eng Oriental Scientific Publishing Company Biomedical and Pharmacology Journal 0974-6242 2022-03-31 15 1 179 186 10.13005/bpj/2353 43602 article Mazlin Mohideen 1 Nik Nur Syahidatul Jannah Mahadi 1 Nur Aina Nabilah Suhaimi 1 Nur Azzalia Kamaruzaman 2 Ahmad Yasser Hamdi Nor Azlan 1 Faculty of Pharmacy and Health Sciences, Universiti Kuala Lumpur Royal College of Medicine Perak, Ipoh, Perak, Malaysia National Poison Centre, Universiti Sains Malaysia, 11800 Minden, Pulau Pinang, Malaysia Background: Citrus hystrix (C. hystrix), locally known as ‘limau purut,’ is Malaysia’s major commercial fruit harvest. Besides being a common ingredient in Asian cuisines, the extracted essential oil has diverse applications. The essential oil can be extracted from peels or leaves, which could give strong aromatic properties. Objective: The main purpose of this study is to evaluate the antibacterial activity of C. hystrix essential oil by using disc diffusion method. Materials and Methods: C. hystrix essential oil was extracted from the peels using the Clevenger apparatus of hydro-distillation method. The antibacterial activity of essential oil was evaluated by agar disc diffusion method against four strains of bacteria: two Gram-positive bacteria (Staphylococcus aureus ATCC 25923 and Staphylococcus epidermidis ATCC 12228) and two Gram-negative bacteria (Escherichia coli ATCC 25922 and Shigella dysenteriae ATCC 13313). Each assay was done in triplicates. In this research, positive controls gentamicin and streptomycin were used as indicators to prove the research’s validity. Results: The Gram-positive bacteria were more susceptible to the essential oil (average zone of inhibition diameter; S. aureus = 19.3 ± 1.5 mm and S. epidermidis = 19.3.0 ± 0.6 mm) as compared to the Gram-negative bacteria (average zone of inhibition diameter; E. coli = 8.3 ± 0.6 mm and S. dysenteriae = 11.7 ± 0.6 mm).  Gentamicin was recorded to be most effective against all tested bacteria (more than 15 mm zone of inhibition diameter). However, only S. epidermidis showed resistance to streptomycin. Conclusion: C. hystrix essential oil was found to possess antibacterial activity. Thus, these findings indicated that C. hystrix essential oil could be developed as an antibacterial agent in various applications. https://biomedpharmajournal.org/vol15no1/antibacterial-properties-of-essential-oil-extracted-from-kaffir-lime-citrus-hystrix-peel/ Antibacterial Citrus Hystrix Peel  Disc Diffusion Essential Oil Hydro-Distillation