Essential Oil Content and Composition of Nepeta kotschyi Boiss. (Lamiaceae) from Iran during Different Phenological Stages

Essential oils (EOs) because of being natural compounds and having antibacterial properties are important for health. The chemical composition of EOs might be affected by environmental conditions and plant growth and development stages. In this study, the essential oils and chemical compositions of aerial parts of Nepeta kotschyi Boiss. (Lamiaceae) were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS) at different plant phenological (in mid vegetative, 50% of flowering and fruiting) stages. The results showed that the EOs of Nepeta was affected by plant growth and development stages. So, both of content and their constituents were different in the plant phenological stages. The average percentage of EOs was ranged from 2.48 (in vegetative), 0.8 (in 50% of flowering), and 0.82 (in fruiting) stages. According to the results, 21 compounds with the range of 0.84-13.04 % in vegetative, 3 compounds with the range of 10.93-53.25% in 50% of flowering and 6 compounds with the range of 8.51-45.22% in fruiting stages were identified. The compounds 1,6,10-Nerolidol in vegetative (13.04%), Spathulenol in 50% of flowering (53.25%) and Caryophyllene oxide in fruiting stages (45.22%) had the highest value. Based on the results, the highest percentage of essential oils and compounds were related to the vegetative stage. The present study is the first report of the essential oil content of Nepeta during different plant phenological stages. The results of this study can be useful to understand the proper harvest time in Nepeta.