Characterization of colchicine binding with normal and glycated albumin: In vitro and molecular docking analysis

Protective effect of colchicine on albumin glycation and cellular oxidative stress: Insights into diabetic cardiomyopathy

The present work elucidates the role of colchicine (COL) on albumin glycation and cellular oxidative stress in diabetic cardiomyopathy (DCM). Human serum albumin (HSA) was glycated with methylglyoxal in the presence of COL (2.5, 3.75, and 5 µM), whereas positive and negative control samples were maintained separately. The effects of COL on HSA glycation, structural and functional modifications in glycated HSA were analyzed using different spectroscopical and fluorescence techniques. Increased fructosamine, carbonyl, and pentosidine formation in glycated HSA samples were inhibited in the presence of COL. Structural conformation of HSA and glycated HSA samples was examined by field emission scanning electron microscopy, circular dichroism, Fourier transform infrared, and proton nuclear magnetic resonance analyses, where COL maintained both secondary and tertiary structures of HSA against glycation. Functional marker assays included ABTS•+ radical scavenging and total antioxidant activities, advanced oxidative protein product formation, and turbidimetry, which showed preserved functional properties of glycated HSA in COL-containing samples. Afterward, rat cardiomyoblast (H9c2 cell line) was treated with glycated HSA-COL complex (400 μg/mL) for examining various cellular antioxidants (nitric oxide, catalase, superoxide dismutase, and glutathione) and detoxification enzymes (aldose reductase, glyoxalase I, and II) levels. All three concentrations of COL exhibited effective anti-glycation properties, enhanced cellular antioxidant levels, and detoxification enzyme activities. The report comprehensively analyzes the potential anti-glycation and properties of COL during its initial assessment.

Study of Amiloride Binding to Human Serum Albumin: Insights from Thermodynamic, Spectroscopic, and Molecular Docking Investigations

This study was undertaken to investigate the interaction between the sodium channel blocker amiloride (AML) and human serum albumin (HSA). A combination of multi-spectroscopic techniques and computational methods were employed to identify the AML binding site on HSA and the forces responsible for the formation of the HSA-AML complex. Our findings revealed that AML specifically binds to Sudlow's site II, located in subdomain IIIA of HSA, and that the complex formed is stabilized using van der Waals hydrogen-bonding and hydrophobic interactions. FRET analysis showed that the distance between AML and Trp214 was optimal for efficient quenching. UV-Vis spectroscopy and circular dichroism indicated minor changes in the structure of HSA after AML binding, and molecular dynamics simulations (MDS) conducted over 100 ns provided additional evidence of stable HSA-AML-complex formation. This study enhances understanding of the interaction between AML and HSA and the mechanism responsible.

Celecoxib, Glipizide, Lapatinib, and Sitagliptin as potential suspects of aggravating SARS-CoV-2 (COVID-19) infection: a computational approach

COVID-19 caused by SARS-CoV-2 has emerged as a potential threat to human life, especially to people suffering from chronic diseases. In this study, we investigated the ability of selected FDA-approved drugs to inhibit TACE (tumor necrosis factor α converting enzyme), which is responsible for the shedding of membrane-bound ACE2 (angiotensin-converting enzyme2) receptors into soluble ACE2. The inhibition of TACE would lead to an increased population of membrane-bound ACE2, which would facilitate ACE2-Spike protein interaction and viral entry. A total of 50 drugs prescribed in treating various chronic diseases in Saudi Arabia were screened by performing molecular docking using AutoDock4.2. Based on docking energy (≤ -9.00 kcal mol^-1), four drugs (Celecoxib, Glipizide, Lapatinib, and Sitagliptin) were identified as potential inhibitors of TACE, with binding affinities up to 10⁶-10⁷ M^-1. Analysis of the molecular docking suggests that these drugs were bound to TACE's catalytic domain and interact with the key residues such as His405, Glu406, and His415, which are involved in active site Zn²⁺ ion chelation. Molecular dynamics simulation was performed to confirm the stability of TACE-drugs complexes. RMSD (root mean square deviation), RMSF (root mean square fluctuation), Rg (radius of gyration), and SASA (solvent accessible surface area) were within the acceptable limits. Free energy calculations using Prime-MM/GBSA suggest that Celecoxib formed the most stable complex with TACE, followed by Glipizide, Sitagliptin, and Lapatinib. The finding of this study suggests a mechanism for drugs to aggravate SARS-CoV-2 infection and hence high mortality in patients suffering from chronic diseases.Communicated by Ramaswamy H. Sarma.

