model and xenograft mouse model, we showed that these compounds inhibit CRC tumorigenesis. Taken together, this study demonstrates a novel mechanism of action for these chloro-naphthoquinone analogs, which can be further explored in future drug design and discovery efforts for small molecules targeting the TCF family proteins for inhibition of the Wnt/β-catenin signaling pathway. Citation Format: Rosalie G. Hoyle, Andrew Morris, Piyusha Pagare, Shadid Uz Zaman, Zhikun Ma, Yan Zhang, Jiong Li. Naphthoquinone analogues inhibit Wnt/β-catenin signaling and colorectal cancer tumorigenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1862.

Exploration of naphthoquinone analogs in targeting the TCF-DNA interaction to inhibit the Wnt/β-catenin signaling pathway

The Wnt/β-catenin signaling pathway plays extensive roles in cancer initiation, proliferation, and development, and has been implicated in the regulation of stem cells in the intestinal crypt, widely accepted as responsible for colorectal cancer (CRC) origination. This pathway has been a target of interest for many years for chemotherapeutic development of CRC due to its implication in most cases. Previously, a series of naphthoquinone analogs have been identified to inhibit the Wnt/β-catenin. It was postulated that these compounds exhibit their inhibitory activity via binding to β-catenin at the β-catenin/TCF4 interaction interface. In this study, we aimed to further define the critical pharmacophore for these compounds and verify their mechanisms of action for their abilities to inhibit the Wnt/β-catenin signaling pathway. Interestingly, our data suggested two of the compounds, compounds 3 and 6, may potently inhibit the Wnt/β-catenin signaling pathway via inhibition of the TCF4/DNA interaction, a novel finding compared to previous studies on these compounds. Our computational studies suggested that the compounds bound within the DNA binding HMG-box domain of TCF4 to elicit their inhibitory action. These compounds inhibited Wnt signaling in a dose dependent manner, suppressed Wnt direct target genes and demonstrated unforeseen degradation of the TCF4 protein. Thus, this study revealed a potentially novel mechanism of action of the chloro-naphthoquinone as possibly a multi-targeting scaffold, which warrants further investigation in future drug discovery on the ‘undruggable” TCF proteins and an aberrantly activated Wnt/β-catenin signaling pathway.

An Update on the Synthesis and Applications of Bis(Naphthoquinones): An Important Class of Molecules against Infectious Diseases and other Conditions.

Naphthoquinones are important molecules belonging to the general class of quinones, and many of these compounds have become drugs that are in the pharmaceutical market for the treatment of several diseases. A special subclass of compounds is that of the bis(naphthoquinones), which have two linked naphthoquinone units. In the last few years, several synthetic approaches toward such valuable compounds have been described, as well as their evaluation against numerous important biological targets. In this review, we provide a thorough discussion on the various synthetic methods reported for the synthesis of bis(naphthoquinone) analogues, also highlighting the biological activities of these substances.

Combinatorial Cytotoxic Effects of 2,3-Dichloro-5,8-dimethoxy-1,4-naphthoquinone and 4-hydroxytamoxifen in Triple-negative Breast Cancer Cell Lines.

Triple-negative breast cancer (TNBC) is a highly aggressive form of breast cancer (BC) and lacks targeted therapy and alternate therapeutic combinations. There is a necessity to increase disease-free survival in patients particularly within the first 5 years of diagnosis. 2,3-dichloro-5,8-dimethoxy-1,4-naphthoquinone (Z285), a novel 1,4 naphthoquinone analog, has been shown to have cytotoxic activity in BC cell lines and in combination with 4-hydroxytamoxifen (4-OHT). A known metabolite of tamoxifen, was postulated to decrease cell proliferation. Thus, this study investigates the use of Z285 and 4-OHT alone or in combination as a novel therapeutic alternative for TNBC. Cell proliferation assays were performed on MDA-MB-231, Hs578T, MCF7 and HCC1806 cell lines at varying time points with Z285 and 4-OHT alone and in combination. Furthermore, ROS activity was measured to determine the changes in oxidative stress caused by both drugs. The results showed dose- and time-dependent decreases in proliferation for all cell lines when treated with Z285, 4-OHT and their combination. Combinatorial analysis performed at 72 h using Synergyfinder® showed additive effects in MCF7, HCC1806 and Hs578T and an antagonistic response in MDA-MB-231. Z285 caused a significant increase in ROS production in three cell lines after 8 h, but HCC1806 showed no change in effect. These promising results suggest the independent ability of each compound as a stand-alone chemotherapeutic agent, or in combinatorial therapy for the treatment of TNBC.

