Chitosan Nanoparticle Encapsulation of Thymus Capitatus Essential Oil: In Vitro Release, Antioxidant, Antibacterial Activity and Cytotoxicity in MDA-MB-231 Cells

Thymus capitatus (Th. Ca) is known to treat mouth ulcers and respiratory infections in Cyprus. However, antioxidant, antibacterial, and cytotoxic potential of Th. Ca. EO on MDA-MB-231 cells and its' encapsulation into nanoparticles has not been well studied. Therefore, we aimed to analyze the antioxidant, antibacterial, cytotoxic potential, loading efficiency, and in vitro release profile of both Th. Ca. EO and Chitosan Nanoparticle (Ch. Np) - Th. Ca. EO. GC-MS analysis revealed 53.97% carvacrol, 14.53% borneol, and 12.09% sabinene presence in EO. The loading efficiency of Th. Ca. EO into Ch. Np. was calculated as 35.27% and the in vitro release profile reached a maximum of 68% in pH 7 for two weeks. The Minimum Inhibitory Concentration (MIC) assay showed that E. coli had an MIC₅₀ of 0.3215 mg/ml while B. subtilis had an MIC₅₀ of 0.5304 mg/ml. The antioxidant activity of the EO was assessed by performing a DPPH assay with an IC₅₀ = 440 μg/ml. Trypan Blue Assay revealed that 60 µg/ml Th. Ca. EO significantly reduced the cell viability of MDA-MB-231 cells by 10.7% at 48h and 20.06% at 72h. Overall, Ch. Np. - Th. Ca. EO has shown a promising formulation for the pharmaceutical industry.