Exploring the antimalarial and antioxidant efficacy of transition metal(II) chelates of thiosemicarbazone ligands: spectral investigations, molecular docking, DFT, MESP and ADMET.

Malaria, a relentless and ancient adversary, continues to cast its shadow over vast swathes of the globe, afflicting millions of people and have a heavy toll on human health and well-being. Despite substantial progress in the fight against this parasitic disease in recent decades, malaria still persists as a substantial global health concern, especially in some specific region which have limited resources and vulnerable populations. Thus, to ascertain an combating agent for malaria and its associated dysfunction, 4-(4-ethylphenyl)-3-thiosemicarbazide and benzaldehydes based two new thiosemicarbazone ligands (1-2) and their cobalt(II), nickel(II), copper(II), zinc(II) metal complexes (3-10) were synthesized in the present research work. The synthesized compounds were comprehensive characterized through spectral and physical investigations, demonstrating octahedral stereochemistry of the complexes. Further, the antimalarial and antioxidant potential of the compounds (1-10) were analyzed by micro assay and DPPH assay protocols, respectively, to examine the therapeutic aspect of the compounds. The performed biological evaluations revealed that the complexes are more efficient in controlling infectious ailment in comparison of ligands. The complexes (5), (6), (10) shows significant efficiency for malarial and oxidant dysfunctions whereas Zn(II) complex (6) exhibit highest potency with 1.02 ± 0.07 and 2.28 ± 0.05 µM IC50 value. Furthermore, to support the highest antimalarial potency of the (3-6) complexes and their associated ligand (1), the computational studies like molecular docking, DFT, MESP and ADMET analysis were executed which were supported the biological efficacy of the complex (6) by providing numerous parameters like binding interaction electronegativity, electrophilicity, HOMO value and electron density.

Experimental and computational evaluation of anti-malarial and antioxidant potential of transition metal (II) complexes with tridentate schiff base derived from pyrrolopyrimidine.

In the twenty-first century, we are experiencing persistent waves of diverse pathogen variations, contributing significantly to global illness and death rates. Within this varied spectrum of illnesses, malaria and oxidative damage emerge as prominent obstacles that have persistently affected human health. The motivation for exploring the antioxidant potential of transition metal (II) complexes with tridentate Schiff base ligands is driven by the need for effective treatments against malaria and oxidative stress-related conditions. Both malaria and oxidative damage are significant global health concerns. Transition metal complexes can potentially offer enhanced anti-malarial and antioxidant activities, providing a dual benefit. To explore the aforementioned facts and examine the therapeutic potential, the previously synthesized pyrrolopyrimidinehydrazide-3-chlorobenzaldehyde, such as HPPHmCB ligand(1)andtheirMn(II),Fe(II),Co(II),Ni(II), Pd(II),Cu(II),Zn(II),Cd(II),Hg(II)complexes(2-10) of benzaldehydes and pyrrolopyrimidinehydrazide were proposed for in vitro anti-malarial and antioxidant investigation. These compounds were assessed for their anti-malarial efficacy against Plasmodium falciparum using a micro assay protocol, with IC50 values indicating the concentration required to inhibit parasite maturation by 50%. The Hg(II) complex displays pronounced antimalarial activity with an IC50 value of 1.98 ± 0.08 µM, closely aligning with the efficacy of quinine, whereas Zn(II), Cu(II), Pd(II) complexes demonstrates most significant anti-malarial activity, with IC50 values close to the reference compound quinine. The antioxidant activity of the compounds was evaluated using the DPPH assay, with several metal complexes such as Cu(II)and Zn(II) showing strong potential in neutralizing oxidative stress. Furthermore, molecular docking simulations were conducted to explore the binding interactions of the compounds with PfNDH2, providing insights into their pharmacological potential. The study also examined the electronic properties, solubility, and potential hepatotoxicity of the compounds. The findings suggest that the metal complexes could be promising candidates for further development as anti-malarial agents, offering enhanced potency compared to the base compound.

Organotellurium (IV) complexes as anti-malarial agents: synthesis, characterization and computational insights.

Aim: To synthesize and evaluate the antimalarial and antioxidant activities of novel organotellurium (IV) thiophene-based complexes.Materials & methods: Synthesized complexes were characterized using NMR, IR and mass spectrometry. Their biological activities were assessed using in vitro assays and molecular docking studies.Results: The complexes exhibited significant antimalarial activity against Plasmodium falciparum, with the highest activity observed for complexes 5b and 5e. ADMET properties confirmed their potential as therapeutic agents.