Vitamin K3 thio-derivative: a novel specific apoptotic inducer in the doxorubicin-sensitive and -resistant cancer cells.

Vitamin K3, also known as menadione, is a synthetic lipid-soluble 2-methyl-1,4- naphthoquinone analogs of vitamin K. The vitamin K derivatives exhibit potent cytotoxicity against several cancer cell lines through ROS induction and mitochondrial dysfunction. We investigated vitamin K3-inspired derivatives as potential apoptotic inducers and analyzed their mechanisms beyond apoptosis. The cytotoxicity of a panel of vitamin K3 analogs was screened against 10 doxorubicin-sensitive and -resistant cancer cell lines overexpressing ATP-binding cassette transporters (P-glycoprotein, ABCB5, BCRP) or oncogenes (ΔEGFR) or with knockout of tumor suppressors (p53), Cell cycle arrest, apoptosis, cell migration, and microtubule formation were further investigated. The online tool SwissTargetPrediction was utilized for target prediction. Among the screened compounds, one vitamin K3 thio-derivative (No. 45, VKT-1) exhibited the most potent cytotoxicity specifically against both drug-sensitive and -resistant cancer cell lines. In addition, VKT-1 arrested the cells at the G2/M phase and induced apoptosis as detected by flow cytometry. As predicted by SwissTargetPrediction, VKT-1 targeted microtubule-associated tau protein. Indeed, VKT-1 dramatically inhibited cell migration and microtubule formation in vitro. In conclusion, the synthetic vitamin K3 thio-derivative (VKT-1) inhibited doxorubicin-sensitive and -resistant tumor cells by cell arrest, apoptosis induction, as well as, migration inhibition, and microtubule deterioration of U2OS-GFP-α-tubulin cells.

Structure-activity relationship studies on naphthoquinone analogs. The search for new herbicides based on natural products.

Allelopathy and bioassays constitute fundamental tools in the search for new herbicide templates. The work described here is a continuation of a previous study focused on the structure-activity relationships between transport phenomena and phytotoxic activity. Different modifications were made to the naphthoquinone backbone and two key factors were identified as being responsible for changes in activity: lipophilicity and the nature of the functional group. The study of other naturally occurring and semi-synthetic naphthoquinones was also proposed. A total of 12 5-O-acyl plumbagins and 18 analogs with unsaturated and aromatic substituents at positions 2 and 5 were synthesized. These compounds were evaluated in the wheat coleoptile bioassay and against Standard Target Species (STS) and three weeds, namely Echinochloa crus-galli L., Lolium rigidum Gaud. and Lolium perenne L. A strong structure-function relationship was observed for the different naphthoquinones and root and shoot length were the parameters that were most affected. Strong inhibitory effects were observed for the isomeric forms 23 and 33 and the derivatives with a free hydroxyl group, i.e. 24 and 30, gave values higher than 70% inhibition for root length in barnyardgrass and perennial ryegrass. These results highlight the potential of these compounds as models in the development of herbicides based on natural products. © 2019 Society of Chemical Industry.

