Overproduction of tropane alkaloids in transgenic Hyoscyamus reticulatus hairy roots L. elicited by silicon dioxide nanoparticles and precursor feeding by phenylalanine and putrescine

The use of herbal medicines is expanding rapidly, and reputable pharmaceutical companies are increasing the proportion of effective herbal compounds in the production of drugs used to treat conditions such as cancer and neurological disorders. The commercial-scale production of these natural metabolites by plants remains limited, necessitating the application of modern technologies to enhance their yield. In the present study, the effects of various concentrations of silicon dioxide nanoparticles (SiO₂ NPs) as an elicitor (0, 100, and 200 mg/L) and different precursors (no precursor, phenylalanine, and putrescine at 3 mM) on the growth and phytochemical traits of Hyoscyamus reticulatus hairy roots were investigated. Hairy roots gradually appeared from the wound sites two weeks after inoculation. The highest fresh weight (FW) (3.57 g) was observed in the putrescine precursor treatment, while the maximum dry weight (DW) (0.73 g) was recorded in the control group. The highest total phenolic content (TPC) (7.79 mg GA/g FW) was observed with the putrescine precursor, while the highest total flavonoid content (TFC). (1.79 mg QUE/g FW) was obtained with the phenylalanine precursor, both in the absence of the elicitor. HPLC analysis revealed that the highest levels of hyoscyamine (165.4 µg/g DW) and scopolamine (91.3 µg/g DW) were detected in hairy roots treated with 200 mg/L SiO₂ NPs combined with putrescine precursor. These findings suggest that the combined use of elicitors and precursor feeding in transgenic hairy root cultures of H. reticulatus can significantly enhance the production of tropane alkaloids, such as hyoscyamine and scopolamine.