چكيده لاتين
The plant Hyoscyamus niger L., a member of the Solanaceae family, is of significant pharmaceutical importance due to its production of tropane alkaloids such as hyoscyamine and scopolamine. This study aimed to investigate the effect of different concentrations of putrescine on the enzymatic and non-enzymatic antioxidant systems and the production of valuable secondary metabolites in H. niger. To achieve this, the seeds of H. niger were cultured on ½ MS medium for germination. After seedling development, suitable explants were transferred to culture media supplemented with various concentrations of putrescine (0, 0.25, 0.5, 1, 2, and 3 mM) for three weeks. The results indicated significant changes compared to the control in the activities of catalase (CAT), ascorbate peroxidase (APX), and superoxide dismutase (SOD), as well as in the levels of H₂O₂ and MDA. Additionally, the contents of proline, total phenolics, flavonoids, flavonols, anthocyanins, chlorophyll a and b, carotenoids, total antioxidant capacity, fresh weight, dry weight, and total alkaloids were also affected by the putrescine treatments. Treatment with low to moderate concentrations of putrescine (0.25–2 mM) significantly enhanced growth parameters, improved physiological status, promoted the accumulation of phenolic compounds and alkaloids, and increased antioxidant enzyme activities. In contrast, a higher concentration (3 mM) resulted in a decline in these parameters. These findings suggest that putrescine induces various changes in cell structure and metabolism, both directly and indirectly through oxidative stress. By influencing the enzymatic and non-enzymatic antioxidant defense systems, putrescine triggers the biosynthetic pathways of alkaloids and phenolic compounds, leading to their accumulation in H. niger plantlets. Overall, this study demonstrates that applying putrescine at optimal concentrations can effectively enhance growth and secondary metabolite production in H. niger, providing a promising strategy for improving the in vitro mass production of alkaloids in this medicinal plant.
