Document Type : Research Paper
Authors
1 Research Division of Natural Resources, Isfahan Agricultural and Natural Resources Research and Education Center, Agricultural Research Education and Extension Organization (AREEO), Isfahan, Iran
2 Medicinal Plants and By-products Research Division, Research Institutes of Forest and Rangelands, Agricultural Research Education and Extension Organization (AREEO), Tehran, Iran
3 Horticulture Crops Research Department, Isfahan Agricultural and Natural Resources Research and Education Center, Agricultural Research Education and Extension Organization (AREEO), Isfahan, Iran
Abstract
Background and objectives: Ziziphora is a medicinal genus belonging to the Lamiaceae family. This genus comprises 18 species worldwide, of which three annual species, including Z. capitata, Z. persica, and Z. tenuior, along with one perennial species (Z. clinopodioides), grow in Iran. Except for Z. persica, the remaining species are distributed across the habitats of Isfahan province. The aerial parts of these plants emit a fragrant aroma during flowering, and today their bioactive compounds are widely used in pharmaceutical formulations to treat cough, heartache, intestinal inflammation, uterine infections, menstrual pain, nausea, and various cardiovascular disorders. Ziziphora essential oil contains valuable constituents, including pulegone and 1,8-cineole, with their proportions differing among species. The objective of this research was to evaluate the quantitative yield and essential oil composition of species within this genus in Isfahan province, and to assess their feasibility for introduction into the country’s agricultural production system.
Methodology: This study was conducted at the Fozveh Research Station of Isfahan between 2019 and 2020. The species examined included Z. clinopodioides, Z. tenuior, and Z. capitata. Seeds of the annual species were cultivated in February of both 2019 and 2020. The perennial species was sown in February 2019 inside a greenhouse using seedling trays filled with peat moss, and the resulting seedlings were transplanted to the field in April. Plants were established using a randomized complete block design with three replications. Quantitative traits such as plant height and leaf biomass were measured at the flowering stage (defined as more than 70% flowering). Plants within one square meter of each plot were harvested to determine dry biomass, while the remaining plants were retained to measure thousand-seed weight and seed yield. Essential oils were extracted by hydrodistillation using a Clevenger apparatus. Essential oil composition was quantified by gas chromatography (GC), and qualitative identification of compounds was performed using gas chromatography/mass spectrometry (GC/MS).
Results: The three Ziziphora species exhibited significant differences in plant height, dry aerial biomass, dry-to-fresh weight ratio of aerial parts, seed weight per plant, thousand-seed weight, leaf and seed yield, and essential oil percentage and yield. The highest plant height (38 cm), leaf yield (3800 kg/ha), and seed yield (95 kg/ha) were recorded in Z. clinopodioides during the second year. Essential oil content among the species ranged from 0.5% to 1.53%, with the highest percentage and yield, 1.53% and 57 kg/ha, respectively, observed in Z. clinopodioides in the second year. Essential oil profiling demonstrated interspecific and interannual differences in both the type and number of identified compounds. Z. clinopodioides presented 17 and 20 compounds in the first and second year, constituting 74.7% and 91.9% of the total essential oil. The 1,8-cineole, reaching 44.5% and 31.6%, was the dominant compound in the first and second years. Camphene (3.4%), sabinene (4.8%), α-terpinene (3.1%), and linalool (3.2%) were also key constituents. In Z. tenuior, 14 and 10 compounds were identified in the first and second years, accounting for 85.6% and 97.5% of the essential oil. The primary compound in both years was pulegone, measured at 64.3% in the first year and 89.5% in the second year. p-Mentha-3-en-8-ol and 1,8-cineole, at 7.6% and 4.9% were the most abundant constituents after pulegone, respectively, in the first year. In Z. capitata, 9 and 7 compounds were detected across the two years, representing 99.4% and 90.5% of the total essential oil. The major constituents in the first year were piperitone (25.3%), thymol (26.3%), and carvacrol (30.1%); however, in the second year, piperitone dominated at 42.2%.
Conclusion: Considering that Ziziphora currently lacks a defined position in the national agricultural system and given the superior quantitative and qualitative performance of Z. clinopodioides compared with the other species, as well as its considerable essential oil yield and valuable chemical constituents, it can be proposed as a promising new candidate for large-scale cultivation and integration into the country’s agricultural production framework.
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