Synthesis and Characterization of Sulfur Nanoparticles of Citrus limon Extract Embedded in Nanohydrogel Formulation: In Vitro and In Vivo Studies

Abstract

The study aimed to synthesize non-noxious, clean, reliable, and green sulfur nanoparticles (SNPs) from <i>Citrus limon</i> leaves. The synthesized SNPs were used to analyze particle size, zeta potential, UV-visible spectroscopy, SEM, and ATR-FTIR. The prepared SNPs exhibited a globule size of 55.32 ± 2.15 nm, PDI value of 0.365 ± 0.06, and zeta potential of -12.32 ± 0.23 mV. The presence of SNPs was confirmed by UV-visible spectroscopy in the range of 290 nm. The SEM image showed that the particles were spherical with a size of 40 nm. The ATR-FTIR study showed no interaction, and all the major peaks were preserved in the formulations. An antimicrobial and antifungal study of SNPs was carried out against Gram-positive bacteria (<i>Staph. aureus</i>, <i>Bacillus</i>), Gram-negative bacteria (<i>E. coli</i> and <i>Bordetella),</i> and fungal strains (<i>Candida albicans)</i>. The study showed that <i>Citrus limon</i> extract SNPs exhibited better antimicrobial and antifungal activities against <i>Staph. aureus</i>, <i>Bacillus</i>, <i>E. coli</i>, <i>Bordetella</i>, and <i>Candida albicans</i> at a minimal inhibitory concentration of 50 μg/mL. Different antibiotics were used alone and in combination with SNPs of <i>Citrus limon</i> extract to evaluate their activity against various strains of bacteria and fungal strains. The study showed that using SNPs of <i>Citrus limon</i> extract with antibiotics has a synergistic effect against <i>Staph.aureus</i>, <i>Bacillus</i>, <i>E. coli</i>, <i>Bordetella</i>, and <i>Candida albicans</i>. SNPs were embedded in nanohydrogel formulations for in vivo (wound healing) studies. In preclinical studies, SNPs of <i>Citrus limon</i> extract embedded within a nanohydrogel formulation (NHGF4) have shown promising results. To be widely used in clinical settings, further studies are needed to evaluate their safety and efficacy in human volunteers.