Rajendran Thirugnanasambandam

Acinetobacter baumannii (A. baumannii) is a notorious nosocomial pathogen known for its ability to form biofilms, which contribute to its high resistance to conventional antibiotics and immune clearance. This study aimed to evaluate the antibiofilm activity of ethanolic extracts of Sargassum wightii against multidrug-resistant (MDR) A. baumannii and to identify potential bioactive compounds using gas chromatography–mass spectrometry (GC-MS) and molecular docking. The ethanolic extract exhibited minimum inhibitory concentration (MIC) values ranging from 70 to 100 µg/mL against A. baumannii. Moreover, the extract inhibited biofilm formation in a concentration-dependent manner, which was further confirmed by epifluorescence microscopy, revealing a marked reduction in biofilm biomass compared with the untreated control. GC-MS analysis of the ethanolic extract of S. wightii identified 10 major compounds. Molecular docking was performed to investigate the interaction of the identified bioactive compounds with the biofilm response regulator protein BfmR of A. baumannii. Among the identified compounds, three molecules (CAS No. 002302-12-7, 015120-94-2, and 146397-91-3) exhibited the highest binding affinity toward BfmR. Ligands CAS No. 002302-12-7 and CAS No. 146397-91-3 showed binding energies (∆Gbind) of −42.26 and −50.49 kcal/mol, respectively, while CAS No. 015120-94-2 achieved the lowest Glide score (−4.067 kcal/mol). These compounds demonstrated promising interactions with BfmR and may serve as a putative molecular target potentially associated with the observed antibiofilm activity in A. baumannii. Overall, the findings indicate that S. wightii possesses significant antibiofilm activity against A. baumannii, with its bioactive constituents exhibiting promising drug-likeness and pharmacokinetic properties, demanding further experimental validation.

This study utilised computational analysis to investigate the therapeutic potential of phloroglucinol against rheumatoid arthritis (RA). The Differentially expressed genes were identified from the GEO dataset GSE1919 and RA-associated targets were retrieved from the Comparative Toxicogenomics Database (CTD). By comparing these datasets, we identified 17 overlapping targets using a Venn diagram. Then, the top five genes are identified using Cytoscape and CytoHubba plugin. Gene Ontology and KEGG pathway enrichment analyses revealed involvement of these targets in inflammatory signalling. The ADME analysis through the QikProp module demonstrated favourable pharmacokinetic properties, including a molecular weight of 126.112 Da, QPlogPo/w of -0.020, oral bioavailability of 70.508% and no violation of Lipinski's Rule of Five. The molecular docking analysis indicated moderate binding affinities with key inflammatory proteins such as IL6 (-3.583) IL-10 (-2.735), IL-1β (-3.764), ICAM1 (-2.890), and TNF-α. (-4.568). The phloroglucinol-TNF-α complex was subjected to 500 ns molecular dynamics simulation, which confirmed structural stability as evidenced by RMSD values and preserved secondary structure throughout the simulation. These findings identify phloroglucinol as a promising natural small-molecule with TNF-α as its primary molecular target.

Metal nanoparticles, such as gold nanoparticles, silver nanoparticles, etc., have many benefits and have been in use for a very long time. Nevertheless, a number of concerns have been raised about the environmental impact and the possibility of exposure to various living systems at the moment. Thus, in this study, silver nanoparticles were synthesized by using plant gum from Bauhinia purpurea and characterization was done using UV—Visible Spectroscopy, Scanning Electron Microscopy, X—ray Diffraction, etc. To determine the accumulation and toxic effects caused by the nanoparticles, Eudrilus eugeniae, Danio rerio, and their embryos were exposed to the synthesized silver nanoparticles and evaluated using microscopic observation, histology, and Inductively Coupled Plasma Optical Emission Spectrometry (ICP—OES).

Nanoparticles are potential candidates for wastewater treatment especially for the removal of heavy metals due to their strong affinity. Many biopolymers are used as adsorbents and encapsulation of nanoparticle onto them can increase their efficiency. In this study, SPIONs, alginate, and SPIONs incorporated on alginate beads have been synthesized and characterized both microscopically and spectroscopically. These were then used for the removal of chromium metal and the percentage of removal was evaluated using a batch adsorption study. The percent removal of chromium using SPIONs, alginate and alginate–SPIONs beads were recorded to be 93%, 91% and 94%, respectively. The adsorption of chromium using SPIONs and alginate–SPIONs beads followed the Tempkin isotherm, whereas adsorption of chromium metal by alginate beads was found to be homogeneous in nature and followed the Langmuir isotherm with an R² value of 0.9784. An in-vivo study using Danio rerio as a model organism was done to examine the toxicity and the removal efficiency of the samples. It was observed that chromium water treated with alginate–SPIONs beads, which were removed after water treatment showed less damage to the fishes when compared to SPIONs and alginate beads treated with chromium water where the SPIONs and alginate beads were not removed after the treatment period.