The effect of silver nanoparticles on the growth and antioxidants of transgenic hairy roots in hyssop (Hyssopus officinalis, H. angustifolius)

Background: Nowadays, biotechnological methods such as transgenic hairy root culture and application of elicitors have become an attractive source for secondary metabolites production. Hyssop species (Hyssopus spp.) having active ingredients including antioxidants such as phenolics, in this plant have shown anti-mutagenic, anti-carcinogenic and antiglycemic effects. Objective: The present study was conducted to investigate the effect of silver nanoparticles on the growth and antioxidants of transgenic hairy root in two Hyssopus species including H. officinalis and H. angustifolius. Methods: In this experiment, we used silver nanoparticles concentrations of 0, 0.1, 0.2, 0.3 mg/l on transgenic hairy roots and Agrobacterium rhizogenes ATCC15834 strain for induction of hairy roots. Extraction of the samples were performed following ultrasonic method. Total phenolics content were determined using spectrophotometry. The antioxidant activity (AOA) of the extract were evaluated through 2, 2-dipheny l-1-picryl-hydrazy l (DPPH) method. Results: The results showed that silver nanoparticles as an elicitor had significant effect on the measured traits. The highest dry weight and fresh weight of the transgenic hairy roots were observed as much as 3.8 and 16 g/l in H. angustifolius and 3.2 and 14 g/l in H. officinalis, respectively. Which were caused by silver nanoparticles at the concentration of 0.1 mg/l, The amount of total antioxidants in H. angustifolius and H. officinaliswere 90.81% and 89.84%, respectively. In this study, we could observe relationship between antioxidant activity and plant phenolic content. Conclusion: In general, we found that 0.1 mg/l silver nanoparticles could improve the growth of transgenic hairy roots and increase their phenolics and antioxidants content.