Identifying the optimal month for target essential oil components in rosemary: A monthly chemical composition analysis
Journal of Essential Oil-Bearing Plants, vol.29, no.2, pp.528-536, 2026 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 29 Issue: 2
- Publication Date: 2026
- Doi Number: 10.1080/0972060x.2026.2660956
- Journal Name: Journal of Essential Oil-Bearing Plants
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, CAB Abstracts, Academic Search Ultimate (EBSCO)
- Page Numbers: pp.528-536
- Keywords: Chemical composition, Essential oil, GC–MS, Ontogenetic changes, Rosmarinus officinalis, Seasonal variation
- Hatay Mustafa Kemal University Affiliated: Yes
Abstract
Rosmarinus officinalis L. is an economically important medicinal and aromatic plant whose essential oil yield and composition are strongly influenced by ontogenetic and seasonal factors. This study aimed to determine the monthly variations in essential oil content and chemical composition of rosemary leaves throughout the year 2022 under the ecological conditions of Hatay, Türkiye. Fresh plant samples were collected monthly, and essential oils were obtained by hydrodistillation using a Clevenger apparatus. Chemical components were identified by GC–MS. Essential oil yield showed significant monthly fluctuations, with the highest content recorded in September (1.00%) and the lowest in November (0.33%). A total of 35 components were identified, representing 97.98–99.94% of the total oil. Major constituents included camphor (13.41–21.53%), verbenone (7.71–18.29%), borneol (7.35–14.65%), eucalyptol (8.09–12.20%), and α-pinene (5.72–12.02%). Principal component analysis effectively discriminated the months based on chemical profiles, indicating strong ontogenetic and seasonal differentiation. These findings provide valuable insights into determining the most suitable harvest periods for obtaining specific essential oil components and optimizing raw material quality for food, pharmaceutical, and cosmetic industries.