L and Electronics Engineering, Universiti Tenaga Nasional, Kajang 43000, Malaysia; [email protected] College of Civil and Environmental Engineering, University of Technologies Sydney, Sydney, NSW 2007, Australia; [email protected] Correspondence: [email protected]: Lim, A.C.; Tang, S.G.H.; Zin, N.M.; Maisarah, A.M.; Ariffin, I.A.; Ker, P.J.; Mahlia, T.M.I. Chemical Composition, Antioxidant, Antibacterial, and Antibiofilm Activities of Backhousia citriodora Critical Oil. Molecules 2022, 27, 4895. doi.org/10.3390/ molecules27154895 Academic Editors: Alessandra Morana and Giuseppe Squillaci Received: 30 June 2022 Accepted: 26 July 2022 Published: 31 July 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.Abstract: The necessary oil of Backhousia citriodora, commonly called lemon myrtle oil, possesses numerous effective properties resulting from its richness in bioactive compounds. This study aimed to characterize the chemical profile on the essential oil isolated from leaves of Backhousia citriodora (BCEO) and its biological properties, like antioxidant, antibacterial, and antibiofilm activities. Utilizing gas chromatography ass spectrometry, 21 compounds were identified in BCEO, representing 98.50 with the total oil content. The isomers of citral, geranial (52.13 ), and neral (37.65 ) had been detected because the most important constituents. The evaluation of DPPH radical scavenging activity and ferric lowering antioxidant energy showed that BCEO exhibited robust antioxidant activity at IC50 of 42.57 /mL and EC50 of 20.03 /mL, respectively. The antibacterial activity final results showed that BCEO exhibited stronger antibacterial activity against Gram-positive bacteria (Staphylococcus aureus and Staphylococcus epidermidis) than against Gram-negative bacteria (Escherichia coli and Klebsiella pneumoniae).Anti-Mouse PD-L1 Antibody (10F.9G2) medchemexpress For the agar disk diffusion technique, S.Quinpirole In Vitro epidermidis was one of the most sensitive to BCEO with an inhibition zone diameter of 50.17 mm, followed by S. aureus (31.13 mm), E. coli (20.33 mm), and K. pneumoniae (12.67 mm). The results in the microdilution system showed that BCEO exhibited the highest activity against S.PMID:29844565 epidermidis and S. aureus, using the minimal inhibitory concentration (MIC) worth of six.25 /mL. BCEO acts as a potent antibiofilm agent with dual actions, inhibiting (85.ten to 96.44 ) and eradicating (70.92 to 90.73 ) of the biofilms formed by the four tested bacteria strains, compared with streptomycin (biofilm inhibition, 67.65 to 94.29 and biofilm eradication, 49.97 to 89.73 ). This study highlights that BCEO can potentially be a natural antioxidant agent, antibacterial agent, and antibiofilm agent that could possibly be applied inside the pharmaceutical and food industries. For the greatest from the authors’ information, that is the initial report, on the antibiofilm activity of BCEO against 4 popular nosocomial pathogens. Key phrases: Backhousia citriodora; essential oil; chemical composition; antioxidant; antibacterial; antibiofilmCopyright: 2022 by the authors. Licensee MDPI, Basel, Switzerland. This short article is an open access report distributed below the terms and conditions in the Creative Commons Attribution (CC BY) license ( creativecommons.org/licenses/by/ 4.0/).1. Introduction Antibiotics, that are also named antibacterial or antimicrobial drugs, have considerably improved human wellness and life expectancy by stopping or treating variousMolecules 2022, 27, 4895. doi.o.