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Synergistic Activity of Noble Trimetallic Nanofluids: Unveiling Unprecedented Antimicrobial Potential and Computational Insights.

Nanofluids hold significant promise in diverse applications, particularly in biomedicine, where noble trimetallic nanofluids outperformed their monometallic counterparts. The composition, morphology, and size of these nanofluids play pivotal roles in their functionality. Controlled synthesis methods have garnered attention, focusing on precise morphology, content, biocompatibility, and versatile chemistry. Understanding how reaction parameters such as time, reducing agents, stabilizers, precursor concentration, temperature, and pH affect size and shape during synthesis is crucial. Trimetallic nanofluids, with their ideal composition, size, surface structure, and synergistic properties, are gaining traction in antimicrobial applications. These nanofluids were tested against seven microorganisms, demonstrating a heightened antimicrobial efficacy. Computational analyses, including molecular docking, dynamics, density functional theory (DFT), molecular electrostatic potential (MESP) analysis, and absorption, distribution, metabolism, elimination, and toxicology studies (ADMET) provided insights into binding interactions, energy, reactivity, and safety profiles, affirming the antimicrobial potential of trimetallic nanofluids. These findings emphasize the importance of controlled synthesis and computational validation in harnessing the unique properties of trimetallic nanofluids for biomedical applications.

ADME profiling, molecular docking, DFT, and MEP analysis reveal cissamaline, cissamanine, and cissamdine from Cissampelos capensis L.f. as potential anti-Alzheimer's agents.

The current pharmacotherapies for Alzheimer's disease (AD) demonstrate limited efficacy and are associated with various side effects, highlighting the need for novel therapeutic agents. Natural products, particularly from medicinal plants, have emerged as a significant source of potential neuroprotective compounds. In this context, Cissampelos capensis L.f., renowned for its medicinal properties, has recently yielded three new proaporphine alkaloids; cissamaline, cissamanine, and cissamdine. Despite their promising bioactive profiles, the biological targets of these alkaloids in the context of AD have remained unexplored. This study undertakes a comprehensive in silico examination of the binding affinity and molecular interactions of these alkaloids with human protein targets implicated in AD. The drug likeness and ADME analyses indicate favorable pharmacokinetic profiles for these compounds, suggesting their potential efficacy in targeting the central nervous system. Molecular docking studies indicate that cissamaline, cissamanine, and cissamdine interact with key AD-associated proteins. These interactions are comparable to, or in some aspects slightly less potent than, those observed with established AD drugs, highlighting their potential as novel therapeutic agents for Alzheimer's disease. Crucially, Density Functional Theory (DFT) calculations offer deep insights into the electronic and energetic characteristics of these alkaloids. These calculations reveal distinct electronic properties, with differences in total energy, binding energy, HOMO-LUMO gaps, dipole moments, and electrophilicity indices. Such variations suggest unique reactivity profiles and molecular stability, pertinent to their pharmacological potential. Moreover, Molecular Electrostatic Potential (MEP) analyses provide visual representations of the electrostatic characteristics of these alkaloids. The analyses highlight areas prone to electrophilic and nucleophilic attacks, indicating their potential for specific biochemical interactions. This combination of DFT and MEP results elucidates the intricate electronic, energetic, and electrostatic properties of these compounds, underpinning their promise as AD therapeutic agents. The in silico findings of this study shed light on the promising potential of cissamaline, cissamanine, and cissamdine as agents for AD treatment. However, further in vitro and in vivo studies are necessary to validate these theoretical predictions and to understand the precise mechanisms through which these alkaloids may exert their therapeutic effects.

Insights from in silico exploration of major curcumin analogs targeting human dipeptidyl peptidase IV.

The goal of this work is to use a variety of in-silico techniques to identify anti-diabetic agents against DPP-IV enzyme from five main curcumin analogues. To produce the successful molecules, five main curcumin analogues were docked into the active site of DPP-IV enzyme. In comparison to the control molecule (Saxagliptin, -6.9 kcal/mol), all the compounds have the highest binding affinity (-7.6 to -7.7 kcal/mol) for the DPP-IV enzyme. These compounds underwent further testing for studies on drug-likeness, pharmacokinetics, and acute toxicity to see the efficacy and safety of compounds. To assess the stability of the docking complex and the binding posture identified during the docking experiment, our study got THC as the lead compound, which was then exposed to 200 ns of molecular dynamic simulation and PCA analysis. Additionally, DFT calculations were conducted to determine the thermodynamic, molecular orbital, and electrostatic potential characteristics of lead compound. Overall, the lead chemical has shown strong drug-like properties, is non-toxic, and has a sizable affinity for the DPP-IV enzyme.Communicated by Ramaswamy H. Sarma.

