Mechanical Grinding-Derived Turmeric Rhizome Nanoparticles (Curcuma longa L.): Characterization and Comparative Antibacterial Efficacy

Abstract

Antimicrobial resistance, especially to in Staphylococcus aureus (S.aureus), is a serious global health problem because of the bacteria's ability to resist treatment for various infections and the high level of bacterial resistance. This study investigated the physicochemical characterization and antibacterial activity of turmeric (Curcuma longa L) rhizome powder and its derived nanoparticles prepared via mechanical milling. The nanoparticles were synthesized through top-down mechanical milling with varying grinding durations (30, 60, 90, and 120 min). Comprehensive characterization was performed using Scanning Electron Microscopy with Energy Dispersive X-ray analysis (SEM-EDX), X-ray Diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), and Differential Scanning Calorimetry (DSC). Particle size distribution and active compound content (curcuminoid) were quantitatively determined. Antibacterial efficacy was evaluated against S.aureus. Based on particle size analysis (PSA) and particle morphology (SEM), the optimal grinding duration was 60 min, producing fine, uniform, agglomeration-free nanoparticles (117.16 nm). The EDX results showed the best elemental composition at 30 minutes. DSC analysis showed the best thermal stability of the nanoparticles ground for 30 min, while FTIR showed the best-preserved curcuminoid structure at 60 min. Grinding duration affected ash content, with the optimum result (6.19%) also found at 60 min. Antibacterial activity showed the lowest % MIC (0.905%) at 24 hours with a grinding duration of 30 min, and there was a significant effect (p<0.05) between the grinding duration and the inhibition zone of S. aureus. This study provides a scientifically rigorous, mechanistically grounded foundation. The formulations may offer improved  with significantly enhanced biopharmaceutical performance compared with conventional turmeric preparations.