Antiproliferative and proapoptotic activities of aza-annulated naphthoquinone analogs

1,4-Naphthoquinone derivatives have been widely documented with regard to their biological properties, and particularly their anticancer activities. In the 9,10-anthraquinone family, aza-annulation involving one of the carbonyl oxygen atoms has afforded more potent, possibly less toxic analogues. We recently carried out different modifications on the naphthoquinone skeleton to generate 3-chloro-2-amino- and 3-chloro-2-(N-acetamido)-1,4-naphthoquinone and 3,4-dihydrobenzo[f]quinoxalin-6(2H)-one derivatives. These three series of compounds were now tested against normal human fibroblasts and six human cancer cell lines. Some of the dihydrobenzoquinoxalinone derivatives were not only more potent than their 1,4-naphthoquinone counterparts, but also exhibited 10- to 14-fold selectivity between bladder carcinoma and normal cells and were equipotent with the non-selective reference drug used (etoposide). The fusion of an additional azaheterocycle to the 1,4-naphthoquinone nucleus modulates both the activity, selectivity and mechanism of action of the compounds. The electrochemical properties of selected compounds were evaluated in an attempt to correlate them with cytotoxic activity and mechanism of action. Finally, 3D-QSAR CoMFA and CoMSIA models were built on the AGS, J82, and HL-60 cell lines. The best models had values of r2pred = 0.815; 0.823 and 0.925. The main structural relationships found, suggest that acetylation and alkylation of the amino group with large groups would be beneficial for cytotoxic activity.

Virtual screening of naphthoquinone analogs for potent inhibitors against the cancer-signaling PI3K/AKT/mTOR pathway.

The PI3K/AKT/mTOR pathway is one of the most commonly disrupted signaling pathways that plays a role in the development and pathogenicity of multiple cancers. Therefore, the critical proteins of this pathway have been targeted for anticancer therapy. The scientific community has increasingly been realizing the anti-cancer therapeutic potential of naphthoquinone analogs. These compounds constitute a major class of diverse sets of plant metabolites, which include various natural products and synthetic compounds with proven anticancer activity. The current study involved structural computational biology approaches to explore compounds from a diverse pool of naphthoquinone analogs that can inhibit key cancer-signaling proteins phosphoinositide 3-kinase (PI3K), protein kinase B, PKB (AKT), and mammalian target of rapamycin (mTOR). The novel compound identified commonly among the top 10 dock score lists of PI3K, AKT, and mTOR was selected for further study and proposed as a potential inhibitor of the 3 cancer-signaling proteins and an anticancer agent. Further, to check the docking accuracy and potential of the compound, post docking analyses, namely, binding comparison with the native ligand, the role of the interacting residue role in binding, predicted binding energy and dissociation constant calculations, etc., were performed. All these measures showed good-quality binding, and thus provide weight to our prediction of the novel compound as a pan PI3K/AKT/mTOR inhibitor and an anticancer agent. Finally, to compare the binding and similarity in the active sites of the 3 protein kinases, a ligand-based active site alignment was performed and analyzed. Thus, the study proposed a novel naphthoquinone analog as a potential anticancer drug, and provided comparative structural insight into its binding to the 3 protein kinases.

A new naphthoquinone analogue and antiviral constituents from the root of Rhinacanthus nasutus

Rhinacanthus nasutus (L.) Kurz (Acanthaceae) is known as traditional medicine for the treatment of fungal and herpes virus infections. A new naphthoquinone racemate, rhinacasutone (1) together with seven known compounds, rhinacanthone (2), rhinacanthins C, D, N, Q, and E (3–7), and heliobuphthalmin (8) were isolated from root of R. nasutus. Their structures were determined on the basis of extensive spectroscopic methods, including 1D-, 2D-NMR and MS data. All the isolated compounds were tested for their antiviral activities against PR8, HRV1B, and CVB3-infected vero cells. Compounds 3–6 exhibited significant antiviral activities with the IC50 value ranging from 0.03 to 23.7 μM in all three infections.

Inhibition of Polymorphic Property of Naphthoquinonepigment Derived from Vitamin K.

