_____________________________________________________________________________________________________ *Corresponding author: Email: npassun7@gmail.com, papiasntezi@students.mu.ac.ke; Asian Journal of Applied Chemistry Research 9(2): 42-56, 2021; Article no.AJACR.72383 ISSN: 2582-0273 Variation of Yield and Chemical Composition of Essential Oil from Cupressus lusitanica Growing in Different Agro-ecological Zones of Rwanda Papias Nteziyaremye 1,2* , Jackson Cherutoi 1 , Jacqueline Makatiani 2,3 and Théoneste Muhizi 4 1 Department of Chemistry and Biochemistry, School of Sciences and Aerospace Studies, Moi University, P.O. Box 3900-30100, Eldoret, Kenya. 2 Africa Center of Excellence II in Phytochemicals, Textile and Renewable Energy (ACE II PTRE), Moi University, P.O. Box 3900-30100, Eldoret, Kenya. 3 Department of Biological Sciences, School of Sciences and Aerospace Studies, Moi University, P.O. Box 3900-30100, Eldoret, Kenya. 4 Department of Chemistry, College of Science and Technology, University of Rwanda, P.O.Box 3900, Kigali, Rwanda. Authors’ contributions This work was carried out in collaboration among all authors. Authors PN, JC, JM and TM designed the study. Author PN collected samples and performed laboratory analyses. Author TM provided analytical support and analyzed the collected data. Author PN performed literature search and wrote the first draft of the manuscript. All authors revised and approved the final manuscript. Article Information DOI: 10.9734/AJACR/2021/v9i230212 Editor(s): (1) Prof. Angélica Machi Lazarin, State University of Maringá, Brazil. Reviewers: (1) Manojkumar U. Chopade, Dr. Babasaheb Ambedkar Marathwada University, India. (2) Pham The Hue, Tay Nguyen University, Viet Nam. Complete Peer review History: https://www.sdiarticle4.com/review-history/72383 Received 14 June 2021 Accepted 18 August 2021 Published 25 August 2021 ABSTRACT Chemical composition and essential oil contents among essential oil-bearing plants are mostly influenced by different factors including ecological features of habitat. In this study, variation in yield and chemical composition of essential oils (EOs) from the leaves of Cupressus lusitanica Mill. (Cupressaceae) in different regions of Rwanda was investigated. Extraction of essential oils from fresh leaves of C. lusitanica collected in March 2021 and April, 2021 from three different ecological zones of Rwanda, Buberuka highland zone (Burera), Central plateau zone (Huye) and Eastern Original Research Article