Antioxidant and antimicrobial potential of two extracts from Capparis spinosa L. and Rumex nervosus and molecular docking investigation of selected major compounds

The present study examined the phytochemical composition, antioxidant, antimicrobial properties, and molecular docking of different solvents extracts (methanol and water) of two medicinal plants, namely, Capparis spinosa L (CS) and Rumex nervosus (RN). Phytochemical analysis showed that total phenol, flavonoids, alkaloids, and vitamin C were significantly (P ≤ 0.05) higher in the methanolic extract of both plants than in other solvents. However, tannin content was significantly (P ≤ 0.05) high in the water extract for both plants. Chloroform and acetone extracts were significantly lower in phytochemicals than other solvents, therefore excluded in this study. GC–MS analysis showed one dominant compound in CS (isopropyl isothiocyanate) and two in RN (pyrogallol and palmitic acid). The antioxidant methods applied (DPPH, ABTS, β-Carotene/linoleic acid assay, and reducing the power) showed that the methanolic extract of CS exerted higher activity in methanolic extract but lower than that of BHA standard. The methanolic extract of both plants inhibited the bacterial pathogens when a minimum inhibitory concentration (MIC) method was applied, compared to water extract with RN-methanolic extract had a lower inhibition concentration than CS-methanolic extract. The molecular interactions study revealed that the palmitic acid and pyrogallol interacted with the receptors' active site. This work concluded that CS and RN showed a remarkable antioxidant and antibacterial effect with the high antimicrobial activity of RN extract.

Antimicrobial Activity of Dihydroisocoumarin Isolated from Wadi Lajab Sediment-Derived Fungus Penicillium chrysogenum: In Vitro and In Silico Study

Antibiotic resistance is considered a major health concern globally. It is a fact that the clinical need for new antibiotics was not achieved until now. One of the most commonly prescribed classes of antibiotics is β-Lactam antibiotics. However, most bacteria have developed resistance against β-Lactams by producing enzymes β-Lactamase or penicillinase. The discovery of new β-Lactamase inhibitors as new antibiotics or antibiotic adjuvants is essential to avoid future catastrophic pandemics. In this study, five dihydroisocoumarin: 6-methoxy mellein (1); 5,6-dihydroxymellein (2); 6-hydroxymellein (3); 4-chloro-6-hydroxymellein (4) and 4-chloro-5,6-di-hydroxymellein (5) were isolated from Wadi Lajab sediment-derived fungus Penicillium chrysogenum, located 15 km northwest of Jazan, KSA. The elucidation of the chemical structures of the isolated compounds was performed by analysis of their NMR, MS. Compounds 1–5 were tested for antibacterial activities against Gram-positive and Gram-negative bacteria. All of the compounds exhibited selective antibacterial activity against Gram-positive bacteria Staphylococcus aureus and Bacillus licheniformis except compound 3. The chloro-dihydroisocoumarin derivative, compound 4, showed potential antimicrobial activities against all of the tested strains with the MIC value between 0.8–5.3 μg/mL followed by compound 5, which exhibited a moderate inhibitory effect. Molecular docking data showed good affinity with the isolated compounds to β-Lactamase enzymes of bacteria; NDM-1, CTX-M, OXA-48. This work provides an effective strategy for compounds to inhibit bacterial growth or overcome bacterial resistance.

The Antiproliferative and Apoptotic Effects of a Novel Quinazoline Carrying Substituted-Sulfonamides: In Vitro and Molecular Docking Study

In order to investigate for a new effective and safe anticancer drug, we synthesized a novel series of quinazoline containing biologically active substituted-sulfonamide moiety at 3- position 4a-n. The structure of the newly prepared compounds was proved by microanalysis, IR, ¹H-NMR, ¹³C-NMR and mass spectral data. All the synthesized compounds were evaluated for their in vitro cytotoxic activity in numerous cancer cell lines including A549, HepG-2, LoVo and MCF-7 and normal HUVEC cell line. The two most active compounds 4d and 4f were then tested for their apoptosis induction using DNA content and Annexin V-FITC/PI staining. Moreover, apoptosis initiation was also confirmed using RT-PCR and Western blot. To further understand the binding preferences of quinazoline sulfonamides, docking simulations were used. Among the fourteen new synthesized compounds, we found that compounds 4d and 4f exerted the strongest cytotoxicity against MCF-7 cells with an IC₅₀ value of 2.5 and 5 μM, respectively. Flow cytometry data revealed the ability of compounds 4d and 4f to mediate apoptosis and arrest cell cycle growth at G1 phase. Furthermore, RT-PCR and Western blot results suggested that both 4d and 4f activates apoptotic cell death pathway in MCF-7 cells. Molecular docking assessments indicated that compounds 4d and 4f fit perfectly into Bcl2's active site. Based on the biological properties, we conclude that both compounds 4d and 4f could be used as a new type of anticancer agent, which provides a scientific basis for further research into the treatment of cancer.

