Phytochemistry (extraction, identification and measurement of active components)
Hosein Ahmadi; Mohammad Reza Fatahi; Zabihollah Zamani; Majid Shokrpour; Mohammad Reza Morshedloo
Abstract
Background and Objective: Thymus daenensis Celak. is an endemic medicinal plant of Iran valued for its high thymol content and essential oil content. A novel approach to enhancing plant tolerance to environmental stress is applying nanoparticles as bioelicitors. Nanosilicon and ...
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Background and Objective: Thymus daenensis Celak. is an endemic medicinal plant of Iran valued for its high thymol content and essential oil content. A novel approach to enhancing plant tolerance to environmental stress is applying nanoparticles as bioelicitors. Nanosilicon and nanoselenium are among the nanoparticles that can enhance stress tolerance and improve plant performance by influencing physiological and biochemical pathways. This study assessed the combined effects of nanosilicon and nanoselenium treatments on the agronomic, phytochemical, and physiological traits of T. daenensis under drought stress. Methodology: The study was conducted in a research field using a split-plot experimental design. The experimental factors consisted of two water-stress levels (control and irrigation cessation before flowering) and five concentrations of the combined nanosilicon and nanoselenium treatment (0, 10, 20, 40, and 60 mg/L). We measured agronomic traits, including dry matter yield, essential oil yield, and thymol yield. We also determined mineral element concentrations (nitrogen, phosphorus, potassium, calcium, magnesium, and iron) and physiological indices (chlorophyll, malondialdehyde, and hydrogen peroxide). Multivariate regression analysis and artificial neural network (ANN) modeling were used to analyze the observed trends and model the data.Results: The results showed that drought stress significantly reduced dry matter yield, essential oil yield, and thymol yield, with more pronounced reductions during the second harvest. Nano-elicitor application positively affected certain agronomic traits, particularly at a concentration of 10 mg/L, which increased dry matter yield by 18%. However, concentrations above 20 mg/L produced adverse effects and reduced plant performance. Regarding mineral element concentrations, nano-elicitor application increased the uptake of nitrogen, phosphorus, calcium, magnesium, and iron, whereas potassium levels remained largely unchanged under stress conditions. Physiological assessments showed that drought stress increased malondialdehyde and hydrogen peroxide levels, indicating enhanced oxidative stress. However, applying the nano-elicitors at 10 mg/L effectively reduced hydrogen peroxide levels under drought stress. ANN modeling demonstrated greater predictive accuracy than conventional regression models and proved to be a reliable approach for predicting plant performance under different stress and treatment conditions. The ANN model exhibited a lower standard deviation and a higher coefficient of determination (R²), exceeding 95% when predicting essential oil and thymol yield. The modeling results further demonstrated that artificial neural networks, as an artificial intelligence approach, provided more accurate predictions than six other commonly used regression models.Conclusion: Overall, the findings indicated that nanosilicon and nanoselenium can positively affect certain agronomic and physiological traits of T. daenensis, although these effects depend on the application concentration and the prevailing stress conditions. Under drought stress, the 10 mg/L treatment produced the most favorable overall outcomes, as it improved yield and helped reduce oxidative stress. ANN modeling also demonstrated strong predictive performance and offered a useful and optimized approach for managing medicinal plant cultivation under stressful environmental conditions. Further research should examine the molecular mechanisms through which nano-elicitors influence plant regulatory and metabolic pathways. The findings suggest that applying nanosilicon and nanoselenium at appropriate concentrations may serve as a practical strategy to improve the performance of medicinal plants exposed to drought stress. However, additional studies are needed to clarify the physiological and molecular mechanisms through which these nanoparticles act in plants and to evaluate their long-term impacts on soil properties and the environment.
Biotechnology
Arman Haghnazri; Mohammadreza Azimi; Ali Amarlou
Abstract
Background and Objective: Ferula gummosa Boiss. is a perennial plant belonging to the family Apiaceae and is native to Iran. Besides its medicinal properties, this valuable plant is used in the cosmetics and personal care industries, as well as in jewelry making. One major difficulty ...
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Background and Objective: Ferula gummosa Boiss. is a perennial plant belonging to the family Apiaceae and is native to Iran. Besides its medicinal properties, this valuable plant is used in the cosmetics and personal care industries, as well as in jewelry making. One major difficulty in cultivating F. gummosa is its prolonged dormancy phase, which can last up to nine months under natural conditions. This extended dormancy, combined with excessive harvesting from natural habitats, has placed the species at risk of extinction in the wild. Therefore, this study aimed to overcome seed dormancy through embryo culture techniques and identify the F. gummosa ecotype with the most promising response to tissue culture. In addition, this study investigated the effects of different concentrations of plant growth regulators on callus induction and subsequent regeneration, with the ultimate objective of optimizing micropropagation techniques and supporting the large-scale propagation of F. gummosa.Methodology: Four F. gummosa ecotypes were initially collected from three counties: Kashan, Abadeh, and Khalkhal. To determine embryo germination percentage and rate, embryos were aseptically excised from the seeds and cultured on Murashige and Skoog (MS) medium. The cultures were maintained in a growth chamber for one month to facilitate germination and seedling development. To evaluate callus induction across ecotypes, root explants were excised from seedlings developed through embryo culture. These explants were subsequently cultured on MS medium supplemented with indole-3-acetic acid (IAA) at 1 and 1.5 mg/L and naphthaleneacetic acid (NAA) at 3 and 5 mg/L. The cultures were maintained in an incubator at 20°C until callus formation occurred. The resulting calluses were then evaluated for size and weight to assess growth performance. During the subsequent regeneration phase, selected calluses were transferred to MS medium containing kinetin (KIN) at concentrations of 2, 4, and 8 mg/L. Regenerative responses and growth performance were compared after two months of culture.Results: The embryo culture results showed that the Kashan ecotypes achieved the most favorable outcomes in terms of both germination percentage and germination rate. Furthermore, embryo culture effectively overcame the prolonged dormancy of F. gummosa, enabling viable seedlings to be obtained within one month. During the callus induction stage, the most vigorous calluses were obtained from Kashan ecotype cultured on medium supplemented with NAA at 5 mg/L. During the regeneration stage, organogenesis occurred in 42% of the calluses, with the medium supplemented with KIN at 4 mg/L yielding the most favorable results. In addition, 53% of the calluses continued to proliferate and developed into larger cell masses. The Kashan ecotype also demonstrated the most favorable performance during this stage, maintaining its superiority in the tissue culture response.Conclusion: The findings indicate that tissue culture techniques are suitable for propagating F. gummosa and can effectively overcome its prolonged dormancy period, which may extend to nine months under natural conditions. The favorable responses observed during both callus induction and regeneration further demonstrate that tissue culture techniques have considerable potential for large-scale propagation of this valuable medicinal plant and for shortening its growth cycle. Among the evaluated ecotypes, those derived from the Kashan population consistently showed better results in embryo culture, callus formation, and regeneration. These findings suggest that the Kashan ecotype is a promising candidate for further optimization of tissue culture protocols and the development of efficient micropropagation methods for the mass production and conservation of F. gummosa.
