Silver nanoparticles synthesised using endophytic fungus Calonectria eucalypti from medicinal plant axifraga stolonifera and their bioactivity

Abstract

Silver nanoparticles (AgNPs) are widely used but traditional synthesis methods are energy-intensive and polluting. Biosynthesis offers an eco-friendly approach, yet studies on medicinal plant endophytic fungi remain scarce. This work reports the isolation and characterization of AgNPs synthesized by endophytic fungi from Saxifraga stolonifera, along with an assessment of their bioactivities, including antimicrobial, anticancer, and antioxidant effects. AgNPs were biosynthesized using the aqueous extract of the fungus HECL10, which was identified as Calonectria eucalypti. The HECL10-AgNPs were characterised by UV‒vis spectroscopy, SEM, EDS, TEM, FT-IR and zeta potential analysis. The drug susceptibility experiments illustrated that HECL10-AgNPs exhibited potent antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans. Additionally, the cytotoxicity assays revealed that the HECL10-AgNPs exhibited prominent anticancer effects on the A549, A375, HeLa and HepG2 cell lines. Notably, the scavenging rates of HECL10-AgNPs at 200 µg/mL against DPPH, ABTS, and OH radicals were 90.49 %, 60.38 %, and 38.76 %, respectively. Compared to the H₂O₂-induced model group, the treatment of HECL10-AgNPs at concentrations of 25.00 µg/mL significantly reduced intracellular ROS levels in HaCaT cells by 44.8 %, and enhanced the activity of SOD, CAT, and GSH by 106.7 %, 2036.1 % and 43.5 %. The results demonstrated that HECL10-AgNPs possessed potent antioxidant properties. These findings revealed the potential for synthesising AgNPs using endophytic fungi from medicinal plants and emphasised the promise of HECL10-AgNPs as a multifunctional nanomedicine for biomedical applications.