Organicpigment, 2-Methyl-3-(4-fluorophenylthio)-1,4-naphthalenedione (2), that is a new Vitamin K derivative bearing a fluorine group, did not show any polymorphism disregard of three different solvents. For comparison, its naphthoquinone analogue with a bromine group (1) showed clearly polymorphism susceptible to these solvents.

Naphthoquinone Derivatives As Low-Potential Electron Mediators of Fad-Dependent Glucose Dehydrogenase

Flavin adenine dinucleotide-dependent glucose dehydrogenase (FAD-GDH) is rapidly emerging as an alternative glucose-oxidizing enzyme in enzymatic fuel cells (EFCs). FAD-GDH has the benefit over its commonly used counterpart, glucose oxidase (GOx), of not undergoing the parasitic reduction of O2 to H2O2, which can be troublesome in EFC applications. Additionally, the FAD cofactor has a relatively low redox potential in comparison to heme-based and PQQ-dependent enzymes, which can allow for a much higher theoretical cell potential. However, FAD-GDH is unable to facilitate rapid rates of direct electron transfer, and therefore requires a low-overpotential redox mediator to take full advantage of the low oxidation potential of its FAD cofactor. We have prepared a range of naphthoquinone analogues that are capable of mediating electron transfer between FAD-GDH and carbon electrodes, with onset potentials ranging between -0.425 to -0.150 V (vs. SCE), at pH 7.4. Several naphthoquinone derivatives were immobilized either onto a poly(ethylenimine) backbone or directly onto the outer shell of FAD-GDH to yield a naphthoquinone redox hydrogel and a naphthoquinone-labeled FAD-GDH. Both methods demonstrated large catalytic current densities at low onset potentials. When coupled with an O2-reducing biocathode (bilirubin oxidase, direct electron transfer-type) the glucose/O2 EFC possessed a large open-circuit potential (OCP) of 0.864 V and was able to deliver a maximum current density of 5.4 mA cm-2. The EFC reached its maximum power density (2.3 mW cm-2) at 0.55 V.

Acequinocyl resistance in Tetranychus urticae Koch (Acari: Tetranychidae): inheritance, synergists, cross-resistance and biochemical resistance mechanisms

Acequinocyl is the only commercialized acaricide of the naphthoquinone analogue group. To develop strategies to minimize resistance, a laboratory-selected acequinocyl-resistant strain of the two-spotted spider mite Tetranychus urticae was used to determine the inheritance, toxicological, biochemical and cross-resistance data. The LC50 and LC60 values of acequinocyl were determined on T. urticae using a leaf-disc method and spraying tower. A laboratory selection population designated ACE6 had a122.0-fold resistance to acequinocyl following six selection cycles. A selected strain showing 112.0-fold resistance was named ACE6 population. This population developed low resistance to etoxazole and spirodiclofen and moderate cross-resistance to hexythiazox, milbemectin and bifenazate. Monooxygenase enzyme inhibitor piperonyl butoxide, the esterase enzyme inhibitor S-benzyl O,O-diisopropyl phosphorothioate and the glutathione S-transferase (GST) enzyme inhibitor diethyl maleate synergized resistance values were 1.0-, 2.5- and ˂1-fold, respectively. Crossing experiments revealed that acequinocyl resistance in the ACE6 population was intermediately dominant and monogenic. In addition, the detoxifying enzyme activities were increased 3.03-fold for esterase, ˂1-fold for GST and 1.00-fold for cytochrome P450 monooxygenase in the ACE6 population. The results suggest that esterase enzyme may play a role in acequinocyl resistance, while the GST and P450 enzymes do not appear to have any significant involvement.