Improvement and breeding
Najmeh Hadi; Faezeh Daryaei; Mahdi Yahyazadeh; Samaneh Asadi Sanam
Abstract
Background and Objectives: Phenological studies are essential for developing agronomic management practices, production strategies, and plant breeding programs. Nepeta L. is one of the largest genera in the family Lamiaceae, and Iran is one of its major centers of origin and ...
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Background and Objectives: Phenological studies are essential for developing agronomic management practices, production strategies, and plant breeding programs. Nepeta L. is one of the largest genera in the family Lamiaceae, and Iran is one of its major centers of origin and diversity. Given the importance of this genus and the reported biological activities of its specialized metabolites, investigating national germplasm collections is important for their future use in breeding and crop management programs. The present study investigates phenological diversity and the timing and rate of reproductive structure formation under ex situ conditions in 21 populations of N. kotschyi Boiss. This species was selected for potential breeding and cultivation based on previous research by the first author, which evaluated flowering shoot production in terms of rate and frequency, as well as the quantity and quality of its phytochemical compounds, including essential oil and phenolic compounds. The present study contributes to the broader research needed to support the future breeding and cultivation of this species.
Methodology: Twenty-one populations of Nepeta kotschyi, representing two varieties, var. kotschyi and var. persica, were cultivated in a field in western Tehran to minimize environmental effects on the evaluations. Phenological observations were conducted during the second year of cultivation, following the onset of growth in early March. The phenological stages assessed included vegetative growth, budding, three successive stages of bud development, and flowering.
To quantify the rate of formation and development of reproductive structures, measurements were taken at two time points: Phase 1, 40 days after the onset of growth, and Phase 2, at the stage when more than 75% of the plants were flowering. The timing of Phase 2 was determined by recording the number of days elapsed since the onset of growth. At both phases, the average plant area and height were measured, and plant volume was estimated by multiplying these two measurements. The proportions of total plant volume occupied by vegetative and reproductive structures were then calculated for each phase. The rate of reproductive structure formation and development was calculated as the change in the proportion of reproductive structures between Phase 1 and Phase 2, divided by the number of days elapsed between the two phases. The resulting rate was expressed as a percentage per day (% day⁻¹). Cluster analysis was performed to identify the contributions of individual phenological traits to variation among populations, while principal component analysis (PCA) was used to characterize and group the populations based on their phenological traits.
Results: The results revealed significant differences among populations in the timing of growth and developmental stages, allowing them to be classified into three flowering groups: early-, intermediate-, and late-flowering populations. Although all populations were cultivated under the same environmental conditions, their distinct growth patterns suggest a substantial genetic contribution to the regulation of phenological development. The Kohgiluyeh and Boyer-Ahmad (Kb and K), Ardakan 2, and Ardakan 3 populations were identified as the most promising populations in terms of reproductive development, exhibiting the highest flowering percentages within the shortest periods. The occurrence of plants with markedly different flower colors and developmental stages within the same population, as observed in the Bafgh and Ardakan 3 populations, suggests the presence of considerable within-population diversity that could provide valuable genetic resources for future breeding programs. Cluster analysis classified the populations into four groups based on their phenotypic and phenological characteristics. Bootstrap analysis (100 replicates) supported the separation of the Isfahan and Kohgiluyeh and Boyer-Ahmad populations from those originating from Yazd, Khorasan, and Chaharmahal and Bakhtiari. Populations in Groups 1 and 2 were characterized by early flowering, whereas Group 3 consisted of late-flowering populations. Group 4, which contained the largest number of populations, encompassed all three flowering patterns, with intermediate-flowering populations being the most prevalent. The results of principal component analysis (PCA) were consistent with those of cluster analysis. The first two principal components explained 82.49% of the total variation among the studied populations.
Conclusion: This study revealed structured variation in the growth patterns of N. kotschyi populations and provided a valuable basis for the systematic use of this diversity in agricultural, medicinal, and conservation programs. These findings can support the selection of superior genotypes for developing improved cultivars, the sustainable management and conservation of genetic resources, and the enhancement of cultivation productivity for this valuable medicinal plant.
Identification, introduction, ecology and ethnobotany
Maryam Alipour; Maryam Haghighi; Mehdi Rahimmalek
Abstract
Background and objectives: Thyme (Thymus spp.) is an important medicinal and aromatic plant belonging to the Lamiaceae family. It is highly valued for its phenolic compounds and essential oils, which are widely used in the pharmaceutical, food, and cosmetic industries. The genus ...
