Antibacterial Efficacy of Endophytic Bacterial Fractions from Basil Leaves (Ocimum sanctum) against Streptococcus mutans and Pseudomonas aeruginosa
DOI:
https://doi.org/10.35790/eg.v14i2.67417Keywords:
antibacterial activity; Bacillus species; endophytic bacteria; Ocimum sanctumAbstract
Abstract: Endophytic bacteria in Ocimum sanctum are promising antimicrobial sources, yet the localized efficacy of their intracellular versus extracellular metabolites against oral pathogens remains underexplored. This study compared the cell mass (CM) and cell-free supernatant (CFS) fractions of six Bacillus sp. isolates (EO1–EO6) against Streptococcus mutans and Pseudomonas aeruginosa. Statistical analysis (Two-Way ANOVA, Tukey’s HSD, p < 0.05) revealed that the antibacterial efficacy is highly strain-dependent and target-specific. Against the Gram-positive S. mutans, the CFS of isolates EO5 and EO6 demonstrated significantly superior inhibition (5.69 ± 0.83 mm and 5.54 ± 0.55 mm, respectively) compared to their CM fractions. Conversely, all fractions exhibited uniformly weak and non-significant inhibition against the Gram-negative P. aeruginosa. In conclusion, Bacillus sp. CFS effectively inhibits S. mutans through robust extracellular secretion, suggesting strong potential for development into preventative oral therapeutics.
Keywords: antibacterial activity; Bacillus species; endophytic bacteria; Ocimum sanctum
References
1. Dharsono HDA, Putri SA, Kurnia D, Dudi D, Satari MH. Ocimum Species: A review on chemical constituents and antibacterial activity. Molecules. 2022;27(19):1–23. Doi: https://doi.org/10.3390/molecules27196350
2. Satwika D, Amarantini C, Wibawa CS. Phytochemical analysis and antibacterial activity of basil (Ocimum basilicum L.) essential oil and leaves ethanolic extract. Makara Journal of Health Research. 2024;XXX(XXX):1-5. Available from: https://repository.ukdw.ac.id/9443/
3. Bagnazari M, Alymanesh MR, Ghanbari F, Azizi A. Isolated endophytic bacteria promoted growth, essential oil content, and antioxidant activity in Basil (Ocimum basilicum L.). Sci Rep. 2025;15(1):1–13. Available from: https://www.nature.com/articles/s41598-025-20218-z
4. Long XN, Zhang XK, Wu Y, Tang SS, Zheng TX, Chen D, et al. Diversity and functional roles of endophytic and rhizospheric microorganisms in Ophioglossum vulgatum L.: implications for bioactive compound synthesis. Frontiers in Microbiology. 2025;16(July):1–15. Doi: https://doi.org/10.3389/fmicb.2025.1618667
5. Singarapalle S, Tulasi P, Ishwarya VVS, Nagendla SL, Devasani JR, Guntuku GS, et al. Bioactive compound from Micrococcus luteus associated with Datura stramonium L. seeds. Indian Journal of Chemistry (IJC). 2025;64(6):634–9. Doi: https://doi.org/10.56042/ijc.v64i6.16839
6. Kim H, Han CY, Eun SH, Kim MG, Im AR, Lee B. Inhibitory effects of Bacillus velezensis ID-A01 supernatant against Streptococcus mutans. BMC Microbiology. 2023;23(1):1–8. Available from: https:// link.springer.com/article/10.1186/s12866-023-03114-2
7. Rudzite M, Subramoni S, Endres RG, Filloux A. Effectiveness of Pseudomonas aeruginosa type VI secretion system relies on toxin potency and type IV pili-dependent interaction. PLoS Pathog. 2023;19(5): e1011428. Doi: http://dx.doi.org/10.1371/journal.ppat.1011428
8. Sharaf MH, Abdelaziz AM, Kalaba MH, Radwan AA, Hashem AH. Antimicrobial, antioxidant, cytotoxic activities and phytochemical analysis of fungal endophytes isolated from Ocimum basilicum. Applied Biochemistry and Biotechnology. 2022;194(3):1271–89. Doi: https://doi.org/10.1007/s12010-021-03702-w
9. Torshabi M, Bardouni MM, Hashemi A. Evaluation of antioxidant and antibacterial effects of lyophilized cell-free probiotic supernatants of three Lactobacillus spp. and their cytocompatibility against periodontal ligament stem cells. Iran J Pharm Res. 2023;22(1):e136438. Doi: https://doi.org/10.5812/ijpr-136438
10. Ohshima T, Kawai T, Maeda N. Bacterial cell-free probiotics using effective substances produced by probiotic bacteria, for application in the oral cavity. Prebiotics and Probiotics - Potential Benefits in Nutrition and Health. 2020;1–11. Doi: https://doi.org/10.5772/intechopen.89008
11. Cappuccino. JG, Sherman N. New features make the micro Lab more clinical application Gram staining: The First. Microbiology: A Laboratory Manual (10th ed). London: Pearson; 2014. p. 97–153.
