Author ORCID Identifier

Document Type



Available under a Creative Commons Attribution Non-Commercial Share Alike 4.0 International Licence


Atomic, Molecular and Chemical Physics, Colloid chemistry, Biophysics, Nano-materials, Toxicology

Publication Details

“In vitro toxicological evaluation of mesoporous silica microparticles functionalised with carvacrol and thymol”, Cristina Fuentes, Ana Fuentes, Hugh J.Byrne, José Manuel Barat, María José Ruiz, Food and Chemical Toxicology, 160, 112778 (2022)

Author's accepted version


The cytotoxicity of carvacrol- and thymol- functionalised mesoporous silica microparticles (MCM-41) was assessed in the human hepatocarcinoma cell line (HepG2). Cell viability, lactate dehydrogenase (LDH) activity, reactive oxygen species (ROS) production, mitochondrial membrane potential (ΔΨm), lipid peroxidation (LPO) and apoptosis/necrosis analysis were used as endpoints. Results showed that both materials induced cytotoxicity in a time and concentration-dependent manner, being more cytotoxic than free essential oil components and bare MCM-41. This effect was caused by the cell-particle interactions and not from degradation products released to the culture media, as demonstrated in the extract dilution assays. LDH release was seen to be a less sensitive endpoint than the MTT (thiazolyl blue tetrazolium bromide) assay, suggesting impairment of the mitochondrial function as the primary cytotoxic mechanism. In vitro tests on specialised cell functions showed that exposure to sublethal concentrations of these materials did not induce ROS formation within 2-h exposure but produced LPO and ΔΨm alteration in a concentration-dependent manner when cells were exposed for 24 h. Overall, the results found in this study support the hypothesis that carvacrol- and thymol-functionalised MCM-41 microparticles induced toxicity in HepG2 cells by an oxidative stress-related mechanism that resulted in apoptosis through the mitochondrial pathway.



Government of Spain