Estudos químico-farmacêuticos, atividade antitumoral e mutagênica de Eleutherine plicata. Herb.

Abstract

Naphthoquinones have been linked to antitumor activity; however, they can cause DNA damage and be mutagenic. Some of these as the isoeleutherine and eleutherine, present in Eleutherine plicata Herb., do not have studies of mutagenicity and antitumor activity. This study evaluated the antitumor potential of the ethanolic extracts of E. plicata (EEEP), the fraction in which the quinones were found (Fraction dichloromethane-FDEP) and the genotoxic potential related to these substances. For understanding whether fractionation influences antitumor activity, EEEP was obtained by macerating the bulbs, it was fractionated under reflux and FDEP was obtained and fractionated in an open chromatographic column, resulting in the isolatation of eleutherine, isoeleutherine and eleutherol. Chemical-pharmaceutical studies were carried out: silica toxicity and pharmacokinetics (PreADMET), docking and dynamics. The antitumor activity was evaluated through the cytotoxicity in tumor cell line (oral cancer-SCC-9) and normal cell line (human keratinocytes-HaCaT), three-dimensional assay in spheroid model and cell migration in the same lines. Genotoxicity and mutagenicity were evaluated in Allium cepa model, the results of the isolated compounds were similar to those obtained in silico studies. In addition to the isoeleutherine and eleutherine, eleuterol was isolated from FDEP, the silica evaluation demonstrated similar pharmacokinetic profiles between these compounds. In the evaluation of anti-tumor activities, the EEEP fractionation contributed negatively to the activity, with EEEP (SCC09: IC50 = 12.87 ± 0.86 and HaCaT: 28.81 ± 1.82µg/mL) being the most promising with higher selectivity index for the tumor cell, interfering in the speed and directionality of tumor migration. Trying to understand this result, the capacity of naphthoquinones bind to Topoisomerase II (TOPII) was evaluated, confirming that they bind in its pouch, stabilizing the DNA-TOP II complex. In contrast, eleutherine proved to be more genotoxic, increasing the rate of mitosis, of aberrations, with micronucleus, bud and bridge being observed in the metaphase phase. However, it was not possible to differentiate the toxicity of eleutherine and isoleutherine in silico studies (Algae, Daphinia, fish and mutagenicity), obtaining similar results. In summary, EEEP is promising as a cytotoxic agent in tumor cells, and in the prevention of squamous cancer of the mouth. In relation to naphthoquinones, isoleutherine, due to its lower toxic potential and stabilization capacity of the DNA-TOP II complex, needs to be evaluated in other tumor strains.