Guru Nanak Khalsa College of Arts, Science & Commerce

Background Lower respiratory tract infections caused by Streptococcus pneumoniae, Haemophilus influenzae, Pseudomonas aeruginosa, and Staphylococcus aureus account for an estimated 2.49 million deaths annually and are increasingly complicated by multidrug-resistant (MDR) strains for which no broad-spectrum inhibitor of a conserved mechanistic target exists. Elongation Factor G (EF-G), the ribosomal GTPase encoded by the essential single-copy fusA gene, is structurally conserved across all four pathogens and constitutes an underexploited candidate for pan-bacterial inhibitor design. Methods We report an in silico structure-based screening campaign against EF-G spanning all four organisms, extended in this revision with explicit molecular dynamics (MD) validation. EF-G sequences were retrieved from NCBI and subjected to InterProScan 5 domain annotation and BLASTp selectivity screening against the human proteome. Homology models were constructed using SWISS-MODEL and validated by QMEAN Z-score and GMQE metrics. Approximately 500 phytochemicals from Dr. Duke's Database were filtered through a ten-step ADMET pipeline (SWISS-ADME; ProTox-3.0; Lipinski, Ghose, Veber, Egan, and Muegge filters), yielding ∼350 drug-like candidates that were docked against all four EF-G models using AutoDock Vina v1.1.2 via PyRx. Top-ranked complexes were further evaluated by PDBePISA thermodynamic assembly analysis and PLIP residue-level interaction profiling. To move beyond static docking scores, the lead compound (Alloalantolactone) and the fusidic acid reference were each carried forward into 100 ns all-atom explicit-solvent MD simulations (GROMACS 2024.4, AMBER99SB-ILDN/TIP3P) against all four EF-G models (eight independent 100 ns trajectories), with trajectory-based RMSD, RMSF, radius of gyration, solvent-accessible surface area, hydrogen-bonding and contact analyses, and end-state MM/GBSA and MM/PBSA binding free-energy estimation. Results InterProScan 5 returned an identical 16-entry domain profile for all four EF-G sequences, consistent with conservation of the GTPase catalytic apparatus and the absence of significant human homologues (BLASTp E-value < 0.01). Docking identified six phytochemicals — Alloalantolactone, (+)-Alantolactone, Abyssinone I, (+)-Galbacin, Abyssinone V, and Asarinin — with mean pan-bacterial AutoDock Vina scores of −8.50 to −9.28 kcal/mol, more negative than the fusidic acid reference (mean −8.00 kcal/mol); PDBePISA and PLIP analyses indicated thermodynamically plausible, geometrically defined interfaces for five of six leads at the GTPase domain I active site, distinct from the post-hydrolytic hydrophobic pocket occupied by fusidic acid. The 100 ns MD simulations showed that Alloalantolactone forms a comparatively stable complex with all four EF-G models (mean protein backbone RMSD 0.35–0.67 nm), in several cases more stable than the corresponding fusidic acid trajectories, and maintains persistent, if sparse, direct protein contacts throughout the simulated timescale. However, end-state MM/GBSA and MM/PBSA free-energy estimates did not reproduce the docking-based ranking: fusidic acid showed more negative (numerically stronger) predicted binding free energies than Alloalantolactone in all four organisms (e.g., MM/GBSA −55.9 vs. −35.4 kcal/mol for H. influenzae; −35.8 vs. −17.3 kcal/mol for P. aeruginosa), indicating that the two scoring approaches are not concordant and that Alloalantolactone’s docking-stage advantage over fusidic acid is not confirmed at the MD/end-state free-energy level. All six ADMET-screened leads satisfied Lipinski's Rule-of-Five with zero violations, achieved a bioavailability score of 0.55, and were classified as ProTox-3.0 Toxicity Class IV (LD50 300–2000 mg/kg). Conclusions Alloalantolactone and (+)-Alantolactone emerge as the most internally consistent computational leads across docking and post-docking interaction profiling (PDBePISA, PLIP). Only Alloalantolactone was additionally subjected to 100 ns MD stability and MM/GBSA/MM/PBSA free-energy analysis across all four EF-G targets; (+)-Alantolactone's dynamic and free-energy behaviour has not been evaluated and should not be assumed equivalent. Both compounds are proposed as priority candidates for experimental follow-up rather than as validated inhibitors. The MD-derived free-energy data temper rather than reinforce the pan-bacterial superiority claim suggested by docking scores alone, and the mechanistic distinction from the fusidic acid binding site should be read as a structural observation, not as demonstrated evidence of activity against fusidic acid-resistant (FusA-, FusB-, or FusE-type) strains. These findings, together with their limitations, provide a basis for advancing the sesquiterpene-lactone leads to in vitro GTPase inhibition assays and minimum inhibitory concentration testing against MDR clinical isolates, which remain necessary before any translational claim can be made.

