Tropane alkaloids continue to be commercially extracted from medicinal plants, making them the sole source of these compounds Hyoscyamus reticulatus L. is particularly rich in tropane alkaloids like hyoscyamine and scopolamine, which are valued for their mydriatic, anticholinergic, and sedative effects. In this study, hairy roots of H. reticulatus were developed through inoculation with the Agrobacterium rhizogenes strain A4. These hairy roots were utilized to assess the impact of L-ornithine precursor feeding at concentrations of 0, 1, 2, and 3 mM, along with varying amounts of Aspergillus niger fungal extract (0, 1, and 1.5 mg/L) as a bio-elicitor. The investigation focused on parameters such as fresh and dry weight, total phenolic and flavonoid content, antioxidant activity, antioxidant enzyme activity, total alkaloids, and tropane alkaloids. Results indicated that increasing L-ornithine concentrations led to enhanced fresh and dry weights of the hairy roots, peaking at 3 mM. The highest total phenolic content was recorded with 1.5 mg/L of A. niger extract, while the control showed the lowest levels. Although the interaction effect on total flavonoid content was not significant, both 2 mM L-ornithine and 1.5 mg/L A. niger extract independently increased flavonoid levels in the hairy roots. Various concentrations of L-ornithine and A. niger enhanced antioxidant capacity, with the highest enzyme activities observed at 3 mM L-ornithine and 1.5 mg/L A. niger. The maximum production of hyoscyamine and scopolamine was noted at these concentrations, showing increases of 4.5 and 5.2 times, respectively, compared to the control sample.
Karami et al. (Mon,) studied this question.