12. Schuetz AN, Ferrell A, Hindler JA, Humphries R, Bobenchik AM. Overview of changes in the clinical and laboratory standards institute performance standards for antimicrobial susceptibility testing: M100 32nd and 33rd editions. Journal of Clinical Microbiology. 2025;63(9):1–15. Doi: https://doi.org/10.1128/jcm.01623-23
13. Davis WW, Stout TR. Disc plate method of microbiological antibiotic assay. II. Novel procedure offering improved accuracy. Appl Microbiol. 1971;22(4):666–70. Doi: https://doi.org/10.1128/am.22.4.666-670.1971
14. Sahu PK, Singh S, Singh UB, Chakdar H, Sharma PK, Sarma BK, et al. Inter-genera colonization of Ocimum tenuiflorum endophytes in Tomato and their complementary effects on Na+/K+ balance, oxidative stress regulation, and root architecture under elevated soil salinity. Front Microbiol. 2021;12(October):1–17. Doi: https://doi.org/10.3389/fmicb.2021.744733
15. Gupta S, Pandey S, Sharma S. Decoding the plant growth promotion and antagonistic potential of bacterial endophytes from Ocimum sanctum Linn. against root rot pathogen Fusarium oxysporum in Pisum sativum. Front Plant Sci. 2022;13(February):1–19. Doi: https://doi.org/10.3389/fpls.2022.813686
16. Ikryannikova LN, Kurbatov LK, Gorokhovets NV, Zamyatnin AA. Contact-dependent growth inhibition in bacteria: Do not get too close! International Journal of Molecular Sciences. 2020;21(21):1–16. Doi: https://doi.org/10.3390/ijms21217990
17. García-Bayona L, Guo MS, Laub MT. Contact-dependent killing by Caulobacter crescentus via cell surface-associated, glycine zipper proteins. eLife. 2017;6:1–26. Doi: https://doi.org/10.7554/eLife.24869
18. Ajuna HB, Lim HI, Moon JH, Won SJ, Choub V, Choi SI, et al. The prospect of antimicrobial peptides from Bacillus species with biological control potential against insect pests and diseases of economic importance in agriculture, forestry and fruit tree production. Biotechnology and Biotechnological Equipment. 2024;38(1). Doi https://doi.org/10.1080/13102818.2024.2312115
19. Vaishnavi T. Marine-derived Bacillus biosurfactants as potential antibacterial and antibiofilm agents against oral pathogens. Microorganisms. 2026;14(3):573. Doi; https://doi.org/10.3390/microorganisms14030573
20. Galinier A, Delan-Forino C, Foulquier E, Lakhal H, Pompeo F. Recent advances in peptidoglycan synthesis and regulation in bacteria. Biomolecules. 2023;13(5):720. Doi: https://doi.org/10.3390/biom13050720
21. Elfadadny A, Ragab RF, AlHarbi M, Badshah F, Ibáñez-Arancibia E, Farag A, et al. Antimicrobial resistance of Pseudomonas aeruginosa: navigating clinical impacts, current resistance trends, and innovations in breaking therapies. Frontiers in Microbiology. 2024;15(April):1–20. Doi: https://doi.org/10.3389/fmicb.2024.1374466
22. Amisano F, Mercuri P, Fanara S, Verlaine O, Motte P, Frère JM, et al. Outer membrane permeability of Pseudomonas aeruginosa through β-lactams: new evidence on the role of OprD and OpdP porins in antibiotic resistance . Microbiology Spectrum. 2025;13(4). Doi: https://doi.org/10.1128/spectrum.00495-24
23. Mazza L, Bory A, Luscher A, Kloehn J, Wolfender JL, van Delden C, et al. Multidrug efflux pumps of Pseudomonas aeruginosa show selectivity for their natural substrates. Front Microbiol. 2024;15(January):1–17. Doi: https://doi.org/10.3389/fmicb.2024.1512472
24. Abdelmalek S, Hajar M, Salah L, Abdel-Halim H. In silico screening and experimental validation of novel MexAB–OprM efflux pump inhibitors of Pseudomonas aeruginosa. Microbial Drug Resistance. 2024;30(2):73–81. Doi: https://doi.org/10.1089/mdr.2023.0126
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2026 Diannita Harahap, Rizkina Zurriani ZN, Arif Sardi, Uce Karlina
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
COPYRIGHT
Authors who publish with this journal agree to the following terms:
Authors hold their copyright and grant this journal the privilege of first publication, with the work simultaneously licensed under a Creative Commons Attribution License that permits others to impart the work with an acknowledgment of the work's origin and initial publication by this journal.
Authors can enter into separate or additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (for example, post it to an institutional repository or publish it in a book), with an acknowledgment of its underlying publication in this journal.
Authors are permitted and encouraged to post their work online (for example, in institutional repositories or on their website) as it can lead to productive exchanges, as well as earlier and greater citation of the published work (See The Effect of Open Access).