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Background and objectives: Thyme (Thymus spp.) is an important medicinal and aromatic plant belonging to the Lamiaceae family. It is highly valued for its phenolic compounds and essential oils, which are widely used in the pharmaceutical, food, and cosmetic industries. The genus comprises more than 200 species and exhibits considerable genetic diversity in Iran, providing substantial potential for breeding programs. Drought is a major constraint on thyme production in semi-arid regions and can influence plant growth and essential oil composition. Quantitative indices for assessing drought tolerance, including the stress tolerance index (STI), geometric mean productivity (GMP), mean productivity (MP), harmonic mean (HM), and yield stability index (YSI), can be used to identify drought-tolerant genotypes. Previous studies on different Thymus species demonstrated that GMP and STI exhibit stronger correlations with biomass and essential oil yield than some other indices. Therefore, evaluating different populations under both drought-stress and non-stress conditions is essential for identifying superior genotypes with desirable agronomic and phytochemical characteristics.
Methodology: This study evaluated ten thyme (Thymus spp.) populations, comprising nine native Iranian populations and Th. vulgaris from Europe as a reference population. The experiment was conducted in pots under greenhouse conditions with natural light and a relative humidity of 65%. A two-factor factorial experiment was arranged in a completely randomized design (CRD) with three replications, each containing five pots per treatment. The potting substrate consisted of a mixture of field soil, sand, and well-rotted manure in a 1:2:3 ratio, with a total substrate weight of 5 kg per pot. Irrigation was managed according to soil field capacity and adjusted daily by weighing the pots. Two irrigation treatments were applied: 100% of field capacity as the control and 40% of field capacity as the drought-stress treatment. Aboveground dry biomass was harvested 50 days after the application of drought stress and subsequently dried. Essential oils were extracted from 100 g of dried plant material using hydrodistillation, and essential oil content was determined as a volumetric percentage. Quantitative drought tolerance indices, including STI, GMP, MP, HM, and the stress susceptibility index (SSI), were calculated. Analysis of variance and mean comparisons using the least significant difference (LSD) test were performed in SAS software. Correlation coefficients, cluster analysis using Ward’s method, and biplot diagrams were also employed to assess relationships among the measured traits and classify the populations according to their responses to drought stress.
Results: The results indicated that population, irrigation regime, and their interaction significantly affected aboveground dry biomass, essential oil content, and essential oil yield at the 5% significance level. Drought stress significantly reduced dry biomass in all populations, although the magnitude of the reduction varied among them. Th. pubescens, Th. kotschyanus-2, and Th. vulgaris exhibited the smallest reductions in biomass under drought stress. In contrast, essential oil content increased in most populations under drought conditions, with the highest values recorded in Th. fedtschenkoi and Th. kotschyanus-2. This increase may be attributable to the concentration of secondary metabolites associated with reduced vegetative growth. Analysis of quantitative drought tolerance indices revealed significant differences in drought stress among populations. Based on STI, GMP, HM, the yield index (YI), and the drought resistance index (DI), Th. kotschyanus-2 and Th. fedtschenkoi were identified as the most drought-tolerant populations, whereas Th. daenensis-1 and Th. daenensis-2 were the most sensitive. Principal component analysis showed that the first two principal components explained 57.98% of the total variation among the populations. The first component was primarily associated with drought tolerance indices, whereas the second was associated with sensitivity indices. The biplot and cluster analysis jointly classified Th. kotschyanus-2, Th. pubescens, and Th. vulgaris as high-performing, drought-tolerant populations. In contrast, Th. daenensis-1, Th. daenensis-2, Th. serpyllum, and Th. migricus were classified as drought-sensitive populations with relatively low performance.
Conclusion: Overall, the findings indicated that thyme populations responded differently to drought stress, with some populations maintaining relatively high performance or increasing essential oil content despite reduced vegetative growth. The STI, GMP, and HM indices were identified as the most reliable criteria for selecting drought-tolerant populations. Based on these indices, Th. kotschyanus-2 and Th. fedtschenkoi were identified as promising candidates for cultivation under drought conditions. These populations may therefore be valuable genetic resources for breeding programs aimed at improving drought tolerance and supporting the sustainable cultivation of thyme in arid and semi-arid regions
Biological effects of essential oils and extracts
Mohammad Khajeh Bami; Fatemeh Ebrahimi; Ghasem Mohammadi-Nejad
Abstract
Background and objective: Safflower (Carthamus tinctorius L.) is a strategic crop that has received considerable attention in recent years because of its medicinal and nutritional value. Given limited protein and water resources, safflower varieties are improved to enhance drought ...
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Background and objective: Safflower (Carthamus tinctorius L.) is a strategic crop that has received considerable attention in recent years because of its medicinal and nutritional value. Given limited protein and water resources, safflower varieties are improved to enhance drought resistance and increase seed and oil yields. Incorporating these cultivars into broiler diets may improve production performance, reduce foreign exchange expenditures associated with feed imports, and contribute to food security. Therefore, this study aimed to evaluate the effects of different inclusion levels of modified safflower seeds and meal (Fakhereh variety), compared with the corresponding inclusion levels of the commercial variety (Goldasht), as partial replacements for soybean meal on the growth performance, carcass characteristics, and meat quality parameters of broiler chickens.