Novel sulphonamide-bearing methoxyquinazolinone derivatives as anticancer and apoptosis inducers: synthesis, biological evaluation and in silico studies

We synthesised a new series of sulphonamide-bearing quinazolinone derivatives 5-18 and evaluated their in vitro cytotoxicity in various cancer cell lines (A549, HepG-2, LoVo and MCF-7) and in normal human cells (HUVEC). Compounds 6 and 10 exhibited the higher activity against all the cancer cell lines compared with 5-flourourcil as positive control. The ability of the most promising compounds 6 and 10 to induce cell cycle arrest and apoptosis in breast cancer (MCF-7) cells was evaluated by flow cytometry. Reverse transcriptase-polymerase chain reaction and western blotting were used to evaluate the expression of apoptosis-related markers. We found that the 2-tolylthioacetamide derivative 6 and the 3-ethyl phenyl thioacetamide derivative 10 exhibited cytotoxic activity comparable to that of 5-fluorouracil as reference drug in MCF-7 and LoVo colon cancer cells. Cell cycle analysis showed a concentration-dependent accumulation of cells in the sub-G1 phase upon treatment with both compounds. The Annexin V-fluorescein isothiocyanate/propidium iodide assay showed that the compounds 6 and 10 increased the early and late apoptosis cell death modes in a dose-dependent manner. These compounds downregulated the expression of B-cell lymphoma-2 (Bcl-2), while increasing that of p53, Bcl-2-like protein 4, and caspase-7, at the mRNA and protein levels. Molecular docking of compounds 6 and 10 with Bcl-2 predicted them to show moderate − high binding affinity (6: −7.5 kcal/mol, 10: −7.9 kcal/mol) and interactions with key central substrate cavity residues. Overall, compounds 6 and 10 were found to be promising anticancer and apoptosis-inducing agents.

Exploring the Binding Pattern of Geraniol with Acetylcholinesterase through In Silico Docking, Molecular Dynamics Simulation, and In Vitro Enzyme Inhibition Kinetics Studies

Acetylcholinesterase (AChE) inhibition is a key element in enhancing cholinergic transmission and subsequently relieving major symptoms of several neurological and neuromuscular disorders. Here, the inhibitory potential of geraniol and its mechanism of inhibition against AChE were elucidated in vitro and validated via an in silico study. Our in vitro enzyme inhibition kinetics results show that at increasing concentrations of geraniol and substrate, Vmax did not change significantly, but Km increased, which indicates that geraniol is a competitive inhibitor against AChE with an IC₅₀ value 98.06 ± 3.92 µM. All the parameters of the ADME study revealed that geraniol is an acceptable drug candidate. A docking study showed that the binding energy of geraniol (−5.6 kcal mol⁻¹) was lower than that of acetylcholine (−4.1 kcal mol⁻¹) with AChE, which exhibited around a 12.58-fold higher binding affinity of geraniol. Furthermore, molecular dynamics simulation revealed that the RMSD of AChE alone or in complex with geraniol fluctuated within acceptable limits throughout the simulation. The mean RMSF value of the complex ensures that the overall conformation of the protein remains conserved. The average values of Rg, MolSA, SASA, and PSA of the complex were 3.16 Å, 204.78, 9.13, and 51.58 Ų, respectively. We found that the total SSE of AChE in the complex was 38.84% (α-helix: 26.57% and β-sheets: 12.27%) and remained consistent throughout the simulation. These findings suggest that geraniol remained inside the binding cavity of AChE in a stable conformation. Further in vivo investigation is required to fully characterize the pharmacokinetic properties, optimization of dose administration, and efficacy of this plant-based natural compound.

