Journal of Medicinal Plants Biotechnology

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 Biodiversity plays a major role in the well-being of the world population by contributing to human livelihood and development. According to WHO reports, about 80% of the world's population still relies on herbal medicines. Today, most of the drugs are self-contained medicinal plants. Natural substances have long served as sources of therapeutic drugs, such as digitalis (from foxglove), ergotamine (from infected rye), salicylates (willow bark) being classic examples. Drug discovery from natural sources includes a multifaceted approach by combining botanical, phytochemical, biological and molecular techniques. Therefore, drug discovery based on medicinal plants is still an important and undiscovered area, research in this issue leads to important results in line with medicinal goals. The decrease in biodiversity is the result of the increase in global population, rapid industrialization, excessive deforestation, overexploitation of natural resources, Pollution and ultimately global climate change. Preserving plant biodiversity is important for creating structural diversity and main compounds in the future for the sustainable development of human civilization. This issue becomes more important for

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