ANTIBACTERIAL EFFICACY OF FIVE NATURAL ESSENTIAL OILS USED IN YEMEN: A COMPARATIVE STUDY

Background and objective: Due to the increasing resistance to synthetic antibiotics and preservatives, there is growing interest in exploring natural alternatives. This study aimed to evaluate the antibacterial potential of five commercially available essential oils in the Yemeni market Azadirachta indica (Neem), Moringa oleifera, Rosmarinus officinalis (Rosemary), Salvia officinalis, and Origanum majorana against selected Gram-positive and Gram-negative bacterial strains. Method: Agar diffusion was used to investigate the antibacterial activity of essential oils from five plants: Azadirachta indica (neem), Moringa oleifera, Rosmarinus officinalis (rosemary), Salvia officinalis, and Origanum majorana. Result:  Significant differences in the inhibitory effects of the plant oils of neem, Moringa oleifera, Rosmarinus officinalis, Salvia officinalis, and Origanum majorana against Gram-positive and Gram-negative bacteria were found during the antimicrobial screening process. Nearing the effectiveness of gentamicin (25 mm), Salvia officinalis and neem oils demonstrated the highest action against Gram-positive Staphylococcus aureus (22 mm and 20 mm inhibition zones, respectively). Rosmarinus officinalis, on the other hand, demonstrated a low level of efficacy (10 mm). Most oils were less effective against Gram-negative organisms, and E. coli showed resistance to all save Rosmarinus officinalis (12 mm). Conclusions: These results demonstrate the potential of oils produced from plants, especially Origanum majorana, neem, and Salvia officinalis, as antibacterial agents against Gram-negative bacteria highlights the need for more research into maximizing their use, either alone or in combination with other antibiotics, despite their encouraging efficacy against Gram-positive bacteria.                     Peer Review History: Received 9 April 2025;   Reviewed 14 May 2025; Accepted 20 June; Available online 15 July 2025 Academic Editor: Dr. Ahmad Najib, Universitas Muslim Indonesia,  Indonesia, ahmad.najib@umi.ac.id Reviewers: Antonio José de Jesus Evangelista, Federal University of Ceará, UFC, Brazil, tony_biomed@hotmail.com Prof. Abdulwahab Ismail Al-kholani, Dean of Faculty of Dentistry at 21 September University, Yemen. prof_khholani@yahoo.com