Trypanosoma cruzi mitochondrial swelling and membrane potential collapse as primary evidence of the mode of action of naphthoquinone analogues

BackgroundNaphthoquinones (NQs) are privileged structures in medicinal chemistry due to the biological effects associated with the induction of oxidative stress. The present study evaluated the activities of sixteen NQs derivatives on Trypanosoma cruzi.ResultsFourteen NQs displayed higher activity against bloodstream trypomastigotes of T. cruzi than benznidazole. Further assays with NQ1, NQ8, NQ9 and NQ12 showed inhibition of the proliferation of axenic epimastigotes and intracelulluar amastigotes interiorized in macrophages and in heart muscle cells. NQ8 was the most active NQ against both proliferative forms of T. cruzi. In epimastigotes the four NQs induced mitochondrial swelling, vacuolization, and flagellar blebbing. The treatment with NQs also induced the appearance of large endoplasmic reticulum profiles surrounding different cellular structures and of myelin-like membranous contours, morphological characteristics of an autophagic process. At IC50 concentration, NQ8 totally disrupted the ΔΨm of about 20% of the parasites, suggesting the induction of a sub-population with metabolically inactive mitochondria. On the other hand, NQ1, NQ9 or NQ12 led only to a discrete decrease of TMRE + labeling at IC50 values. NQ8 led also to an increase in the percentage of parasites labeled with DHE, indicative of ROS production, possibly the cause of the observed mitochondrial swelling. The other three NQs behaved similarly to untreated controls.ConclusionsNQ1, NQ8, NQ9 and NQ12 induce an autophagic phenotype in T. cruzi epimastigoted, as already observed with others NQs. The absence of oxidative stress in NQ1-, NQ9- and NQ12-treated parasites could be due to the existence of more than one mechanism of action involved in their trypanocidal activity, leaving ROS generation suppressed by the detoxification system of the parasite. The strong redox effect of NQ8 could be associated to the presence of the acetyl group in its structure facilitating quinone reduction, as previously demonstrated by electrochemical analysis. Further experiments using biochemical and molecular approaches are needed to better characterize ROS participation in the mechanism of action of these NQs.

Combined Three Dimensional Quantitative Structure Activity Relationships (3D-QSAR) Modeling and Molecular Docking Studies on Naphthoquinone Analogs as Proteasome Inhibitors

Proteasome inhibitors have been proved to be effective in regulated intracellular proteolysis. Three Dimensional Quantitative Structure Activity Relationships and Molecular docking methods were performed on naphthoquinone analogs as proteasome inhibitors. The bioactive conformation was explored by docking the potent compound 29 into the β5 and β6 subunit of the 20S proteasome. The constructed CoMFA and CoMSIA models produced statistically significant results with the cross-validated correlation coefficients q2 of 0.831 and 0.851, non-cross-validated correlation coefficients r2 of 0.974 and 0.965, and predicted correction coefficients r2 pred of 0.758 and 0.701, respectively. A set of 15 new analogs were proposed by utilizing the results revealed in the present study, and were predicted with significantly improved potencies in the developed models.

Combined Three Dimensional Quantitative Structure Activity Relationships (3D-QSAR) Modeling and Molecular Docking Studies on Naphthoquinone Analogs as Proteasome Inhibitors

Combined Three Dimensional Quantitative Structure Activity Relationships (3D-QSAR) Modeling and Molecular Docking Studies on Naphthoquinone Analogs as Proteasome Inhibitors

NMR Studies Reveal an Unexpected Binding Site for a Redox Inhibitor of AP Endonuclease 1