Methodology: In total, 420 mixed-sex Ross 308 broiler chickens were randomly assigned to seven experimental treatments, with five replicates of 12 birds per treatment, from 15 to 42 days of age. The experimental treatments were as follows: (1) a corn- and soybean meal-based diet (control); (2) a basal diet containing 10% modified safflower seeds; (3) a basal diet containing 20% modified safflower seeds; (4) a basal diet containing 10% modified safflower meal; (5) a basal diet containing 20% modified safflower meal; (6) a basal diet containing 10% commercial safflower seeds; and (7) a basal diet containing 20% commercial safflower seeds. Environmental conditions, including lighting and temperature, were controlled in accordance with the recommendations provided by the Ross 308 producer. Growth performance parameters, including feed intake, body weight gain, and feed conversion ratio, were recorded weekly. The vaccination program was implemented in accordance with the recommendations of the local veterinarian. At 42 days of age, one broiler chicken per replicate was selected for slaughter to assess carcass characteristics and meat quality, resulting in five birds per treatment (n = 5). Carcass characteristics, including the relative weights of the eviscerated carcass, breast, thigh, and wings, were evaluated. Meat quality parameters, including water-holding capacity, pH, cooking loss, and drip loss, were also measured at 42 days of age. The data were analyzed using a completely randomized design and a general linear model (GLM) in Minitab (2016). Tukey’s test was used for pairwise comparisons at a significance level of 5%.
Results: Growth performance parameters, including average body weight gain, daily feed intake, and feed conversion ratio, were not significantly affected by the experimental treatments during any of the experimental weeks or throughout the entire experimental period (P > 0.05). However, during the 22–28-day period, body weight gain and feed conversion ratio showed trends toward improvement in the groups receiving diets containing 10% modified safflower meal (Fakhereh variety) and 20% commercial safflower seeds (Goldasht variety), compared with the control group. Assessment of meat quality revealed that the pH of the thigh muscle in broilers fed a diet containing 10% modified safflower seeds of the Fakhereh variety was significantly higher than that in the control group (P < 0.05). The other meat quality parameters, including water-holding capacity, cooking loss, and drip loss, were not significantly affected by the experimental treatments (P > 0.05). Furthermore, carcass characteristics, including the relative weights of the eviscerated carcass, breast, thigh, and wings, did not differ significantly among the experimental treatments (P > 0.05).
Conclusion: Overall, the findings indicated that including seeds or meal from different safflower cultivars at varying dietary levels did not significantly affect the growth performance, carcass characteristics, or meat quality parameters of broiler chickens. Therefore, including Fakhereh safflower seeds or meal at levels up to 20% in broiler diets does not appear to adversely affect growth performance, carcass characteristics, or meat quality under the conditions of the present study.
Improvement and breeding
Razieh Azimi; Bohloul Abbaszadeh; Masoumeh Layeghhaghighi; Aliashraf Jafari; Mahdi Yahyazadeh
Abstract
Background and Objectives: Given the economic value of many medicinal plant species in Iran and the demand from related industries, identifying and introducing superior accessions to medicinal plant producers can improve the quantity and quality of plant products, enhance their ...
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Background and Objectives: Given the economic value of many medicinal plant species in Iran and the demand from related industries, identifying and introducing superior accessions to medicinal plant producers can improve the quantity and quality of plant products, enhance their economic value, and contribute to the development of the medicinal plant industry. This study was carried out as part of complementary research designed to introduce selected medicinal plant cultivars for seed production and increase their cultivated area. The objective was to identify the superior Hypericum perforatum accession based on agronomic and phytochemical traits. Four accessions were selected from the preliminary research phase: A01 (Gene Bank accession code 10601) from Ardabil, A02 (Gene Bank accession code 33255) from Qazvin, A03 (Gene Bank accession code 33258) from Qazvin, and A04 (Gene Bank accession code 23335) from Khalkhal.
Methodology: Seeds of the superior H. perforatum accessions selected during the preliminary research phase were transferred to the Alborz Research Station in the winter of 2021. In spring 2022, the seeds were sown in the field using a randomized complete block design with five replications. In 2023, data were recorded during the flowering and seed-ripening stages. Morphological traits, flowering branch yield, and seed yield per hectare were measured. The above-ground parts of the plants were harvested at full flowering to assess their phytochemical characteristics. Different plant organs, including flowers, leaves, stems, and branches, were extracted separately using 80% methanol adjusted to pH 3 under ultrasonic treatment at 50 °C. Hypericin concentrations in the extracts were subsequently determined using high-performance liquid chromatography (HPLC). In addition, total phenolic, flavonoid, and anthocyanin contents, as well as antioxidant activity, were evaluated in the hydroalcoholic extract (80% ethanol) of the flowering branches.
Results: Statistical analysis revealed significant differences among the H. perforatum accessions in all morphological traits, individual plant weight, flowering branch yield, seed yield, and phenolic, anthocyanin, and hypericin contents at the 1% significance level. Flavonoid content and antioxidant activity differed significantly at the 5% significance level. Mean comparisons using the least significant difference (LSD) test showed that accession A02 from Qazvin had the greatest plant height (65.8 cm), crown circumference (222 cm), individual flowering plant weight (134.8 g), flowering branch yield (5,392 kg ha⁻¹), individual plant seed weight (12.3 g), and seed yield (492 kg ha⁻¹). The highest total phenolic content (6,240.8 μg gallic acid equivalents (GAE) g⁻¹ dry matter) was recorded in accession A04 from Khalkhal. In contrast, accession A03 from Qazvin exhibited the highest flavonoid content (810.7 μg quercetin equivalents (QE) g⁻¹ dry matter), anthocyanin content (2.2 μg cyanidin equivalents g⁻¹ fresh matter), and antioxidant activity (58.9%). Analysis of mean hypericin concentrations across plant organs in the four accessions showed that flowers had the highest concentration (3.84 mg g⁻¹), followed by leaves (2.25 mg g⁻¹) and flowering branches (1.49 mg g⁻¹). Stems contained the lowest concentration (0.68 mg g⁻¹). Simple correlation analysis revealed significant positive correlations between shoot yield and individual plant weight, plant height, and crown circumference. Antioxidant activity was also positively and significantly correlated with hypericin content.