High-Throughput Screening and Molecular Dynamics Simulation of Natural Product-like Compounds against Alzheimer's Disease through Multitarget Approach

Alzheimer’s disease (AD) is a progressive neurological disorder that affects 50 million people. Despite this, only two classes of medication have been approved by the FDA. Therefore, we have planned to develop therapeutics by multitarget approach. We have explored the library of 2029 natural product-like compounds for their multi-targeting potential against AD by inhibiting AChE, BChE (cholinergic pathway) MAO-A, and MOA-B (oxidative stress pathway) through in silico high-throughput screening and molecular dynamics simulation. Based on the binding energy of these target enzymes, approximately 189 compounds exhibited a score of less than −10 kcal/mol against all targets. However, none of the control inhibitors exhibited a binding affinity of less than −10 kcal/mol. Among these, the top 10 hits of compounds against all four targets were selected for ADME-T analysis. As a result, only F0850-4777 exhibited an acceptable range of physicochemical properties, drug-likeness, pharmacokinetics, and suitability for BBB permeation with high GI-A and non-toxic effects. The molecular dynamics study confirmed that F0850-4777 remained inside the binding cavity of targets in a stable conformation throughout the simulation and Prime-MM/GBSA study revealed that van der Waals’ energy (ΔG_vdW) and non-polar solvation or lipophilic energy (ΔG_{Sol_Lipo}) contribute favorably towards the formation of a stable protein–ligand complex. Thus, F0850-4777 could be a potential candidate against multiple targets of two pathophysiological pathways of AD and opens the doors for further confirmation through in vitro and in vivo systems.

Identification of Butyrylcholinesterase and Monoamine Oxidase B Targeted Ligands and their Putative Application in Alzheimer's Treatment: A Computational Strategy

BACKGROUND

With the burgeoning worldwide aging population, the incidence of Alzheimer's disease (AD) and its associated disorders is continuously rising. To appraise other relevant drug targets that could lead to potent enzyme targeting, 13 previously predicted ligands (shown favorable binding with AChE (acetylcholinesterase) and GSK-3 (glycogen synthase kinase) were screened for targeting 3 different enzymes, namely butyrylcholinesterase (BChE), monoamine oxidase A (MAO-A), and monoamine oxidase B (MAO-B) to possibly meet the unmet medical need of better AD treatment.

MATERIALS AND METHODS

The study utilized in silico screening of 13 ligands against BChE, MAO-A and MAOB using PyRx-Python prescription 0.8. The visualization of the active interaction of studied compounds with targeted proteins was performed by Discovery Studio 2020 (BIOVIA).

RESULTS

The computational screening of studied ligands revealed the docking energies in the range of -2.4 to -11.3 kcal/mol for all the studied enzymes. Among the 13 ligands, 8 ligands (55E, 6Z2, 6Z5, BRW, F1B, GVP, IQ6, and X37) showed the binding energies of ≤ -8.0 kcal/mol towards BChE, MAO-A and MAO-B. The ligand 6Z5 was found to be the most potent inhibitor of BChE and MAO-B, with a binding energy of -9.7 and -10.4 kcal mol, respectively. Molecular dynamics simulation of BChE-6Z5 and MAO-B-6Z5 complex confirmed the formation of a stable complex.

CONCLUSION

Our computational screening, molecular docking, and molecular dynamics simulation studies revealed that the above-mentioned enzymes targeted ligands might expedite the future design of potent anti-AD drugs generated on this chemical scaffold.

Elucidation of molecular interactions of theaflavin monogallate with camel milk lactoferrin: detailed spectroscopic and dynamic simulation studies

Lactoferrin is a heme-binding multifunctional glycoprotein known for iron transportation in the blood and also contributes to innate immunity. In this study, the interaction of theaflavin monogallate, a polyphenolic component of black tea, with camel milk lactoferrin was studied using various biophysical and computational techniques. Fluorescence quenching at different temperatures suggests that theaflavin monogallate interacted with lactoferrin by forming a non-fluorescent complex, i.e., static quenching. Theaflavin monogallate shows a significant affinity towards lactoferrin with a binding constant of ∼10⁴–10⁵ M⁻¹ at different temperatures. ANS binding shows that the binding of polyphenol resulted in the burial of hydrophobic domains of lactoferrin. Moreover, thermodynamic parameters (ΔH, ΔS and ΔG) suggested that the interaction between protein and polyphenol was entropically favored and spontaneous. Circular dichroism confirmed there was no alteration in the secondary structure of lactoferrin. The energy transfer efficiency (FRET) from lactoferrin to theaflavin was found to be approximately 50%, with a distance between protein and polyphenol of 2.44 nm. Molecular docking shows that the binding energy of lactoferrin–theaflavin monogallate interaction was −9.7 kcal mol⁻¹. Theaflavin monogallate was bound at the central cavity of lactoferrin and formed hydrogen bonds with Gln89, Tyr192, Lys301, Ser303, Gln87, and Val250 of lactoferrin. Other residues, such as Tyr82, Tyr92, and Tyr192, were involved in hydrophobic interactions. The calculation of various molecular dynamics simulations parameters indicated the formation of a stable complex between protein and polyphenol. This study delineates the binding mechanism of polyphenol with milk protein and could be helpful in milk formulations and play a key role in the food industry.

