Characterization and Toxicity of Hypoxoside Capped Silver Nanoparticles

Area of Science:

• Green Chemistry and Nanotechnology
• Phytochemistry and Bioreduction
• Materials Science

Background:

• Plant extracts contain phytochemicals that can act as reducing agents in nanoparticle biosynthesis.
• Hypoxis hemerocallidea (HE) extract contains significant amounts of hypoxoside (HP), a norlignan diglucoside.
• Pharmacologically inactive phytochemicals can still play crucial roles in nanoparticle synthesis.

Purpose of the Study:

• To isolate hypoxoside (HP) from Hypoxis hemerocallidea (HE) extract.
• To biosynthesize silver nanoparticles (AgNPs) using both the HE extract and isolated HP.
• To characterize the synthesized AgNPs and evaluate their antimicrobial and anticancer activities.

Main Methods:

• Isolation of hypoxoside from HE extract.
• Biosynthesis of silver nanoparticles using HE extract (HE-AgNPs) and isolated HP (HP-AgNPs).
• Physicochemical characterization using techniques like Transmission Electron Microscopy (TEM).
• Evaluation of antimicrobial activity against Escherichia coli and Salmonella enterica.
• Assessment of anticancer activity against U87 and U251 glioblastoma cell lines.

Main Results:

• TEM revealed distinct sizes: HE-AgNPs (24.3 ± 4 nm) and ultra-small HP-AgNPs (3.9 ± 1.6 nm).
• HE-AgNPs showed strong bactericidal effects with a Minimum Inhibitory Concentration (MIC) of 1.95 µg/mL.
• HP-AgNPs exhibited potent cytotoxicity against U87 and U251 cells (IC50: 0.20 and 0.55 µg/mL, respectively).
• HP-AgNPs demonstrated selectivity towards both glioblastoma cell lines tested, while HE-AgNPs were selective to U87.

Conclusions:

• Hypoxoside acts as an effective standalone reducing and capping agent for synthesizing ultra-small, monodispersed AgNPs.
• The synthesized AgNPs possess significant antimicrobial and anticancer properties.
• Isolated hypoxoside offers a promising route for developing novel nanomaterials with enhanced biological activities.