Conclusion: The results identified accession A02 from Qazvin as superior in terms of morphological traits, flowering branch yield, and seed yield, whereas accession A03 from Qazvin showed the highest antioxidant activity. Accession A01 from Ardabil had the highest hypericin concentration in flowering branches. Accordingly, A02 was selected for cultivar introduction, while accessions A01 and A02 appear promising for further research aimed at developing a cultivar with high yield and phytochemical quality.
Improvement and breeding
Maryam Kiani; Mohammad Abdoli; Mehdi Ghabooli
Abstract
Background and objectives: Applying biotic and abiotic elicitors effectively enhances the biosynthesis and accumulation of valuable plant metabolites. This study aimed to assess the combined effects of yeast extract, salicylic acid, culture filtrate, and a cell homogenate derived ...
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Background and objectives: Applying biotic and abiotic elicitors effectively enhances the biosynthesis and accumulation of valuable plant metabolites. This study aimed to assess the combined effects of yeast extract, salicylic acid, culture filtrate, and a cell homogenate derived from Serendipita indica on the essential oil content, chemical composition, and selected physiological characteristics of lemon balm (Melissa officinalis L.).
Methodology: The experiment used a completely randomized design with 15 treatments and three replications in the research greenhouse at Malayer University in 2021. The experimental treatments included foliar application of distilled water (control), salicylic acid (320 mg L⁻¹), yeast extract (1 g L⁻¹), salicylic acid (320 mg L⁻¹) combined with yeast extract (1 g L⁻¹), salicylic acid (320 mg L⁻¹) combined with culture filtrate (½ v/v), yeast extract (1 g L⁻¹) combined with culture filtrate (½ v/v), salicylic acid (320 mg L⁻¹) combined with cell homogenate (40 or 80 mg L⁻¹), yeast extract (1 g L⁻¹) combined with cell homogenate (40 or 80 mg L⁻¹), salicylic acid (320 mg L⁻¹) combined with yeast extract (1 g L⁻¹) and cell homogenate (40 or 80 mg L⁻¹), salicylic acid (320 mg L⁻¹) combined with culture filtrate (½ v/v) and cell homogenate (40 mg L⁻¹), yeast extract (1 g L⁻¹) combined with culture filtrate (½ v/v) and cell homogenate (40 mg L⁻¹), and the combination of salicylic acid (320 mg L⁻¹), yeast extract (1 g L⁻¹), culture filtrate (½ v/v), and cell homogenate (40 mg L⁻¹). The elicitors were applied as foliar sprays to the aerial parts of lemon balm plants at the 40% flowering stage. Essential oil was extracted by hydrodistillation using distilled water and analyzed by gas chromatography–mass spectrometry (GC–MS). Essential oil content and chemical composition were determined, along with physiological traits, including photosynthetic pigments (chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids), proline, malondialdehyde, soluble sugars, total phenolic compounds, and total flavonoids. Pearson’s correlation coefficients (r) were calculated to assess the relationships among the measured traits.
Results: A total of 38 chemical compounds were identified in the essential oil extracted from the aerial parts of lemon balm. The major constituents of the essential oils were citronellal (6.1–13.5%), trans-carveol (5.0–10.6%), citral (3.9–10.1%), linalool (4.2–9.3%), and γ-3-carene (4.2–9.2%), respectively. The combined treatment consisting of salicylic acid (320 mg L⁻¹), yeast extract (1 g L⁻¹), culture filtrate (½ v/v), and cell homogenate (40 mg L⁻¹) produced the most pronounced increases in essential oil content and the concentrations of its major constituents. Compared with the control, this treatment increased essential oil content by 63% and increased citronellal, trans-carveol, citral, and linalool by 2.20-fold, 2.12-fold, 2.59-fold, and 2.21-fold, respectively. The lowest values for these traits were recorded in the control treatment. The elicitor treatments significantly affected soluble sugar, malondialdehyde, proline, and flavonoid levels. Correlation analysis revealed significant positive correlations at the 1% probability level between essential oil content and the major essential oil constituents linalool (r = 0.971**), trans-carveol (r = 0.983**), citronellal (r = 0.988**), and citral (r = 0.984**). In contrast, essential oil content was significantly negatively correlated with γ-3-carene (r = −0.990**). Heatmap analysis of the studied traits revealed a clear separation between the control and the combined biotic and abiotic elicitor treatments.
Conclusion: The results indicated that essential oil content and the concentrations of its major constituents in lemon balm were influenced by elicitors, including salicylic acid, yeast extract, culture filtrate, and cell homogenate. Overall, the combined application of two or more elicitors effectively enhanced essential oil production and the accumulation of its major constituents, particularly linalool, trans-carveol, citronellal, and citral, in lemon balm.
Phytochemistry (extraction, identification and measurement of active components)
Kobra Sepahvand; Abdolhossein Rezaei Nejad; Sadegh Mousavi-Fard; Reza Abolghasemi
Abstract
Background and Objectives: Drought stress is a shortage of available water that limits normal plant growth and delays life cycle completion; it affects growth and development by inducing biochemical, physiological, and morphological changes. Identifying effective management strategies ...
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Background and Objectives: Drought stress is a shortage of available water that limits normal plant growth and delays life cycle completion; it affects growth and development by inducing biochemical, physiological, and morphological changes. Identifying effective management strategies to alleviate drought stress can improve plant yield and quality. However, the effects of stress-mitigating agents such as nano calcium chloride and calcium carbonate on scented geranium (Pelargonium graveolens) characteristics have not been studied. Therefore, this study assessed the impact of foliar application of bulk and nano calcium chloride and calcium carbonate on selected antioxidant properties, essential oil content, and yield of scented geranium under drought stress.