Phenolic compounds of Theobroma cacao L. show potential against dengue RdRp protease enzyme inhibition by In-silico docking, DFT study, MD simulation and MMGBSA calculation.

BACKGROUND: Currently, there is no antiviral medication for dengue, a potentially fatal tropical infectious illness spread by two mosquito species, Aedes aegypti and Aedes albopictus. The RdRp protease of dengue virus is a potential therapeutic target. This study focused on the in silico drug discovery of RdRp protease inhibitors. METHODS: To assess the potential inhibitory activity of 29 phenolic acids from Theobroma cacao L. against DENV3-NS5 RdRp, a range of computational methods were employed. These included docking, drug-likeness analysis, ADMET prediction, density functional theory (DFT) calculations, and molecular dynamics (MD) simulations. The aim of these studies was to confirm the stability of the ligand-protein complex and the binding pose identified during the docking experiment. RESULTS: Twenty-one compounds were found to have possible inhibitory activities against DENV according to the docking data, and they had a binding affinity of ≥-37.417 kcal/mol for DENV3- enzyme as compared to the reference compound panduratin A. Additionally, the drug-likeness investigation produced four hit compounds that were subjected to ADMET screening to obtain the lead compound, catechin. Based on ELUMO, EHOMO, and band energy gap, the DFT calculations showed strong electronegetivity, favouravle global softness and chemical reactivity with considerable intra-molecular charge transfer between electron-donor to electron-acceptor groups for catechin. The MD simulation result also demonstrated favourable RMSD, RMSF, SASA and H-bonds in at the binding pocket of DENV3-NS5 RdRp for catechin as compared to panduratin A. CONCLUSION: According to the present findings, catechin showed high binding affinity and sufficient drug-like properties with the appropriate ADMET profiles. Moreover, DFT and MD studies further supported the drug-like action of catechin as a potential therapeutic candidate. Therefore, further in vitro and in vivo research on cocoa and its phytochemical catechin should be taken into consideration to develop as a potential DENV inhibitor.

Investigation of antituberculosis, antimicrobial, anti-inflammatory efficacies of newly synthesized transition metal(II) complexes of hydrazone ligands: structural elucidation and theoretical studies.

Tuberculosis disease is a serious threat to humans and spreading quickly worldwide, therefore, to find a potent drug, the synthesis of hydrazone ligands endowed Co(II), Ni(II), Cu(II), Zn(II) metal complexes were carried out and well characterized by numerous spectral and analytical techniques. The octahedral geometry of the complexes was confirmed by spectral analysis. Further, in vitro antituberculosis efficacy of the compounds (1-10) revealed that complexes (6), (9), (10) have highest potency to control TB malformation with 0.0028 ± 0.0013-0.0063 ± 0.0013 µmol/mL MIC value while Zn(II) complex (10) (0.0028 ± 0.0013 µmol/mL) has nearly four time potent to suppress TB disease in comparison of streptomycin (0.0107 ± 0.0011 µmol/mL). The antimicrobial and anti-inflammatory evaluations revealed that the complex (10) is more active with lowest MIC (0.0057-0.0114 µmol/mL) and IC50 (7.14 ± 0.05 µM) values, correspondingly which are comparable with their respective standard drugs. Furthermore, the theoretical studies such as molecular docking, DFT, MESP and ADMET were employed to authenticate the potency of HL2 hydrazone ligand (2) and its metal complexes (7-10) which revealed that the zinc(II) complex (10) might be utilized as novel drug candidate for tuberculosis dysfunctions. So, the present research gives a new insight for in vivo investigation of the compounds.

Biological and computational investigation of transition metal(II) complexes of 2-phenoxyaniline-based ligands.

Aim: In the 21st century, we are witness of continuous onslaughts of various pathogen deformities which are a major cause of morbidity and mortality worldwide. Therefore, to investigate the grave for these deformities, antioxidant, anti-inflammatory and antimicrobial biological activities were carried out against newly synthesized Schiff base ligands and their transition metal complexes, which are based on newly synthesized 2-phenoxyaniline and salicylaldehyde derivatives. Materials & methods: The synthesized compounds were characterized by various physiochemical studies, demonstrating the octahedral stereochemistry of the complexes. Results: The biological assessments revealed that complex 6 (3.01 ± 0.01 µM) was found to be highly active for oxidant ailments whereas complex 14 (7.14 ± 0.05 µM, 0.0041-0.0082 µmol/ml) was observed as highly potent for inflammation and microbial diseases. Conclusion: Overall, the biological and computational studies demonstrate that the nickel(II) complex 14 can act as an excellent candidate for pathogen deformities.

