Journal of Medicinal Plants Biotechnology

Abstract In light of the growing demand for medicinal plants and their increasing significance in global society, this study examined the essential oils composition and phenolic content in the flowers and leaves of Stachys schtschegleevi. Plant samples were collected from the Jolfa region, and the essential oils were extracted using a Clevenger apparatus. The chemical composition of the essential oils was analyzed using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The results showed that the percentage of essential oil in the flower organs was 39% higher than in the leaves. Analysis of the essential oils identified 61 compounds in the flowers (98.39% of the total) and 49 compounds in the leaves (98.73% of the total). The dominant compounds in the flower organs were germacrene D (20.69%), α-cadinol (9.51%), α-muurolene (7.16%), n-hexadecanoic acid (5.93%), thymol (5.41%), spathulenol (4.77%), α-pinene (4.62%) and β-pinene (4%). The dominant compounds in Pulak leaf essential oil were found to be α-pinene (12.98%), germacrene D (11.92%), α-cadinol (7.9%), thymol (6.91%), n-hexadecanoic acid (4.82%), spathulenol (4.44%) and α-muurolene (4.22%). Evaluation of the phenolic compounds showed that the total phenol and flavonoid content in the flowers (81.8 and 3.5 mg/ g of dry extract, respectively) was higher than in the leaves (56.1 and 3 mg/g of dry extract, respectively). Therefore, due to its higher essential oil percentage and greater richness in phenolic compounds, the flower organ of Stachys schtschegleevi is considered more suitable than the leaf organ for industrial applications, particularly in the field of essential oil extraction.

Abstract To investigate the effect of proline and gamma-aminobutyric acid on the quantitative and qualitative traits of medicinal plant chamomile (Matricaria chamomilla L.) under water deficit stress, an experiment was conducted according to split plots design with a completely randomized block arrangement with four replications during the spring and summer of 2024 in the research greenhouse at the University of Zanjan. The main factor consisted of two irrigation levels (70 and 100% of field capacity) and the subplots included foliar applications of two levels of proline (0.5 and 1 mM), gamma-aminobutyric acid (0.5 and 1 mM) and control treatment (distilled water).
The results showed that the highest chlorophyll a content (1.40 mg/g fresh weight) was achieved under 100% field capacity irrigation combined with 1 mM proline. Foliar application of 0.5 mM proline under 70% irrigation level resulted in the highest phenolic content (4.78 mg gallic acid/g dry weight) and the greatest total antioxidant activity (51.75%). The maximum flavonoid content (1.49 mg quercetin/g dry weight) was observed with 0.5 M GABA treatment. Additionally, the highest thousand-seed weight (148 mg) was recorded under full irrigation (100% field capacity) with 1 mM proline, compared to the control. Overall, the combined application of 0.5 mM proline and GABA was most effective in mitigating the adverse effects of drought stress on chamomile.

Abstract Plants synthesize a huge variety of secondary metabolites with complex chemical composition that not only have medicinal value but are also important to deal with biotic and abiotic stress conditions. The aim of current study was to investigate the impact of heat shock treatment on the production of secondary metabolites in callus obtained from of Echinacea purpurea plant. For this purpose, seeds were grown on MS medium. Then root explants were prepared from 45 days seedlings and transferred to MS medium containing 0/5 and 1 mg/L 2,4-D and Kin. Heat shock treatment at 35 °C for different time durations (10, 20, 30, 40, 50 and 60 min) was daily applied on 2 months old callus. After a week, the samples were collected and different biochemical analysis was performed. The results showed that the highest amount of total phenol, total flavonoid, soluble suger, MDA, chicoric acid, chlorogenic acid and caffeic acid was observed in samples that were treated for 60 min at 35 °C. On the other hand, the present data revealed that heat shock treatment caused a significant increase in catalase and peroxidase activity, but there was not any significant difference between different treatments. As a conclusion, heat shock treatment can be used as a new method to enhance secondary metabolites production in Echinacea in tissue culture contion.

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