Methodology: This experiment was conducted in 2023 at Lorestan University under greenhouse conditions using a factorial design in a completely randomized design (CRD) with four replications. The first factor was irrigation at two levels: no stress (80% of available water, control) and severe water deficit (20% of available water). The second factor was foliar application of calcium sources, calcium chloride and calcium carbonate in bulk and nano forms, each at concentrations of 5, 10, and 15 mM, along with a control (0 mM). In total, 13 treatments (26 treatment combinations) were evaluated. Rooted cuttings of Pelargonium graveolens were transplanted into 15-cm-diameter pots. After transplantation, plants were irrigated normally until full establishment. Foliar applications of calcium treatments were then initiated and applied every two weeks, 10 times in total. Drought stress treatments were imposed after the first foliar application according to scheduled irrigation intervals. At the end of the experiment (150 days after initiation), aboveground plant parts were harvested for biomass measurements. Fresh weights of leaves and stems were recorded immediately, and samples were then shade-dried to determine dry weights. Essential oils were extracted from dried, ground leaves by hydro-distillation in a Clevenger-type apparatus for three hours. To assess the activities of the antioxidant enzymes catalase (CAT), ascorbate peroxidase (APX), and superoxide dismutase (SOD), enzymes were extracted from frozen fresh leaf samples, and absorbance was read using a spectrophotometer.
Results: Analysis of variance showed that drought stress, calcium treatments, and their interaction significantly affected most evaluated traits (p < 0.01). Under 80% available water, 10 mM calcium carbonate increased catalase activity by 97.89% over the control (no foliar application). This increase was statistically similar to that from 15 mM nano calcium carbonate under the same irrigation condition or under 20% available water, which increased enzyme activity by 43.69%. Under 80% and 20% available water, 15 mM nano calcium carbonate increased superoxide dismutase activity by 72.34% and 15.48%, respectively, over the control. Under both irrigation levels, 15 mM nano calcium carbonate and nano calcium chloride increased flavonoid content by 50.37% and 39%, respectively, over the control. Under 80% available water, 15 mM calcium chloride increased essential oil yield by 56.86% over the control; this increase was statistically similar to that from 10 and 15 mM nano calcium chloride. Drought stress (20% available water) reduced essential oil yield. However, under drought conditions, 15 mM nano calcium carbonate increased essential oil yield by 80.95% over the control and was statistically similar to 10 and 15 mM nano calcium chloride.
Conclusion: Both bulk and nano calcium treatments affected enzymatic, antioxidant, and essential oil-related traits under both stress and non-stress conditions. Among the treatments, 15 mM nano calcium carbonate was the most effective for enhancing drought tolerance in scented geranium.
Biological effects of essential oils and extracts
Mounes Payamani; Mostafa Pirali Hamedani; Pedram Goodarzi; Mehdi Aghsami; Mahsa Sabernavaei
Abstract
Background and Objectives: Urinary tract infection (UTI) is one of the most common infections in humans and imposes a significant therapeutic and economic burden on healthcare systems. Although antibiotics remain the mainstay of treatment, the growing threat of antimicrobial resistance ...
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Background and Objectives: Urinary tract infection (UTI) is one of the most common infections in humans and imposes a significant therapeutic and economic burden on healthcare systems. Although antibiotics remain the mainstay of treatment, the growing threat of antimicrobial resistance highlights the need for alternative or adjunctive therapies. Stachys schtschegleevii has traditionally been used in Iranian folk medicine to treat infectious diseases. This study evaluated the therapeutic effect of the methanolic extract of the aerial parts of this plant on UTI in an animal model, with particular emphasis on reducing microbial load and urinary nitrite levels.
Methodology: A total of 500 g of powdered aerial parts of S. schtschegleevii was extracted with methanol by percolation at room temperature. The extract was concentrated and dried. Phytochemical screening was performed to identify the major bioactive constituents, including alkaloids, tannins, saponins, flavonoids, cyanogenic glycosides, and steroids. To assess anti-infective activity, 42 female Wistar rats weighing 200–250 g were randomly allocated to six groups: a healthy control (no infection or treatment), a negative control (infection without treatment), three treatment groups receiving extract doses of 500, 750, and 1000 mg/kg/day orally, and a positive control group treated with gentamicin (10 mg/kg/day intraperitoneally). UTI was induced by direct inoculation of 10⁵ CFU of Escherichia coli. Treatment continued for 21 days. Urine samples were collected on days 0 and 21 and analyzed for bacterial count and nitrite levels. Statistical analyses were performed using GraphPad Prism 5 software.
Results: Phytochemical analyses revealed tannins and flavonoids in the methanolic extract of S. schtschegleevii, whereas alkaloids, saponins, steroids, and cyanogenic glycosides were not detected. Pharmacological evaluation showed that after 21 days of treatment, rats receiving the extract at 500, 750, and 1000 mg/kg, as well as those treated with gentamicin, had significantly lower urinary bacterial counts than the negative control group. The greatest reduction in microbial load occurred in the group receiving 1000 mg/kg of the extract. Urinary nitrite assessment also confirmed a dose-dependent effect of the extract. In the 500 mg/kg group, two of seven rats tested negative; in the 750 mg/kg group, three tested negative; and in the 1000 mg/kg group, four rats tested negative for urinary nitrite. In contrast, only one rat in the gentamicin group remained nitrite-positive, whereas all rats in the negative control group remained nitrite-positive, indicating that the extract reduced UTI severity.
Conclusion: The findings suggest that the methanolic extract of Stachys schtschegleevii exhibits dose-dependent antibacterial activity, with the 1000 mg/kg dose showing the most promising results. Although its efficacy was lower than that of gentamicin, the extract showed significant therapeutic potential and could be considered an adjunct or preventive option in UTI management. Tannins are likely responsible for this effect. Future studies should isolate and purify the active constituents, investigate potential synergistic effects with antibiotics, and evaluate the pharmacokinetic and safety profiles of the extract.
