RESUMO
Ammi visnaga L. is an enriched medicinal plant with medicinally important compounds. Two types of nanoparticles (NPs) including silica (SiO2) and graphene oxide bound with SiO2 (GO-SiO2) NPs at different concentrations (0, 15, 25 mg L-1) were used as elicitors to investigate their effects on callus morphology, H2O2 content, total phenolic content (TPC), total flavonoids content (TFC), ferric reducing/antioxidant power (FRAP), and few antioxidant enzymes such as catalase (CAT), guaiacol peroxidase (GPX), superoxide dismutase (SOD), ascorbate peroxidase (APX), and polyphenol oxidase (PPO) in the callus cultures of A. visnaga. The effects of elicitation of both NPs on calli were observed using a scanning electron microscope (SEM). The 15 mg L-1 concentration of GO-SiO2 NPs produced the highest TPC (193.3 mg GAE g-1 FW), CAT (13.1 U mg-1 Protein), GPX (0.0089 U mg-1 Protein), and APX (0.079 U mg-1 Protein). Whereas, the maximum content of H2O2 (0.68 µmol g-1 FW), FRAP (0.0092 µmol mg-1), and TFC (62.27 mg QE g-1 FW) was observed at 25 mg L-1 and 15 mg L-1 of SiO2 NPs, respectively. Conclusively, in the callus culture of A. visnaga, the 15 mg L-1 concentration of GO-SiO2 NPs was the most suitable dosage for enhancing the enzymatic antioxidant activities (CAT, GPX, APX) and TPC, rather than SiO2 NPs.
