Comparative Antibacterial Activity of Luteolin and Morin Against Gram-Positive Bacteria: In Vitro Evaluation and Molecular Docking Targeting Penicillin-Binding Protein 3
DOI:
https://doi.org/10.62382/xfvw4z36Keywords:
Luteolin, Morin, Cefazolin, Antibacterial, Computational, In vitroAbstract
The rising prevalence of antibacterial resistance needs the exploration of novel antibacterial drugs from natural products. Flavonoids such as Morin and Luteolin possess various pharmacological applications, their antibacterial mechanism targeting Penicillin-Binding Protein 3 (PBP3) is not appropriately addressed. This study aimed to compare the antibacterial potential and mechanism of Morin and Luteolin targeting selected strains of gram-positive bacteria and their mechanism via interaction with PBP3 computationally, which is a key enzyme linked with the biosynthesis of bacterial cell wall. Antibacterial activity was investigated against Streptococcus pneumoniae, Bacillus subtilis, and Staphylococcus aureus harnessing methods such as Kirby-Bauer disc diffusion and broth dilution. Cefazolin selected a reference standard antibiotic. Besides, Molecular docking was conducted against PBP3 harnessing PyRx 0.8 to assess binding affinity and interaction behavior. Both flavonoids showed concentration dependent antibacterial activity. Morin revealed zones of inhibition of 12 ± 0.29 mm, 10 ± 0.29 mm, and 14 ± 0.46 mm against S. pneumoniae, B. subtilis, and S. aureus, respectively. In contrast, Luteolin showed inhibition zones of 10 ± 0.32 mm, 9 ± 0.24 mm, and 11 ± 0.35 mm. Luteolin revealed lower MIC values 256–512 μg/mL than Morin 512 μg/mL against S. pneumoniae and S. aureus, while both compounds showed an MIC of 512 µg/mL against B. subtilis. Molecular docking showed favorable binding affinities for Cefazolin (-8.8 kcal/mol), followed by Luteolin (-8.1 kcal/mol), and Morin (-7.9 kcal/mol). Both flavonoids showed predicted interactions within the PBP3 active site region of the selected P. aeruginosa PBP3 structure. Morin and Luteolin revealed measurable antibacterial activity, and molecular docking suggested a potential interaction with PBP3 consistent with a possible interference with cell-wall synthesis mechanism computationally. Among the tested flavonoids, Luteolin showed superior antibacterial potency, supporting its potential as a promising natural antibacterial lead.
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Copyright (c) 2026 Majid Khan, Noman Nazir, Jamal Shahzad, Muhammad Usman Amin, Najm Ur Rahman, Ashraf Ullah Khan (Author)
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