Identification, introduction, ecology and ethnobotany
Narjes Hajiabadi; Mohamad Saghari; Fatemeh Jahanishakib
Abstract
Background and Objectives: Rangelands, as vital renewable resources, face escalating degradation. Cultivating native and medicinal plants constitutes a key restoration strategy that requires precise knowledge of species' ecological niches. Spatial distribution modeling, ...
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Background and Objectives: Rangelands, as vital renewable resources, face escalating degradation. Cultivating native and medicinal plants constitutes a key restoration strategy that requires precise knowledge of species' ecological niches. Spatial distribution modeling, particularly with Maximum Entropy (MaxEnt), offers a powerful tool for identifying critical environmental factors and predicting potential habitats. This study aimed to model the potential habitat and identify the key environmental factors influencing the distribution of the valuable medicinal plant Thymus vulgaris in the mountainous rangelands of Al-Qourat, South Khorasan Province, with implications for its conservation and sustainable use.
Methodology: Species occurrence data (n = 103) were systematically gathered through comprehensive field surveys within the study area. To ensure robust model evaluation, the dataset was partitioned into a training set (n = 72) and an independent validation set (n = 31). A total of 16 environmental predictors, categorized into four distinct groups—topography (elevation, slope, and aspect), climate (mean, maximum, and minimum temperature, and annual precipitation), soil properties (EC, pH, soil depth, gypsum content, organic matter, and sand, silt, and clay fractions), and anthropogenic pressure (distance to roads and villages)—were integrated and processed using Geographic Information Systems (GIS). Habitat suitability was modeled using the Maximum Entropy (MaxEnt) algorithm (version 3.3.3k), employing 10 Bootstrap iterations, 5,000 algorithm runs, and 10,000 background points. Model performance was statistically validated via the Area Under the Receiver Operating Characteristic curve (AUC). Furthermore, the Jackknife test and percent contribution analysis were implemented to quantify relative variable importance, while response curves were generated to delineate the species' optimal tolerance thresholds across environmental gradients. Finally, the predicted habitat suitability was classified into four distinct tiers.
Results: The MaxEnt model demonstrated excellent predictive accuracy (AUC = 0.93). Based on the Jackknife test and percent contribution analysis, elevation was the most significant predictor, accounting for 82.7% of the model's explanatory power. Other influential variables included aspect (4.4%), slope (3.5%), distance to villages (2.5%), maximum temperature (2.3%), and mean temperature (2.0%), whereas distance to roads was the least impactful variable (0.4%). Response curves indicated that species presence probability increases significantly with higher elevations (optimal range: 1970–2326 m), steeper slopes, and greater distances from anthropogenic disturbances (roads and villages). Regarding edaphic requirements, T. vulgaris thrives in soils with low salinity (optimal EC ≈ 0.57 dS/m), near-neutral pH (optimal ≈ 7.47), and a sandy loam texture (optimal composition: approximately 56.5% sand, 32.5% silt, and 11–11.5% clay). The resulting suitability map revealed that the highest habitat potential is concentrated in the northern sectors and high-altitude regions of the Al-Qurat rangelands, providing a spatial framework for the targeted conservation and sustainable management of this medicinal species.
Conclusion: This study confirms that Thymus vulgaris in the Al-Quroat rangelands is fully adapted to cold, sloping mountainous environments with well-drained, low-salinity soils. The marked sensitivity of this species' distribution to proximity to roads and human settlements indicates its high vulnerability to overexploitation and anthropogenic habitat degradation. The close agreement of these results with studies on other Thymus species in Iran suggests relatively consistent ecological patterns within this genus. The habitat suitability map and identified ecological indicators can serve as a valid document and practical guidance for natural resource managers and planners. It is suggested that effective steps be taken to protect the genetic resources and sustainable productivity of this valuable medicinal plant by implementing temporary protected areas in high-desirability habitats, establishing wise exploitation programs, and promoting domestic cultivation of this species in identified susceptible lands. Conducting similar studies by integrating different models and considering climate change scenarios for future projections of the species' distribution can complement the present study.
Agriculture and horticulture
Abuzar Hashempour; Ahmad Reza Dadars; Rahmatollah Gholami; Samaneh Asadi Sanam; Mahmoud Azimi
Abstract
Background and Objective: Olive (Olea europaea L.) is one of the most important horticultural crops in Iran and worldwide. Its oil plays a key role in promoting human health because of its high content of unsaturated fatty acids, particularly oleic acid, and its unique phenolic ...
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Background and Objective: Olive (Olea europaea L.) is one of the most important horticultural crops in Iran and worldwide. Its oil plays a key role in promoting human health because of its high content of unsaturated fatty acids, particularly oleic acid, and its unique phenolic compounds. Olive oil quality depends on various factors, including cultivar and climatic conditions. Because Iran has a diverse climate, this study evaluated the fatty acid profile, quality indices, and bioactive compounds of olive oil from the promising genotype Bn6 and the Konservolia cultivar in two regions: Tarom and Sarpol-e-Zahab.
Methodology: The research used a randomized complete block design with three replications in 2023 at two olive research stations in Tarom (Zanjan Province) and Sarpol-e-Zahab (Kermanshah Province). Olive fruits were harvested from genotype Bn6 and the Konservolia cultivar based on fruit color index, and oil was extracted at laboratory scale. Fatty acid composition was determined using gas chromatography (GC). We measured the following quality indices: acidity (as oleic acid percentage), peroxide value (milliequivalents of active oxygen per kg of oil), extinction coefficients K232 and K270, and total chlorophyll and carotenoid content. Total phenolic compounds were evaluated using the Folin–Ciocalteu method, and antioxidant capacity was assessed using the DPPH assay. Statistical analysis used a combined analysis of variance across locations in SAS 9.4 software, and means were compared using the LSD test.
