Antibacterial Activity Test of Sunkist Orange (Citrus sinensis) Peel Ethanol Extract against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa Using the Disc Diffusion Method
DOI:
https://doi.org/10.62710/4dphvt17Keywords:
Citrus sinensis, ethanol extract, antibacterial activity, disc diffusion, orange peelAbstract
Infections caused by Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa remain a major public health burden, and the growing prevalence of antibiotic resistance has driven the search for natural antibacterial alternatives. Sunkist orange (Citrus sinensis) peel, an abundant agro-industrial waste, contains bioactive compounds such as flavonoids, limonene, tannins, and essential oils with reported antibacterial potential. This study aimed to evaluate the antibacterial activity of ethanol extract of Sunkist orange peel against the three bacteria using the disc diffusion method. A true experimental laboratory design with a completely randomized post-test only control group design was applied. The extract was obtained through maceration with 96% ethanol and tested at concentrations of 25%, 50%, 75%, and 100%, with Ciprofloxacin as positive control and distilled water as negative control, each in triplicate. Inhibition zone diameters were analyzed descriptively and inferentially using Shapiro-Wilk, Levene's Test, Kruskal-Wallis, and Mann-Whitney U post hoc tests. Results showed that the extract produced inhibition zones at all concentrations, increasing in a dose-dependent manner. The highest mean inhibition was observed against E. coli (17.28 mm at 100%), followed by P. aeruginosa (10.73 mm) and S. aureus (9.92 mm). Kruskal-Wallis tests revealed significant differences among concentration groups for all three bacteria (p < 0.05), confirming a genuine concentration-dependent effect, although all extract concentrations remained significantly weaker than the positive control. These findings support the potential of Sunkist orange peel as a natural antibacterial agent, though further purification and phytochemical quantification are recommended.
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References
Amiliah, A., Nurhamidah, N., & Handayani, D. (2021). Aktivitas antibakteri kulit buah jeruk kalamansi (Citrofortunella microcarpa) terhadap bakteri Staphylococcus aureus dan Escherichia coli. ALOTROP: Jurnal Pendidikan dan Ilmu Kimia, 5(1), 92–105. https://doi.org/10.33369/atp.v5i1.16493
Bouyahya, A., El Omari, N., El Menyiy, N., Guaouguaou, F.-E., Balahbib, A., & Taha, D. (2023). Essential oils from Citrus sinensis: Chemical composition and antibacterial activity. Heliyon, 9(2), e12964. https://doi.org/10.1016/j.heliyon.2023.e12964
Davis, W. W., & Stout, T. R. (1971). Disc plate method of microbiological antibiotic assay: I. Factors influencing variability and error. Applied Microbiology, 22(4), 659–665. https://doi.org/10.1128/am.22.4.659-665.1971
Eladl, O., Hafez, E. E., Hashem, A. M., & Shata, M. A. (2025). Biophysical and transcriptomic characterization of LL-37-derived antimicrobial peptide targeting multidrug-resistant Escherichia coli and ESKAPE pathogens. Scientific Reports, 15(1), 36126. https://doi.org/10.1038/s41598-025-22890-7
Gupta, A., Jeyakumar, E., & Lawrence, R. (2021). Strategic approach of multifaceted antibacterial mechanism of limonene traced in Escherichia coli. Scientific Reports, 11, 13816. https://doi.org/10.1038/s41598-021-92843-3
Hamers, R. L. (2024). Antimicrobial resistance among common bacterial pathogens in Indonesia: A systematic review. Lancet Regional Health – Southeast Asia, 26, 100414. https://doi.org/10.1016/j.lansea.2024.100414
Jubair, N., Rajagopal, M., Chinnappan, S., Abdullah, N. B., & Fatima, A. (2021). Review on the antibacterial mechanism of plant-derived compounds against multidrug-resistant bacteria (MDR). Evidence-Based Complementary and Alternative Medicine, 2021, 3663315. https://doi.org/10.1155/2021/3663315
Musyaffa, M. S. I., Yudistira, N., Rahman, M. A., & Batoro, J. (2023). IndoHerb: Indonesia medicinal plants recognition using transfer learning and deep learning. arXiv preprint. https://arxiv.org/abs/2308.01604v2
Oikeh, E. I., Oviasogie, F. E., & Omoregie, E. S. (2020). Quantitative phytochemical analysis and antimicrobial activities of fresh and dry ethanol extracts of Citrus sinensis (L.) Osbeck (sweet orange) peels. Clinical Phytoscience, 6, 46. https://doi.org/10.1186/s40816-020-00193-w
Pang, Z., Raudonis, R., Glick, B. R., Lin, T.-J., & Cheng, Z. (2019). Antibiotic resistance in Pseudomonas aeruginosa: Mechanisms and alternative therapeutic strategies. Biotechnology Advances, 37(1), 177–192. https://doi.org/10.1016/j.biotechadv.2018.11.013
Qaralleh, H. A., Al-Limoun, M. O., Khlaifat, A., Al-Tawarah, N., & Abu-Harirah, H. A. (2021). Antibacterial and antibiofilm activities of a traditional herbal formula against respiratory infection causing bacteria. arXiv preprint. https://arxiv.org/abs/2102.04301v1
Saxena, M., Singh, D., & Tiwari, S. (2021). Phytochemical screening and antibacterial activity of Citrus sinensis peel extract. Journal of Applied Biology & Biotechnology, 9(1), 45–49. https://doi.org/10.7324/JABB.2021.9110
Sugiharto, R., Prasetya, A., & Wibowo, H. (2022). Phytochemical content and antioxidant activity of sweet orange (Citrus sinensis) peel extract using ethanol as solvent. IOP Conference Series: Earth and Environmental Science, 979, 012029. https://doi.org/10.1088/1755-1315/979/1/012029
Usamo, F. B., et al. (2024). In vitro antioxidant and antibacterial activities of Ajuga integrifolia leaf extracts obtained with different solvents. BMC Complementary Medicine and Therapies, 24(1), 368. https://doi.org/10.1186/s12906-024-04668-y
Weezenbeek, K. V., et al. (2024). WHO global research priorities for antimicrobial resistance in human health. Lancet Microbe, 5(11), 100902. https://doi.org/10.1016/S2666-5247(24)00134-4
World Health Organization. (2024). Antimicrobial resistance [Fact sheet]. https://www.who.int/news-room/fact-sheets/detail/antimicrobial-resistance
Yan, Y., Xia, X., Fatima, A., Zhang, L., Yuan, G., Lian, F., & Wang, Y. (2024). Antibacterial activity and mechanisms of plant flavonoids against gram-negative bacteria based on the antibacterial statistical model. Pharmaceuticals, 17(3), 292. https://doi.org/10.3390/ph17030292