AP endonuclease 1 (APE1) is a multifaceted protein with essential roles in DNA repair and transcriptional regulation. APE1 (ref-1) activates many transcription factors (TF), including AP-1 and NF-κB. While the mechanism of APE1 redox activity remains unknown, it may involve reduction of an oxidized Cys in the TF DNA-binding domain. Several small molecules inhibit APE1-mediated TF activation, including the quinone derivative E3330. It has been proposed some inhibitors bind near C65, a residue suggested to be important for TF activation, but the binding site has not been determined for any inhibitor. Remarkably, NMR and molecular docking studies here reveal E3330 binds in the DNA repair active site of APE1, far removed from C65. Accordingly, AP endonuclease activity is substantially inhibited by E3330 (100 μM), suggesting that E3330 may not selectively inhibit APE1 redox activity in cells, in contrast with previous proposals. A naphthoquinone analogue of E3330, RN7-60, binds a site removed from both C65 and the repair active site. While a detailed understanding of how these inhibitors work requires further studies into the mechanism of redox activity, our results do not support proposals that E3330 binds selectively (and slowly) to locally unfolded APE1 or that E3330 promotes formation of disulfide bonds in APE1. Rather, we suggest E3330 may suppress a conformational change needed for redox activity, disrupt productive APE1-TF binding, or block the proposed redox chaperone activity of APE1. Our results provide the first structural information for any APE1 redox inhibitor and could facilitate development of improved inhibitors for research and perhaps clinical purposes.

ChemInform Abstract: Synthesis and anti‐Trypanosoma cruzi Activity of β‐Lapachone Analogues.

AbstractThe naphthoquinone analogues of β‐lapachone are obtained from methylene and aryl o‐quinone methides, generated in situ by Knoevenagel condensation of lawsone (I) with paraformaldehyde (II) or aryl aldehydes (IX), followed by hetero Diels—Alder reaction with different dienophiles.

Synthesis and anti- Trypanosoma cruzi activity of β-lapachone analogues

The available chemotherapy for Chagas disease, caused by Trypanosoma cruzi, is unsatisfactory; therefore, there is an intense effort to find new drugs for the treatment of this disease. In our laboratory, we have analyzed the effect on bloodstream trypomastigotes of 16 new naphthoquinone analogues of β-lapachone modified in the pyran ring, aiming to find a new prototype with high trypanocidal activity. The new compounds presented a broad spectrum of activity, and five of them presented IC 50/24 h in the range of 22–63 μM, whereas β-lapachone had a higher value of 391.5 ± 16.5 μM.

Studies on filarial GST as a target for antifilarial drug development—in silico and in vitro inhibition of filarial GST by substituted 1,4-naphthoquinones

Eleven 1,4-naphthoquinone analogues with different amino substitutions at position 3 of the quinone ring earlier reported for macrofilaricidal activity were selected and screened against purified cytosolic GST isolated from the bovine filarial worm Setaria digitata and IC(50) values were determined. Of the 11 compounds tested, 8 showed good inhibition against S. digitata GST. The IC(50) values of the most effective macrofilaricidal compounds-11 [2-(4-methylpiperazin-1-yl)naphthalene-1,4-dione] and 9 {2-[(1,3-dimethylbutyl)amino]naphthalene -1,4-dione}-were 0.872 and 0.994 mM, respectively. Compounds 9 and 11 were further studied for type of enzyme inhibition and found to exhibit competitive and uncompetitive inhibition kinetics, respectively, with respect to substrate GSH. All 11 compounds were in agreement with Lipinski's rule of five and passed through the FAFDrugs ADME/tox filter. Molecular docking was carried out using the modeled 3D structure of wbGST PDB ID:1SFM as receptor and substituted naphthoquinones as ligands using AutoDock 4.0. The binding energy of nine compounds varied from -9.15 to -6.58 Kcal mol(-1), whereas compounds 8 and 10 did not show any binding to the receptor. Among the compounds studied, compound 7 {2-[3-(diethylamino) propyl]aminonaphthalene-1,4-dione} showed maximum affinity towards wbGST as it exhibited the lowest binding energy, followed by compounds 11 and 9. However compound 7 was not macrofilaricidal while 11 and 9 exhibited macrofilaricidal activity. The results of in silico and in vitro studies with the synthesized 1,4 -naphthoquinone analogues on filarial GST and in vitro macrofilaricidal activity against adult bovine filarial worm S. digitata open up a promising biochemical target for antifilarial drug development.