Efeito do extrato de alcaçuz (glycyrrhiza glabra) associado à fototerapia sobre a viabilidade de células de câncer oral

Abstract

This study evaluated the viability of using a commercial Glycyrrhiza glabra (G. glabra) extract as an antineoplastic agent and as a photosensitizer (FS) for photodynamic therapy (PDT). The quality of the extract was measured by high-performance liquid chromatography (HPLC) coupled with mass spectrometry (MS), and quantitation of phenolic compounds was accomplished by reducing the Folin-Ciocalteu reagent. Keratinocytes derived from human mouth carcinoma (SCC9 lineage) and normal mouth keratinocytes (HaCaT lineage) were treated with different concentrations of the extract. The plates were incubated for 48 hours, and cell viability was evaluated by the MTT method. The viability of using the extract as FS was assessed by absorption spectroscopy and production capacity of reactive oxygen species (ROS). The HPLC-MS analysis allowed the identification of four chemical compounds that are considered markers of the G. glabra species. The extract was able to inhibit the viability of the lineage SCC9 in a dose-dependent manner starting at a concentration of 5x10-4 µg/µL (10% reduction), reducing the viability of the cultures by 80% at a concentration of 5x10-3 µg/µL. In HaCaT lineage, the extract began to show a cytotoxic effect at concentrations of 5x10-4 µg/µL. Using the extract as an FS at a concentration of 1,21x10-2µg/µL, there was no formation of ROS, but when photoactivated at 470 nm at a concentration of 1,21x10-2µg/µL, there was a photochemical effect. While the extract can generate ROS when photoactivated, toxic concentration takes longer to develop for normal cells than for tumor cells. In the assessed presentation, G. glabra extract showed a toxic effect on SCC9 tumor cells and an ability to generate ROS by photoactivation. But there is a need for further studies to identify the compounds responsible for toxicity and for enhancement of photochemical action.