ارزیابی ترکیبات فیتوشیمیایی اسانس زیره سبز (Cuminum cyminum L.) کشت شده در برخی مناطق استان سیستان و بلوچستان

Introduction

Iran is a region that is incredibly rich in terms of both the number and variety of medicinal plants. The province of Sistan and Baluchestan is not only one of the richest provinces in terms of medicinal plants in the country, but it is also a major center for the distribution of cumin in Iran. Green cumin (Cuminum cyminum L.) is an annual, herbaceous, and aromatic plant, native to the East Asian region. The seeds of cumin are the most important part of this plant and are considered the main source of its active compounds. Considering the medicinal and economic importance of cumin, this research was conducted to investigate, compare, and identify the various phytochemical compounds present in the essential oil of cultivated cumin in different regions of Sistan and Baluchestan province. This study aims to determine areas with potential for high essential oil yield and phytochemical compounds to develop the cultivation of cumin in the province and utilize the results of this study in future research.



Materials and methods

This research was conducted to evaluate the quantitative and qualitative aspects of the essential oil of cumin cultivated in various regions of Sistan and Baluchestan province. For this purpose, seeds grown in four selected farms within the geographical areas of the targeted counties, including Mirjaveh, Zabol, Taftan, and Khash, were harvested. The essential oil was extracted using water distillation, and after measuring the amount of essential oil, the separation and identification of compounds were performed using gas chromatography and gas chromatography coupled with mass spectrometry. The experiment was conducted in a completely random design with three replications. The main components found in cumin seeds obtained from four different regions of Sistan and Baluchestan province include cumin essential oil and 15 distinct phytochemical compounds. These compounds consist of gamma-terpinen-7-al, α-terpinene-7-al, cumin aldehyde, 4-trans-caranone, gamma-terpinen, 1,8-cineole, limonene, p-cymene, α-terpinene, α-phellandrene, myrcene, beta-pinene, sabinene, α-pinene and α-thujene.



Results and discussion

Based on the results of green cumin harvested from different regions of Sistan and Baluchestan province, a significant difference in the percentage of essential oil was observed. The difference ranged from 2.44% to 3.56%. The highest and lowest percentages of essential oil were in the Taftan and Zabol regions, respectively. In addition to the essential oil, 15 phytochemical compounds with different percentages were identified in the cultivation of the following regions. The highest and lowest amounts of myrcene were related to the green cumin of the Khash and Taftan, respectively.Green cumin cultivated in the Khash region exhibited the highest concentration of α-phellandrene. According to the results, the green cumin from the Khash region has the highest amount of aromatic essential oil due to having the highest amount of myrcene and α-phellandrene. The results related to α-phellandrene phytochemical composition showed that the Khash region had the highest amount (0.915%) and Taftan had the lowest amount (0.348%). According to the results, the highest and lowest amounts of phytochemical composition of p-cymene were related to Zabol (8.43%) and Khash (5.48%) regions, respectively. The results of the comparison of mean cumin aldehyde showed that the regions of Mirjaveh (14.52%), Zabol (14.56%), and Taftan (12.96%) had the highest amounts of cumin aldehyde. The results showed that the phytochemical compounds gamma-terpinene (26.34%), gamma-terpinene-7-al (25.46%) and β-pinene (18.59%) are the most (in total more than 70% of phytochemical compounds present in cumin) and phytochemical compounds α-terpinene (0.19%), 1,8-cineole (0.28%), limonene (0.36%) and α-thujene (0.39%) ) the least (in total one percent of the phytochemical compounds in cumin) constitute the total amount of identified phytochemical compounds. The correlation relationships between the phytochemical compounds in green cumin in this study showed that these relationships can be used as indicators to estimate the amounts of other phytochemical compounds. The biplot results demonstrated a wide diversity among Sistan and Baluchestan province regions regarding the phytochemical composition of their green cumin.



Conclusions

In this study, the persentage of essential oil from green cumin cultivated in different regions varied between 2.44% and 3.56%. Analysis of the results showed that there were significant differences among the studied regions in terms of five phytochemical compounds. Accordingly, the highest percentage of essential oil was found in cultivated green cumin p in the Taftan region, the highest percentage of myrcene and alpha-felandrene in cultivated green cumin in the Khash region, and the highest percentage of cuminaldehyde and p-cymene in cultivated green cumin in the Zabol region. The results of this research indicate the impact of higher altitudes (Taftan and Khash) on the cultivation of essential oil and some essential oil components. Thus, with the increase in altitude above sea level and consequently increased rainfall and decreased temperature, the percentage of essential oil and essential oil compounds such as myrcene and α-phellandrene increased, while with decreasing altitude and consequently reduced rainfall and increased temperature in the Zabol region, the phytochemical compounds cuminaldehyde and p-cymene increased. Therefore, these areas can be used for the cultivation of cumin rich in these compounds. Additionally, these regions can be introduced as suitable locations for further research in the field of producing these phytochemical compounds.