en عمومى General پژوهشي orginal article <span style="line-height:1;"><span style="font-size:16px;"><span style="font-family:Times New Roman;"><b>Background</b> Antibiotic resistance among pathogenic bacteria represents a critical global health concern, underscoring the urgent need for novel antibacterial agents. The compound (5aR,11aS,11bR)-1,2,3,5a,11a,11b-hexahydrospiro[benzo[f]pyrrolo[2,1-a]isoindole-5,2&#39;-indene]-1&#39;,3&#39;,6,11-tetraone (compound 6) and its derivatives constitute a new class of potential antibacterial agents. This study aimed to evaluate the antibacterial activity of the synthesized compound 6 against resistant bacterial strains.<br> <b>Methods</b> Compound 6 was synthesized via a one-pot 1,3-dipolar cycloaddition reaction involving azomethine ylide, generated in situ from ninhydrin, 1,4-naphthoquinone, and proline, using ethanol as an environmentally friendly solvent. The molecular structure and functional groups of the synthesized compound were characterized by Fourier-transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance (^1H NMR) analysis. Antibacterial activity was evaluated by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against standard strains of Escherichia coli and Staphylococcus aureus using broth microdilution and agar culture methods.<br> <b>Results</b> FT-IR and ^1H NMR spectral analyses confirmed the purity and regioselectivity of the synthesized product. Antibacterial testing revealed that compound 6 exhibited MIC and MBC values of 2.5 &mu;g/mL for both S. aureus and E. coli. The MIC and MBC values of the standard antibiotics were 0.3 &mu;g/mL and 1.2 &mu;g/mL for gentamicin (against E. coli), and 1 &mu;g/mL for vancomycin (against S. aureus).<br> <b>Conclusion </b>Compound 6 demonstrated notable antibacterial activity against Escherichia coli and Staphylococcus aureus, with MIC and MBC values comparable to those of standard antibiotics. The compound exhibited a stronger bactericidal effect against the Gram-positive bacterium S. aureus than against the Gram-negative E. coli. Further in vitro and in vivo studies are warranted to evaluate its safety profile and potential therapeutic applications.</span></span></span><br> &nbsp; 1,3 dipole ring formation, Anti-Bacterial agents, Escherichia coli, Pyrrolizidine, Staphylococcus aureus 383 389 http://ijrabms.umsu.ac.ir/browse.php?a_code=A-10-638-1&slc_lang=en&sid=1 Arian Saidi arian.saidi.us@gmail.com 10031947532846005579 10031947532846005579 No School of Pharmacy, Urmia University of Medical Sciences, Urmia, Iran. Reza Akbari akbarireza43@yahoo.com 10031947532846005580 10031947532846005580 No Department of Microbiology and Virology, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran Mehri Kouhkan kouhkan.m@umsu.ac.ir 10031947532846005581 10031947532846005581 Yes Department of Medicinal Chemistry, School of Pharmacy, Urmia University of Medical Sciences, Urmia, Iran