Tehran University of Medical Sciences Acta Biochimica Iranica 0001-5261 3 1 2025 03 20 23 29 Behnam Mahdavi Department of Chemistry, Faculty of Science, Hakim Sabzevari University, Sabzevar, Iran Wan A. Yaacob School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, 43600, Malaysia 2025 07 27 Objective: The antimicrobial and antioxidant activities of essential oils are important because they offer a natural and effective agent. This study aims to investigate the chemical composition, antioxidant, and antimicrobial activity of the essential oil of leaves of Etlingera velutina. Methods: The essential oils from the leaves of Etlingera velutina were obtained using a Clevenger-type apparatus and the chemical compositions of the oils were identified by GC-FID and GC-MS methods. The antioxidant activity of the oil was analyzed using three common assays. The antimicrobial activity of the oil was evaluated by disc diffusion assay. Results: The oil consists of sesquiterpene hydrocarbons with the highest percentage (63.12 %). Aromadendrene (58.30%), α-pinene (10.82%), and caryophyllenyl alcohol (10.21%) were identified as the main components of the essential oil. The leaf oil exhibited antioxidant activity in all the tests: DPPH radical scavenging activity (RSA); β-carotene bleaching (BCB); and ferrous ion chelating ability (FIC). The oil presented the activity against B. subtilis, E. aerogenes, P. vulgaris, and Candida. Parapsilosis. E. aerogenes. Conclusion: The data suggest that the essential oil of the leaves of Etlingera velutina revealed moderate activity against selected microorganisms in antimicrobial and antioxidant assay.  It may be considered as a natural agent for bioactivty. https://abi.tums.ac.ir/index.php/abi/article/view/145 https://abi.tums.ac.ir/index.php/abi/article/download/145/98