Effects of graphene oxide incorporated with silicon dioxide on some secondary metabolites of Levisticum officinale Koch. through callus culture

Considering the importance of medicinal compounds in medicinal plant species, the production of secondary medicinal metabolites through callus cultivation and subsequent elicitation is economical and time-saving. Levisticum officinale Koch. is one of the valuable indigenous rangeland plants of Iran, which has many medicinal and industrial properties. This study was carried out to optimize callus induction and the effects of different concentrations of GO-SiO2 on the amounts of different secondary metabolites and antioxidant activity under callus culture. For callus induction, the hypocotyl explants were transferred to Murashige and Skoog (MS) culture medium containing different growth regulators. Analysis of variance showed that different plant growth regulators had a significant effect on The MS media supplemented with 1.5 mg/L 2,4-D + 0.025 mg/L (NAA) + 0.5 Kin showed the best percentage of callus production (95%). In order to investigate the effect of the elicitor on the amount of secondary metabolites in the callus, different concentrations of GO-SiO2 (0, 5, 10 and 20 mg/L) were chosen as elicitors. The selected nanoparticle showed positiveand stimulatory effects on the amount of secondary metabolites and antioxidant activity in the callus. The highest content for total phenolics (47.26 mg GAE/g FW), total flavonoids (28.06 mg QE/g FW) and antioxidant activity FRAP (0.096 μ mol /g extract) was observed under 10 mg/L of GO-SiO2. The highest contents for total flavonols (8.18 mg QE /g FW), H2O2 (5.09 μmol/g FW) and total anthocyanin (0.07 μmol/g FW) were observed under 20 mg/L GO-SiO2 treatment. The highest level of carotenoid content (28.11 mg/g FW) and chlorophyll (23.58 mg/g FW) were observed under 5 mg/ L GO-SiO2. The results of this study can be used to optimize the production of secondary medicinal metabolites in this valuable medicinal plant. According to the results of this study, the application of graphene oxide nanopaGO-SiO2 (10 mg/L) could be used for the highest production of total phenolics and flavonoids as well as increasing the antioxidant activity through callus culture in this valuable plant of Iran.