Artemisia pallens, an aromatic and medicinal plant occasionally referred to as Davana is a member of the Asteraceae family. Understanding the physiochemical and therapeutic properties of Davana essential oil (DEO) is the major aim of this study. Essential oil from plant material was extracted using the hydro-distillation method. Examination of the phytochemical components and several plant constituents from the whole oil were detected using GC–MS analysis and some components were Isobutyl propionate, 4,5-Dimethyl-Thiazole, Ligustrazin, Endo-2-Norborneol, Tetradecanoic acid, and Octadecanoic acid. The thermal stability of the oil was tested using thermoanalytical studies such as TG–DTA and DSC. Moreover, to comprehend the biological potential of the oil antimicrobial, antituberculosis, antimalarial, antioxidant, anticancer, and antibiofilm activities were investigated essential oil was tested for antimicrobial activity against 10 bacterial and 7 fungal strains. The antimalarial potential was evaluated against Plasmodium falciparum. Cytotoxicity of the DEO was determined against MCF-7, HeLa, and CHO cell lines employing MTT assay. Meanwhile, the DPPH assay was adopted to assess antioxidant potential, and the ability to suppress biofilm formation was also assessed. The study’s findings reveal that Artemisia pallens is a reservoir of natural compounds and can be used against numerous ailments.

Multidrug-resistant bacteria are now widely recognized as a global threat and a substantial public health concern. Antimicrobial resistance (AMR) is known as a more significant threat to humanity. Multidrug-resistant (MDR)/ Extensively Drug-resistant (XDR) Mycobacterium tuberculosis (M. tb) is a prime example of AMR. Furthermore, treating MDR-TB is more challenging since it demands second-line treatments, which have severe side effects. Genomic & proteomic approaches are employed in pharmaceutical research to identify novel drug targets. A subtractive proteomics approach was applied in this study to identify promising therapeutic targets for the MDR strain M. tb CCDC5180. The subtractive proteome approach of the whole proteome of M. tb CCDC5180 showed a list of 14 essential, cytoplasmic, and unique metabolic proteins discovered to be druggable. Among these 14, only eight proteins were involved in the pathogen's virulence. Finally, two proteins, PrrA and KdpE, were identified as potential novel drug targets, and further docking of these proteins with phytochemicals resulted in two promising compounds Cepharanthine and Alianthone against these novel targets.

Tuberculosis is a serious disease that requires a greater understanding of its pathophysiology to develop effective treatment strategies. To gain a better understanding of mycobacterial physiology, researchers are focusing on the key components associated with cell wall synthesis. Although mycolic and fatty acids are the primary lipid components of the mycobacterial cell envelope, understanding the proteins involved in the lipid biosynthesis pathway may open up new avenues for fundamental research. This research included a thorough computational examination of proteins from the fatty acid biosynthesis pathways. Rv2881c and Rv2764c are essential genes for lipid synthesis. It is a potential drug target because knocking out these genes has an impact on Mtb growth. The study's findings provide researchers with specific cues and concrete information that can be applied in a variety of biotechnological applications.