Results: The combined analysis of variance showed that the genotype × environment interaction was significant for most fatty acids and some quality indices. Konservolia oil had higher oleic acid (63.47%), monounsaturated fatty acid (MUFA) (67.14%), MUFA/PUFA ratio (5.30), and oleic-to-linoleic acid ratio (5.44) than genotype Bn6. In contrast, genotype Bn6 had higher linoleic acid (36.73%) and a richer polyunsaturated fatty acid (PUFA) profile. The highest total phenol content (51.093 mg gallic acid per kg of oil) occurred in genotype Bn6 in Sarpol-e-Zahab, whereas the lowest (15.98 mg) occurred in the same genotype in Tarom. The highest antioxidant capacity (79.43%) occurred in Konservolia in Tarom and the lowest (13.54%) in the same cultivar in Sarpol-e-Zahab. According to International Olive Council (IOC) standards, Konservolia oil in both regions met the standard ranges for oleic acid (55–85%), palmitic acid (7–20%), and linoleic acid (2.5–21%). Genotype Bn6, however, did not meet the accepted standards for extra virgin olive oil in terms of oleic acid (below 55%) and linoleic acid (above 21%).
Conclusion: The Konservolia cultivar, with its stable phenolic compounds and compliance with IOC standards in both regions, is a more suitable option for producing oil with high oxidative stability and desirable nutritional value in both climates. Genotype Bn6 responds positively to heat stress by increasing phenolic compounds and therefore has special potential for warm regions. However, its oil does not comply with national and international standards regarding fatty acid composition. Therefore, given its high fruit yield and stable production in warm regions, it can be used in breeding programs and cultivar introduction for table olive production.
Improvement and breeding
Hamdollah Eskandari; Ashraf Alizadeh-Amraie
Abstract
Background and Objectives: Medicinal plants are important sources of bioactive compounds used in pharmaceutical, food, and health industries, but the quantity and quality of their active constituents are strongly affected by environmental conditions. Recent evidence indicates ...
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Background and Objectives: Medicinal plants are important sources of bioactive compounds used in pharmaceutical, food, and health industries, but the quantity and quality of their active constituents are strongly affected by environmental conditions. Recent evidence indicates that abiotic stress does not merely restrict plant growth; they also reprogram secondary metabolism through physiological and molecular regulatory networks. Focusing on drought, salinity, temperature, and radiation, this review examines the roles of redox regulation, hormonal crosstalk, transcriptional control, and biosynthetic pathways in shaping secondary-metabolite production. The main objective was to clarify the relationships among stress intensity, physiological responses, metabolic reprogramming, and the final quality of medicinal compounds.
Methodology: This study was conducted as an analytical review. Scientific literature was retrieved from Web of Science, Scopus, and Google Scholar using combinations of English keywords related to medicinal plants, abiotic stress, secondary metabolism, redox regulation, hormonal signaling, and biosynthetic pathways. The review mainly focused on peer-reviewed articles published from 2018 to 2024 that investigated relationships among abiotic stresses, physiological and molecular responses, and secondary-metabolite production in medicinal plants. Studies were selected when they were directly relevant to the review topic and provided physiological, biochemical, genomic, or metabolomic evidence useful for explaining the regulatory mechanisms of secondary metabolism. Purely descriptive studies or papers without a direct link to the quality of bioactive compounds were excluded. The selected findings were classified and compared according to stress type, response intensity, redox status, hormonal interactions, transcriptional control, biosynthetic-pathway regulation, and physiological and management implications. Evidence from different species and metabolite groups was then integrated to identify common response patterns as well as differences related to stress type, plant species, and response intensity. Finally, the relationships among redox signaling, hormonal regulation, gene expression, carbon allocation, and the biosynthesis of phenolic, terpenoid, and alkaloid compounds were synthesized into a conceptual framework linking environmental stress, plant physiological status, metabolic reprogramming, and active-compound quality.
Results: The reviewed evidence showed that secondary metabolism in medicinal plants is a dynamic system closely linked to plant physiological status. Drought, salinity, temperature, and radiation alter redox balance and, through controlled increases in reactive oxygen species, activate cellular signaling pathways and regulate the expression of key biosynthetic genes. These responses are strengthened by interactions among hormones such as jasmonic acid, salicylic acid, and abscisic acid and may redirect carbon flux toward the production of phenolic, terpenoid, and alkaloid compounds. Metabolic responses to stress were clearly nonlinear: mild stress often increased active-compound concentrations, whereas severe stress reduced metabolite-production capacity by limiting photosynthesis, energy supply, and carbon precursors. Morphological adjustments, including an increased glandular trichome density, may also enhance the capacity to produce certain medicinal compounds. Across studies, medicinal quality emerged as the result of interactions among photosynthetic status, resource allocation, redox and hormonal networks, and genetic capacity; therefore, similar stress intensity did not necessarily produce the same response across species or developmental stages. An increase in individual metabolite concentration did not necessarily translate into a higher total yield of the active compound because it could coincide with reduced biomass. Overall, controlled stress, appropriate timing of agronomic practices, and elicitor application were most effective when metabolic stimulation occurred without a severe reduction in growth and biomass.
Conclusion: The effects of environmental stress on medicinal-compound production depend on stress type and intensity, genotype, developmental stage, and photosynthetic capacity. Mild stress can enhance secondary-metabolite accumulation through redox signaling, hormonal pathways, and activation of biosynthetic genes, whereas severe stress can have the opposite effect by restricting photosynthesis and carbon supply. Therefore, active-compound concentration should be assessed alongside biomass and total metabolite yield. Determining the appropriate stress threshold and timing can serve as a scientific basis for the targeted use of controlled stress and elicitors to improve medicinal-plant quality.
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