Abstract
This study aimed at preparing and characterizing thymol, eugenol, and
piperine-loaded poly(D,L-lactic-co-glycolic acid) nanoparticles and
evaluating the effect on inflammatory mediators secretion and apoptosis in Raw
264.7 macrophage cells. Nanoparticles were produced by the solvent evaporation
technique. Dynamic light scattering and scanning electron microscopy were used
to study the physicochemical characteristics. Raw 264.7 macrophage cells were
used as a model for in vitro assays. The
2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium assay
was used to determine the cytotoxicity of the formulated nanoparticles. An
annexin V apoptosis detection kit was used to assess apoptosis. Nitric oxide
production was determined using the Griess reagent, and the inflammatory
mediators level was evaluated with Th1/Th2 cytokine and fluorometric
cyclooxygenase kits. The loaded nanoparticles showed a particle size around
190 nm with a low polydispersity between 0.069 and 0.104 and a zeta
potential between–1.2 and–9.5 mV. Reduced cytotoxicity
of nanoparticles compared to free molecules against Raw 264.7 macrophage cells
was observed and seemed to occur through a mechanism associated with apoptosis.
A decrease in cyclooxygenase enzyme activity with an increasing concentration
was observed. Both free molecules and nanoparticles showed their capacity to
modulate the inflammatory process mostly by inhibiting the investigated
inflammatory cytokines. The data presented in this study indicate that thymol
and piperine-loaded poly(D,L-lactic-co-glycolic acid nanoparticles could
serve as a novel anti-inflammatory colloidal drug delivery system with reduced
toxicity. However, further study should be considered to optimize the
formulation’s loading capacity and thereby probably enhance their
bioactivity in treating inflammatory diseases.
Key words
thymol - piperine - nanoparticles - anti-inflammatory activity - cytokines - apoptosis