Synthesis, spectroscopic investigation, molecular docking, ADME/T toxicity predictions, and DFT study of two trendy ortho vanillin-based scaffolds.

In this article, we have synthesized two contemporary ortho-vanillin-based Salen-type ligands (H2L1/H2L2) characterized by modern spectroscopic tools. EDX analysis supports the elemental composition (C, N, O, and Br). SEM examined the morphology of the synthesized compounds. The molecular geometry was optimized in the gas phase using B3LYP-D3/6-311G (d, p) level. The global reactivity parameters, HOMO-LUMO energy gap (Δ), atomic properties, MESP, and ADME/T, vividly explore the chemical reactivity and toxicity of two Salen-type ligands. The DFT simulated IR/NMR characterized essential structural assignments, and UV-Visible spectra were employed to predict the optical properties. The article demonstrated in silico molecular docking against the Gm + ve Bacillus subtilis (6UF6), and Gm -ve Proteus Vulgaris establishes the ligand binding ability with essential amino acids through conventional H-bonding or other significant interactions. The docking simulation is compared for two compounds better than the control drugs and confirms the antimicrobial activity. The theoretical drug-like properties have been explored in-depth by ADME/T using the SWISSADME database. The analysis estimated the molecule's lipophilicity, the consensus P0/W, and water solubility. Thus, using various pharmaco-logical parameters, toxicity explains where the electron-withdrawing Br group plays a more toxic effect in H2L2 than in H2L1.

Synthesis, spectroscopic findings, SEM/EDX, DFT, and single-crystal structure of Hg/Pb/Cu-SCN complexes: In silico ADME/T profiling and promising antibacterial activities.

This work contemplates synthesizing M-SCN crystal compounds (M = Hg/Pb/Cu) in the presence of respective metal salts and exogenous ancillary SCN- ion by slowly evaporating the mixed solvent (CH3OH + ACN). The complexes were characterized by spectroscopy, SEM/EDX, and X-ray crystallography. The Hg-Complex, Pb-Complex, and Cu-Complex crystallize in the monoclinic space group (Z = 2/4). The crystal packing fascinatingly consists of weak covalent bonding and Pb⋯S contacts of tetrel type bond. Here are the incredible supramolecular topographies delineated by the Hirshfeld surface and 2D fingerprint plot. The B3LYP/6-311++G (d, p) level calculations in the gas phase optimized the compound's geometry. The energy difference (Δ) between HOMO-LUMO and global reactivity parameters investigates the complex's energetic activity. MESP highlights the electrophilic/nucleophilic sites and H-bonding interactions. Molecular docking was conceded with the Gram- + ve bacterium Bacillus Subtilis (PDB ID: 6UF6) and the Gram-ve bacterium Proteus Vulgaris (PDB ID: 5HXW) to authenticate the bactericidal activity. ADME/T explains the various pharmacological properties. In addition, we studied the antibacterial activity with MIC (µg/mL) values and time-kill kinetics against Staphylococcus aureus (ATCC 25923) and Bacillus subtilis (ATCC 6635) as Gram-positive, Pseudomonas aeruginosa (ATCC 27853) and Escherichia coli (ATCC 25922) as Gram-negative bacteria.

Computer-aided anti-cancer drug discovery of EGFR protein based on virtual screening of drug bank, ADMET, docking, DFT and molecular dynamic simulation studies.

