Antimicrobial Activity of Nano-encapsulated Salvia Officinalis against Methicillin-Resistant Staphylococcus aureus and Acinetobacter Baumannii

Chorr, Bakary and Kimotho, James and Kangogo, Mourine (2026) Antimicrobial Activity of Nano-encapsulated Salvia Officinalis against Methicillin-Resistant Staphylococcus aureus and Acinetobacter Baumannii. World's Veterinary Journal. 418 - 435. ISSN 23224568

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Abstract

Antimicrobial resistance represents a global health burden requiring innovative therapeutic strategies. The antibacterial properties of Salvia officinalis (S. officinalis) are attributed to its bioactive compounds. The present study aimed to investigate the antimicrobial activity of nano-encapsulated S. officinalis leaf extract against methicillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter baumannii (A. baumannii). The crude extract of S. officinalis was subjected to methanolic extraction, and the resulting methanolic fraction was analyzed through phytochemical screening. Phytocompounds were identified using gas chromatography-mass spectrometry (GC-MS), and their potential mechanisms of action were evaluated in silico. The S. officinalis extract was nano-formulated using chitosan and characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and UV-visible spectroscopy. Antibacterial activity of the nano-formulation against MRSA and A. baumannii was assessed using agar well diffusion, broth microdilution, and minimum bactericidal concentration analysis. Qualitative phytochemical analysis revealed the presence of flavonoids, alkaloids, tannins, saponins, and terpenoids. The GC-MS analysis demonstrated 15 peaks, representing 14 distinct compounds, with one compound (3,7,11,15-tetramethyl-2-hexadecen-1-ol) eluting at two retention times. Chitosan nanoparticle formation was confirmed by an absorption peak near 290 nm. The functional groups of chitosan nanoparticles included hydroxyl (-OH) and amide (-NH₂) groups, along with Câ��H, Câ��N, Câ��O, and P=O stretching. The SEM imaging exhibited relatively homogeneous, well-dispersed, spherical nanoparticles. The antimicrobial efficacy of S. officinalis chitosan nanoparticles was concentration-dependent, reaching maximum inhibition zones of 21 ± 0.5 mm against MRSA and 17 ± 1.5 mm against A. baumannii at 500 µg/mL. Additionally, susceptibility testing revealed minimum inhibitory concentrations of 62.5 µg/mL and 125 µg/mL, and minimum bactericidal concentrations of 125 µg/mL and 500 µg/mL against MRSA and A. baumannii, respectively. Molecular docking analysis indicated that phytocompounds within the methanolic extract exhibited binding affinity toward penicillin-binding protein 2a (PBP2a) and the carbapenem-associated outer membrane protein (CarO). The interactions between the phytochemicals and protein targets indicated that binding to catalytic sites could inhibit the function of these resistance-associated proteins, potentially reducing antibiotic degradation. The biosynthesized S. officinalis chitosan nanoparticles exhibited strong antimicrobial activity against multidrug-resistant bacterial isolates, supporting their potential as antimicrobial agents. © The Author(s) 2026 CC BY Open Access: This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/.

Item Type:	Article
Keywords:	Acinetobacter baumannii; Antimicrobial resistance; Methicillin-resistant Staphylococcus aureus; Nanoparticle; Salvia officinalis
Subjects:	S Agriculture > SF Animal culture
Divisions:	World's Veterinary Journal (WVJ)
Page Range:	418 - 435
Journal or Publication Title:	World's Veterinary Journal
Journal Index:	Scopus
Volume:	16
Number:	2
Publisher:	Scienceline Publication
Identification Number:	https://doi.org/10.54203/scil.2026.wvj40
ISSN:	23224568
Depositing User:	Dr. Alireza Sadeghi
URI:	https://eprints.science-line.com/id/eprint/1690

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