Isolation and Identification of Cytotoxic Compounds Present in Biomaterial Life^®

Introduction: Direct pulp capping consists of a minimally invasive procedure in which a material is placed directly over the exposed pulp to maintain dental vitality. Previous studies found that the Life^â biomaterial presented high cytotoxicity and cell death in vitro. This study aims to identify which Life^® constituents are responsible for the proliferation and viability decrease in odontoblast-like cells (MDPC-23).

Methods: The aqueous media conditioned with Life® was submitted to liquid-liquid extraction with ethyl acetate. Cells were treated with both organic and inorganic fractions, and further MTT assays were carried out to evaluate metabolic activity. The toxic compounds were determined by nuclear magnetic resonance spectroscopy (1HNMR and 13CNMR) and gas chromatography coupled with mass spectrometry (GC-MS).

Results and Discussion: The organic phase showed a significant decrease in metabolic activity. On the other hand, no cytotoxic effect was observed with the inorganic fraction. From the spectroscopic analysis, the organic extract was identified as a mixture of isomers (ortho/para/meta) of N-ethyl-toluenesulfonamide. For the first time, the phase and compound associated with Life^â induced cell death were determined. Given this biomaterial's moderate clinical success, our results support the development of new materials with improved biocompatibility characteristics.

Conclusions: The toxicity of biomaterial Life® in MDPC-23 cells was confirmed. N-ethyl-toluenesulfonamide was identified as the toxic agent. Although it is no longer considered a gold standard, this biomaterial remains widely used in clinical practice. However, based on our results, its application is not recommended.