Eco-friendly synthesis of silver nanoparticles: unraveling their influence on callus proliferation, secondary metabolite production, and antioxidant activities in Ruta chalepensis L.

This study investigates the potential of biologically synthesized silver nanoparticles (AgNPs) with Maerua crassifolia leaf extracts to enhance the production of bioactive compounds in Ruta chalepensis callus, alongside evaluating biomass growth, phytochemical content, antioxidant enzymes, and activities. AgNPs were characterized using transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), and UV-visible spectroscopy (UV), then introduced at various concentrations (0, 7.5, 15, 30, and 60 mg/L) into Murashige and Skoog (MS) media supplemented with 10 µM 2,4-Dichlorophenoxyacetic acid (2,4-D) and 1.0 µM 6-benzyladenine (BA). Notably, the incorporation of 30 mg/L of AgNPs into the MS medium resulted in the highest callus fresh weight (FW: 4.13 g) and callus dry weight (DW: 0.298 g) compared to both the control and other AgNPs treatments. Furthermore, this concentration exhibited elevated levels of protein (24.95 mg/ml), phenolic (90.58 mg GAE/g DW), tannin (18.57 mg TAE/g DW), flavonoid (70.97 mg QE/g DW), and flavonol (27.5 mg RE/g DW). Additionally, the enhanced antioxidant enzyme activities, including catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX) (18.81, 5.08, and 9.48 U/mg protein, respectively) were also observed at the same treatment. The 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS: 88.03%) assay and the 2,2-diphenylpicrylhydrazyl (DPPH: 85.25%) assay also showed increased activity at 30 mg/L of AgNPs, while the ferric reducing antioxidant power (FRAP) assay indicated maximum activity (33.82 mg AAE/g DW) at 60 mg/L of AgNPs. Moreover, the application of AgNPs at 30 mg/L resulted in of higher concentrations of quercetin (119.15 µg/g DW), rutin (192.96 µg/g DW), and hesperidin (219.87 µg/g DW). In conclusion, the results indicate that incorporating green AgNPs has a positive influence on the phyto-biochemical profile of R. chalepensis callus cultures, leading to enhanced levels of antioxidants and phytochemicals.

Biologically synthesized AgNPs from Maerua crassifolia enhance bioactive compound synthesis in R. chalepensis callus, characterized using advanced techniques, positively impacting biomass growth, phytochemical content, antioxidant enzymes, and activities.