Dose- and time-dependent elicitation of hypericin and hyperforin in Hypericum perforatum adventitious roots using metallic and carbon-based nanoparticles
摘要
Nanoparticles (NPs) have emerged as novel elicitors for enhancing the production of secondary metabolites in medicinal plants. However, the comparative effects of different NP types on Hypericum perforatum adventitious roots remain unexplored. This study aimed to compare the elicitation effects of graphene oxide (GO), copper oxide (CuO), and silicon dioxide (SiO₂) nanoparticles on the accumulation of hypericin and hyperforin in H. perforatum adventitious roots. A factorial experimental design was employed with three NP types, four concentrations (25–250 mg/L), three exposure durations (2, 4, and 6 days), and three replicates per treatment. Biomass (fresh and dry weight) and secondary metabolite levels were quantified using HPLC. Data were analyzed using three-way ANOVA followed by Tukey’s HSD test (p < 0.05). A time-dependent decline in biomass was observed across all NP types. SiO₂ NPs promoted transient early growth at day 2 (especially at 200 mg/L), but overall biomass declined by day 6, with CuO inducing the most severe inhibition. GO NPs at 50 mg/L for 6 days increased hyperforin from 0.097 µg/g DW (control) to 0.271 µg/g DW (2.8-fold), and hypericin from 0.152 µg/g DW to 0.230 µg/g DW (1.5-fold). Significant three-way interactions were observed between NP type, concentration, and duration (p < 0.001), indicating differential regulation and a trade-off between biomass reduction and metabolite elicitation via stress-induced pathways. This first comparative report demonstrates that NPs can serve as tunable biotechnological tools for targeted phytochemical enhancement, offering a promising strategy to improve the production of antiviral and antidepressant compounds in H. perforatum.