Characterization of silver nanoparticles produced by green synthesis and its effects on root growth and the accumulation of iridoid, secoiridoid, and xanthones in Gentiana lutea L. root cultures

In this study, it was carried out to determine the effects of green synthesis silver nanoparticles (SNPs) on the root growth and secondary metabolite accumulation of roots in yellow gentian (Gentiana lutea L.). For this purpose, SNPs at different concentrations (4, 8, 12, and 16 mg/l) were applied to the roots grown in vitro for 2, 4, and 6 days. After harvest, roots were evaluated in terms of fresh root weight, dry root weight, root growth index, and some metabolite contents belonging to groups of iridoid, xanthone, and secoiridoids. As a result of the study, SNPs applied at 4 and 8 mg/l concentrations to roots increased the root fresh weight and growth index compared to the control while 16 mg/l of SNP decreased all the root growth criteria. SNP applications significantly changed the metabolite accumulation according to their concentrations and application times. The highest values were obtained from 16 mg/l SNP applied for 4 days for loganic acid and sweroside 4 mg/l SNP for 6 days for amarogentin and 16 mg/l SNP applied for 6 days for gentiopicroside. On the other hand, it was determined that the highest values in terms of swertiamarin and isogentisin were obtained from the control group roots and SNP applications had an inhibitory effect on the accumulation of these metabolites. Consequently, SNP applications significantly changed root growth and metabolite accumulation in yellow gentian root cultures depending on their concentration and harvest times. It has been also determined that SNP applications can be used successfully for the accumulation of loganic acid, sverositine, amarogentin and gentiopicroside.