Document Type : Research Paper
Authors
1 Ph.D. student, Department of Horticultural Science, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran
2 Department of Horticultural Science, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran
Abstract
Background and Objectives: Eryngium billardieri, known as “Zul” or “Boghnagh,” and Eryngium caucasicum, known as “Chuchagh,” are two important species among the 11 known species of the Eryngium genus in Iran. Plants of this genus are used to produce hydrosol, which is claimed to reduce blood glucose levels. Although the essential oil content of these species is relatively low, their diversity of volatile compounds is high. The aim of this study, consistent with previous research, is to investigate the water-soluble and water-insoluble volatile compounds of these two species. During hydrosol extraction from these plants, known as "Aragh-e Boghnagh," volatile compounds are transferred into the water; therefore, identifying water-soluble and water-insoluble volatile compounds is crucial for understanding the chemical composition of these species.
Material and Methods: In this study, E. billardieri (Zul or Boghnagh) was collected from three locations: Ganjname (GN, Hamedan province), Lardam (DL, Damavand, Tehran province), and Razghan (RZ), and E. caucasicum (Chuchagh) from Bojaq (BO) National Park (Gilan province) and Abr village (RA, Semnan province) at altitudes of 2800, 2450, 1750, -11, and 2056 m above sea level, respectively. Shade-dried plant materials were subjected to hydrodistillation using a Clevenger-type apparatus. Essential oil content was calculated on a weight/weight (%) basis. After essential oil extraction, 100 ml of hydrosol was collected for fractionation using 100 ml ethyl acetate, performed in three replicates. The percentage of the organic fraction was calculated as weight/volume (grams per 100 ml of hydrosol). Essential oil composition was analyzed using gas chromatography/mass spectrometry (GC/MS) and quantified by GC-FID.
Results: The essential oil yields for all samples were 0.15%, 0.11%, 0.37%, 0.10%, and 0.12% w/w for GN, DL, RZ, BO, and RA, respectively. The main components of E. billardieri essential oils were 2,3,6-trimethylbenzaldehyde (18.8%, 16.8%, 12.3%), sesquicineole (31.3%, 28.8%, 40.5%), and β-bisabolenal (9.2%, 13.8%, 7.3%) for GN, DL, and RZ, respectively. The main components of E. caucasicum essential oils were trans-caryophyllene (20.3% and 26.5%), β-bisabolene (7.4% and 9.8%), β-sesquiphellandrene (30.1% and 20.2%), and cis-falcarinol (16.6% and 23.2%) for RA and BO, respectively. The yields of ethyl acetate fractions were 0.031, 0.012, 0.023, 0.024, and 0.008 g per 100 ml of hydrosol for Of-GN, Of-DL, Of-RZ, Of-BO, and Of-RA, respectively. The main components of these fractions were 2,3,6-trimethylbenzaldehyde (45.5%, 30.2%, 22.9%), sesquicineole (12.0%, 8.1%, 14.6%), 3-methyl-2(5H)-furanone (9.1%, 12.4%, 17.8%), and p-vinyl-guaiacol (11.4%, 14.6%, 12.3%) for Of-GN, Of-DL, and Of-RZ, respectively. For Of-RA and Of-BO, the main components were 3-methyl-2(5H)-furanone (6.7% and 21.8%), trans-β-ocimene (7.8% and 16.8%), p-vinyl-guaiacol (15.2% and 11.6%), and caryophyllene oxide (23.7% and 14.8%), respectively.
Conclusion: By identifying water-soluble and water-insoluble volatile compounds, the relationships between these compounds were clarified. In the fractions of both species, p-vinyl-guaiacol and 3-methyl-2(5H)-furanone were the main compounds, which were not detected even in trace amounts in the essential oils. Additionally, 2,3,6-trimethylbenzaldehyde was observed in the essential oil and organic fractions of both species, with higher content in E. billardieri than in E. caucasicum. Moreover, 2,3,4-trimethylbenzaldehyde was in both the essential oil and organic fraction of E. caucasicum hydrosol but only in the essential oil of E. billardieri.
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