Numerous malignancies, including breast cancer, non-small cell lung cancer, and chronic myeloid leukemia, are brought on by aberrant tyrosine kinase signaling. Since the current chemotherapeutic medicines are toxic, there is a great need and demand from cancer patients to find novel chemicals that are toxic-free or have low toxicity and that can kill tumor cells and stop their growth. This work describes the in-silico examination of substances from the drug bank as EGFR inhibitors. Firstly, drug-bank was screened using the pharmacophore technique to select the ligands and Erlotinib (DB00530) was used as matrix compound. The selected ligands were screened using ADMET and the hit compounds were subjected to docking. The lead compound from the docking was subjected to DFT and MD simulation study. Using the pharmacophore technique, 23 compounds were found through virtual drug bank screening. One hit molecule from the ADMET prediction was the subject of docking study. According to the findings, DB03365 molecule fits to the EGFR active site by several hydrogen bonding interactions with amino acids. Furthermore, DFT analysis revealed high reactivity for DB03365 compound in the binding pocket of the target protein, based on ELUMO, EHOMO and band energy gap. Furthermore, MD simulations for 100 ns revealed that the ligand interactions with the residues of EGFR protein were part of the essential residues for structural stability and functionality. However, DB03365 was a promising lead molecule that outperformed the reference compound in terms of performance and in-vitro and in-vivo experiments needs to validate the study.Communicated by Ramaswamy H. Sarma.

Computational evaluation of quinones of Nigella sativa L. as potential inhibitor of dengue virus NS5 methyltransferase.

Aedes aegypti is the primary vector for the transmission of the dengue virus, which causes dengue fever, dengue hemorrhagic illness and dengue shock syndrome. There is now no antiviral medication available to treat DENV, which kills thousands of people each year and infects millions of individuals. A possible target for the creation of fresh and efficient dengue treatments is the DENV-3 NS5 MTase. So, Nigella sativa quinones were examined using in silico methods to find natural anti-DENV compounds. The in silico docking was conducted utilising the Discovery Studio software on the quinones of N. sativa and the active site of the target protein DENV-3 NS5 MTase. In addition, the druggability and pharmacokinetics of the lead compound were assessed. Dithymoquinone was comparable to the reference compound in terms of its ability to bind to the active site of target protein. Dithymoquinone met the requirements for drug likeness and Lipinski's principles, as demonstrated by the ADMET analysis and drug likeness results. The current study indicated that the dithymoquinone from N. sativa had anti-DENV activity, suggesting further drug development and dengue treatment optimisation.Communicated by Ramaswamy H. Sarma.

Real-World Impact of SABR on Stage I Non-Small-Cell Lung Cancer Outcomes at a Scottish Cancer Centre.

INTRODUCTION: Stereotactic ablative body radiotherapy (SABR) offers patients with stage I non-small-cell lung cancer (NSCLC) a safe, effective radical therapy option. The impact of introducing SABR at a Scottish regional cancer centre was studied. METHODS: The Edinburgh Cancer Centre Lung Cancer Database was assessed. Treatment patterns and outcomes were compared across treatment groups (no radical therapy (NRT), conventional radical radiotherapy (CRRT), SABR and surgery) and across three time periods reflecting the availability of SABR (A, January 2012/2013 (pre-SABR); B, 2014/2016 (introduction of SABR); C, 2017/2019, (SABR established)). RESULTS: 1143 patients with stage I NSCLC were identified. Treatment was NRT in 361 (32%), CRRT in 182 (16%), SABR in 132 (12%) and surgery in 468 (41%) patients. Age, performance status, and comorbidities correlated with treatment choice. The median survival increased from 32.5 months in time period A to 38.8 months in period B to 48.8 months in time period C. The greatest improvement in survival was seen in patients treated with surgery between time periods A and C (HR 0.69 (95% CI 0.56-0.86), p < 0.001). The proportion of patients receiving a radical therapy rose between time periods A and C in younger (age ≤ 65, 65-74 and 75-84 years), fitter (PS 0 and 1), and less comorbid patients (CCI 0 and 1-2), but fell in other patient groups. CONCLUSIONS: The introduction and establishment of SABR for stage I NSCLC has improved survival outcomes in Southeast Scotland. Increasing SABR utilisation appears to have enhanced the selection of surgical patients and increased the proportion of patients receiving a radical therapy.

Pharmacophore-based virtual screening and in-silico study of natural products as potential DENV-2 RdRp inhibitors.

Dengue fever is a significant public health concern throughout the world, causing an estimated 500,000 hospitalizations and 20,000 deaths each year, despite the lack of effective therapies. The DENV-2 RdRp has been identified as a potential target for the development of new and effective dengue therapies. This research's primary objective was to discover an anti-DENV inhibitor using in silico ligand- and structure-based approaches. To begin, a ligand-based pharmacophore model was developed, and 130 distinct natural products (NPs) were screened. Docking of the pharmacophore-matched compounds were performed to the active site of DENV-2 RdRp protease . Eleven compounds were identified as potential DENV-2 RdRp inhibitors based on docking energy and binding interactions. ADMET and drug-likeness were done to predict their pharmacologic, pharmacokinetic, and drug-likeproperties . Compounds ranked highest in terms of pharmacokinetics and drug-like appearances were then subjected to additional toxicity testing to determine the leading compound. Additionally, MD simulation of the lead compound was performed to confirm the docked complex's stability and the binding site determined by docking. As a result, the lead compound (compound-108) demonstrated an excellent match to the pharmacophore, a strong binding contact and affinity for the RdRp enzyme, favourable pharmacokinetics, and drug-like characteristics. In summary, the lead compound identified in this study could be a possible DENV-2 RdRp inhibitor that may be further studied on in vitro and in vivo models to develop as a drug candidate.Communicated by Ramaswamy H. Sarma.