Lactoferrin is a heme-binding multifunctional glycoprotein known for iron transportation in the blood and also contributes to innate immunity.

How Does Glycation Affect Binding Parameters of the Albumin-Gliclazide System in the Presence of Drugs Commonly Used in Diabetes? In Vitro Spectroscopic Study

In this research, the selected drugs commonly used in diabetes and its comorbidities (gliclazide, cilazapril, atorvastatin, and acetylsalicylic acid) were studied for their interactions with bovine serum albumin-native and glycated. Two different spectroscopic methods, fluorescence quenching and circular dichroism, were utilized to elucidate the binding interactions of the investigational drugs. The glycation process was induced in BSA by glucose and was confirmed by the presence of advanced glycosylation end products (AGEs). The interaction between albumin and gliclazide, with the presence of another drug, was confirmed by calculation of association constants (0.11-1.07 × 10⁴ M^-1). The nature of changes in the secondary structure of a protein depends on the drug used and the degree of glycation. Therefore, these interactions may have an influence on pharmacokinetic parameters.

Inhibition behavior of Sennoside A and Sennoside C on amyloid fibrillation of human lysozyme and its possible mechanism

Amyloid proteins were recognized as the crucial cause of many senile diseases. In this study, the inhibitory effects of Sennoside A (SA) and Sennoside C (SC) on amyloid fibrillation were evaluated by the combination of biophysical approaches and molecular docking tool using human lysozyme (HL) as amyloid-forming model. The results of thioflavin-T (ThT), 8-anilino-1-naphthalenesulfonic acid (ANS) and congo red (CR) assays indicated that both SA and SC could inhibit the amyloid fibrillation of HL in a dose-dependent manner. The IC₅₀ value of SA and SC on HL fibrillation was 200.09 μM and 186.20 μM, respectively. These findings were further verified by transmission electron microscopy (TEM) and atomic force microscopy (AFM), which showed that the addition of SA or SC could sharply reduce the amyloid fibrillation of HL. Additionally, the interactions of HL with SA and SC were investigated by steady-state fluorescence spectra and molecular docking studies. The results suggested that both SA and SC could bind to the binding pocket of HL and form a stable complex mainly via hydrogen bonds, van-der-Waals forces and hydrophobic interactions. In conclusion, our experiments revealed that both SA and SC can significantly inhibit amyloid fibrillation of HL.

Impact of Different Extraction Methods on Furanosesquiterpenoids Content and Antibacterial Activity of Commiphora myrrha Resin

The oleo-gum-resin of Commiphora myrrha is one of the most known natural antimicrobial agents, mainly due to its furanosesquiterpenes. A validated method based on sample extraction by matrix solid-phase dispersion (MSPD) followed by high-performance column chromatography (HPLC) determination is applied to analyze two furanosesquiterpenoids, namely, 2-methoxyfuranodiene (CM-1) and 2-acetoxyfuranodiene (CM-2), existing in C. myrrha. The trial parameters that controlled the extraction prospective were studied and optimized. These include the nature of dispersant, mass ratio of sample to the dispersant, and the volume of elution solvent. A comparative antimicrobial study that used the Minimum Inhibitory Concentration Assay (MIC) method between MSPD, ultrasonic, and Soxhlet of myrrh extracts was also conducted. The optimal MSPD parameters used were (i) 15 mL of methanol applied as elution solvent; (ii) silica gel/sample mass at a 2 : 1 ratio; and (iii) a dispersing sorbent selected as silica gel. Technique retrievals were regulated from 96.87% to 100.54%, with relative standard deviations (RSDs) from 1.24% to 4.45%. Commiphora myrrha-MSPD (CM-MSPD) extract showed the highest antibacterial activity against gram-positive and gram-negative bacteria (156.25 μg/mL and 312.5 μg/mL, respectively) and antifungal activity (156.25 μg/mL). Yields acquired through the MSPD technique were larger than yields from other extraction techniques (sonication and traditional reflux extraction methods) with less consumption of time, sample, and solvent. The mode of antibacterial action of CM-1 and CM-2 was elucidated by performing molecular docking with bacterial DNA gyrase. Both the compounds interacted with key residues of DNA gyrase.

