Document Type : Research Paper
Authors
1 .Department of Horticultural Science, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran
2 Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
3 Department of Horticultural Science, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran
Abstract
Background and Objectives: Nepeta crispa Willd., commonly known as Mofarrah, is an endemic plant of Iran belonging to the Lamiaceae family. Its distribution in Iran is limited to the western region, specifically Hamadan province. In this study, the plant was collected from three habitats in Hamadan province, Arzanfood (Hamedan city), Gashani (Tuyserkan city), and Piste Eski (Hamedan city) at elevations of 3021, 2783, and 2686 meters above sea level, respectively, during the flowering stage. The research aimed to investigate the essential oil content and water-soluble volatile compounds (hydrosol) of N. crispa and to compare these compounds across different habitats. The study also sought to identify variations in essential oil main components and hydrosol to evaluate the influence of ecological characteristics on the plant's chemical composition.
Methodology: The plant samples were shade-dried, and essential oil was extracted using a Clevenger apparatus for 3 hours. Water-soluble volatile compounds (hydrosol) were collected by leaving the exit part of the Clevenger open to condense vapor into liquid. The hydrosol was then separated using ethyl acetate solvent in a separatory funnel. The essential oil and hydrosol were analyzed using GC-FID and GC/MS.
Results: The essential oil yields from the Arzanfood, Gashani, and Piste Eski samples were 2.01%, 1.97%, and 1.82% (w/w), respectively. The concentration of water-soluble volatile compounds in the hydrosol were 0.15, 0.11, and 0.12 grams per 100 ml, respectively. The primary compounds identified in the essential oil were 1,8-cineole (49.4%, 48.5%, and 60%), 4aα,7β,7aα-nepetalactone (27%, 3.7%, and 8.3%), 4aα,7α,7aα-nepetalactone (0.1%, 23.5%, and 7.2%), and β-pinene (4.3%, 5.4%, and 6.1%) for Arzanfood, Gashani, and Piste Eski, respectively. In the hydrosol, the main components were 4aα,7β,7aα-nepetalactone (74.1%, 40.3%, and 57.1%) and α-pinene oxide (4.6%, 7.1%, and 5.2%).
Conclusion: The variation in essential oil yield across different habitats highlights the impact of ecological factors on the quantity of essential oil. The highest essential oil yield (2.01%) was observed in the Arzanfood sample, which also has the highest elevation among the studied regions. A total of 22 compounds were identified in the essential oil, with 18, 20, and 17 compounds detected in the Arzanfood, Gashani, and Piste Eski samples, respectively. The dominant compound in the essential oil was 1,8-cineole, while 4aα,7β,7aα-nepetalactone was the most abundant compound in the hydrosol. This study marks the first report on the hydrosol analysis of N. crispa from different habitats.
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