Hypoalbuminaemia as a Prognostic Biomarker of First-Line Treatment Resistance in Metastatic Non-small Cell Lung Cancer.

Introduction: Despite significant advances in systemic anticancer therapy (SACT) for non-small cell lung cancer (NSCLC), many patients still fail to respond to treatment or develop treatment resistance. Albumin, a biomarker of systemic inflammation and malnutrition, predicts survival in many cancers. We evaluated the prognostic significance of albumin in patients receiving first-line targeted therapy or immunotherapy-based SACT for metastatic NSCLC. Methods: All patients treated with first-line targeted therapy or immunotherapy-based SACT for metastatic NSCLC at a regional Scottish cancer centre were identified. Serum albumin at pre-treatment, after 12-weeks of treatment, and at the time of progressive disease were recorded. The relationship between albumin (≥ 35g/L v <35g/L) and overall survival (OS) was examined. Results: Data were available for 389 patients of both targeted therapy cohort (n = 159) and immunotherapy-based therapy cohort (n = 230). Pre-treatment albumin was predictive of OS in each cohort at HR1.82 (95%CI 1.23-2.7) (p =0.003) and HR2.55 (95%CI 1.78-3.65) (p < 0.001), respectively. Pre-treatment albumin <35 g/L was associated with a significantly higher relative risk of death within 12 weeks in each cohort at RR9.58 (95%CI 2.20-41.72, p = 0.003) and RR3.60 (95%CI 1.74-6.57, p < 0.001), respectively. The 12-week albumin was predictive of OS in each cohort at HR1.88 (95%CI 1.86-4.46) (p < 0.001) and HR2.67 (95%CI 1.74-4.08) (p < 0.001), respectively. 46 out of 133 (35%) evaluable patients treated with targeted therapy and 43 out of 169 (25%) treated with immunotherapy-based therapy crossed over albumin prognostic groups between pre-treatment and 12-week. The prognostic value of 12-week albumin was independent of pre-treatment albumin status. A majority of patients had albumin <35g/L at the time of progressive disease when it was also predictive of survival following progressive disease at HR2.48 (95%CI 1.61-3.82) (p < 0.001) and HR2.87 (95%CI 1.91-4.31) (p < 0.001) respectively). Conclusions: Albumin is a reliable prognostic factor in patients with metastatic NSCLC, predicting survival independent of the class of drug treatment at various time points during the patient journey. Tracking albumin concentrations during systemic therapy may indicate disease activity or treatment response over time.

Accelerated hypo-fractionated radiotherapy for non small cell lung cancer: results from 4 UK centres.

BACKGROUND AND PURPOSE: A variety of radiotherapy fractionations are used as potentially curative treatments for non-small cell lung cancer. In the UK, 55 Gy in 20 fractions over 4 weeks (55/20) is the most commonly used fractionation schedule, though it has not been validated in randomized phase III trials. This audit pooled together existing data from 4 UK centres to produce the largest published series for this schedule. MATERIALS AND METHODS: 4 UK centres contributed data (Cambridge, Cardiff, Glasgow and Sheffield). Case notes and radiotherapy records of radically treated patients between 1999 and 2007 were retrospectively reviewed. Basic patient demographics, tumour characteristics, radiotherapy and survival data were collected and analysed. RESULTS: 609 patients were identified of whom 98% received the prescribed dose of 55/20. The median age was 71.3 years, 62% were male. 90% had histologically confirmed NSCLC, 49% had stage I disease. 27% had received chemotherapy (concurrent or sequential) with their radiotherapy. The median overall survival from time of diagnosis was 24.0 months and 2 year overall survival was 50%. CONCLUSION: These data show respectable results for patients treated with accelerated hypo-fractionated radiotherapy for NSCLC with outcomes comparable to those reported for similar schedules and represent the largest published series to date for 55/20 regime.