Structural Basis of Drug Recognition by Human Serum Albumin

Background:

Human serum albumin (HSA), the most abundant protein in plasma, is a monomeric multi-domain macromolecule with at least nine binding sites for endogenous and exogenous ligands. HSA displays an extraordinary ligand binding capacity as a depot and carrier for many compounds including most acidic drugs. Consequently, HSA has the potential to influence the pharmacokinetics and pharmacodynamics of drugs.

Objective:

In this review, the structural determinants of drug binding to the multiple sites of HSA are analyzed and discussed in detail. Moreover, insight into the allosteric and competitive mechanisms underpinning drug recognition, delivery, and efficacy are analyzed and discussed.

Conclusion:

As several factors can modulate drug binding to HSA (e.g., concurrent administration of drugs competing for the same binding site, ligand binding to allosteric-coupled clefts, genetic inherited diseases, and post-translational modifications), ligand binding to HSA is relevant not only under physiological conditions, but also in the pharmacological therapy management.

Inhibition of CpLIP2 Lipase Hydrolytic Activity by Four Flavonols (Galangin, Kaempferol, Quercetin, Myricetin) Compared to Orlistat and Their Binding Mechanisms Studied by Quenching of Fluorescence

The inhibition of recombinant CpLIP2 lipase/acyltransferase from Candida parapsiolosis was considered a key model for novel antifungal drug discovery and a potential therapeutic target for candidiasis. Lipases have identified recently as potent virulence factors in C. parapsilosis and some other yeasts. The inhibition effects of orlistat and four flavonols (galangin, kaempferol, quercetin and myricetin) characterized by an increasing degree of hydroxylation in B-ring, were investigated using ethyl oleate hydrolysis as the model reaction. Orlistat and kaempferol (14 µM) strongly inhibited CpLIP2 catalytic activity within 1 min of pre-incubation, by 90% and 80%, respectively. The relative potency of flavonols as inhibitors was: kaempferol > quercetin > myricetin > galangin. The results suggested that orlistat bound to the catalytic site while kaempferol interacted with W294 on the protein lid. A static mechanism of interactions between flavonols and CpLIP2 lipase was confirmed by fluorescence quenching analyses, indicating that the interactions were mainly driven by hydrophobic bonds and electrostatic forces. From the Lehrer equation, fractions of tryptophan accessibility to the quencher were evaluated, and a relationship with the calculated number of binding sites was suggested.

Plant-derived antiviral drugs as novel hepatitis B virus inhibitors: Cell culture and molecular docking study

Despite high anti-HBV efficacies, while the nucleoside analogs (e.g., lamivudine) lead to the emergence of drug-resistance, interferons (e.g., IFN-α causes adverse side-effects. Comparatively, various natural or plant products have shown similar or even better efficacy. Hence, new antiviral strategies must focus not only on synthetic molecules but also on potential natural compounds. In this report, we have combined the in vitro cell culture and in silico molecular docking methods to assess the novel anti-HBV activity and delineate the inhibitory mechanism of selected plant-derived pure compounds of different classes. Of the tested (2.5-50 μg/ml) twelve non-cytotoxic compounds, ten (10 μg/ml) were found to maximally inhibit HBsAg production at day 5. Compared to quercetin (73%), baccatin III (71%), psoralen (67%), embelin (65%), menisdaurin (64%) and azadirachtin (62%) that showed high inhibition of HBeAg synthesis, lupeol (52%), rutin (47%), β-sitosterol (43%) and hesperidin (41%) had moderate efficacies against HBV replication. Further assessment of quercetin in combination with the highly active compounds, enhanced its anti-HBV activity up to 10%. Being the most important drug target, a 3-D structure of HBV polymerase (Pol/RT) was modeled and docked with the active compounds, including lamivudine as standard. Docking of lamivudine indicated strong interaction with the modeled HBV Pol active-site residues that formed stable complex (∆G = -5.2 kcal/mol). Similarly, all the docked antiviral compounds formed very stable complexes with HBV Pol (∆G = -6.1 to -9.3 kcal/mol). Taken together, our data suggest the anti-HBV potential of the tested natural compounds as novel viral Pol/RT inhibitors.