Document Type : Research Paper
Authors
1 1Department of Horticultural Science, Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran
2 3Department of Biotechnology, Persian Gulf Research Institute, Persian Gulf University, Bushehr, Iran
Abstract
Background and Aim: The Vitex pseudo-negundo plant, belonging to the Lamiaceae family, is valued in traditional medicine due to its medicinal properties. This plant is used to treat inflammation, pain, and hormonal disorders. Its essential oil contains active compounds such as alpha-pinene and limonene, which play a significant role in its therapeutic effects. To investigate the functional diversity and composition of the essential oil of this valuable plant, 50 populations from natural habitats across 12 provinces of the country were collected and studied.
Materials and Methods: In this study, 50 seed samples of Vitex pseudo-negundo were collected from diverse geographical regions across Iran. The collected seeds were thoroughly cleaned and then dried under shade at ambient temperature (approximately 25–30°C) for two weeks to preserve their volatile components. Essential oil extraction was performed by hydrodistillation using a Clevenger-type apparatus. For each extraction run, 170 grams of the dried seed powder were placed in a round-bottom flask and mixed with 500 mL of distilled water. During this period, the vapor containing essential oil was condensed and collected in the graduated tube of the apparatus. The extracted oil was then separated from water, dried over anhydrous sodium sulfate to remove any residual moisture, and stored in sealed dark vials at 4°C until further analysis. The oil yield was calculated based on the dry weight of the seeds. For chemical characterization, the essential oil samples were analyzed using gas chromatography-mass spectrometry (GC-MS) with an Agilent 7890A model equipped with a (HP-5-MS) capillary column. Helium was used as the carrier gas at a constant flow rate. The identification of individual compounds was carried out by comparing their mass spectra with those stored in the Wiley and Adams libraries, as well as by calculating and matching their retention indices relative to a series of n-alkane standards. This comprehensive approach enabled accurate determination of the major and minor volatile constituents present in each population.
Results: The results showed that the essential oil yield in the studied populations varied depending on the geographical region, ranging from 0.29% to 0.59%. The highest essential oil yield (0.59%) was observed in populations from Zarful, Dasht-e Mook, Tang-e Pirzal, and Simareh. In contrast, the lowest yield (0.29%) was found in 13 different regions, including Tang-e Abolhayat, Karend, Sardasht, Farashband, Masjed Soleyman, Zeydun, Zeydun Behbahan, Pol-e Keshkan, Shush, Sheykhan, Gachgaran, Bouger, and Sorkheh Dizeh. Analysis of the essential oil composition of V. pseudo-negundo seeds identified eight major compounds, with varying abundances among different populations. These compounds included alpha-pinene (11.24–28.64%), limonene (4.63–17.56%), terpinyl acetate (1.18–13.20%), alpha-eudesmol acetate (4.44–10.58%), trans-caryophyllene (2.12–12.6%), beta-eudesmol (1.14–8.24%), geranyl linalool (2.41–6.56%), and verbenene (1.52–4.7%). Overall, alpha-pinene and limonene were found to be the primary compounds in all populations. Additionally, alpha-eudesmol acetate was consistently present in most regions at stable levels (5–10%). The highest concentration of this compound was observed in Pol-e Dokhtar (10.58%) and Lashkar Bolouki (10.24%), while the lowest was in Karend towards Sar Pol-e Zahab (4.44%). Trans-caryophyllene was also detected in most samples, with the highest (12.6%) and lowest (2.12%) amounts reported in Ghaemiyeh and Kashkoo village, respectively. The results of cluster analysis and biplot analysis of Vitex pseudo-negundo based on the quantity and quality of essential oil divided the habitats of this plant into five main groups.
Conclusion: Results indicated that essential oil yield and compositional diversity are influenced by various factors, including genetic origin, climatic conditions, and environmental characteristics. Given the high percentage of alpha-pinene in the essential oil of this plant, its use in pharmaceutical, food, and cosmetic industries could be of significant interest.
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