Produção e avaliação da atividade citotóxica/antitumoral de extrato de Alternanthera brasiliana (L.) kuntze

Abstract

The search for effective and economically accessible therapeutic alternatives has motivated research involving medicinal plants with bioactive potential. Alternanthera brasiliana (L.) Kuntze, popularly known as penicilina or terramicina, has previously explored pharmacological properties, such as anti-inflammatory, antimicrobial, hepatoprotective, and analgesic actions. However, there is still a lack of studies evaluating its cytotoxic and antitumor potential, especially in in vitro assays. Therefore, this work aimed to produce an extract of A. brasiliana and evaluate its cytotoxic activity in normal cells (NIH3T3) and antitumor activity in human hepatoma cells (HepG2). Leaves were collected, dried, ground, and subjected to granulometric separation, with the fraction retained at 0.3 mm (87.54% of total mass) used for extraction. The process was optimized using a Central Composite Rotational Design (CCRD) 2³, evaluating three independent variables: temperature, extraction time, and plant concentration. Quantification of phenolic compounds was performed by the Folin-Ciocalteu method. Statistical analysis (ANOVA) indicated significance of the linear and quadratic terms, allowing the fitting of a mathematical model (R² = 0.793) for predicting phenolic content. Through response surface methodology analysis, the best extraction conditions were found at approximately 86.8 °C, 46.5 minutes, and 0.015 g mL⁻¹, resulting in an estimated content of 274.5 mg GAE g⁻¹ of extract. FTIR analysis suggests the presence of characteristic functional groups of aromatic compounds, phenols, and flavonoids in both the plant and the extract. Cytotoxicity assessment, performed by the MTT assay, revealed that the dry extract exhibited greater antitumor selectivity, significantly reducing the viability of HepG2 cells from 10 mg mL⁻¹, while NIH3T3 cells were affected only at doses above 300 mg mL⁻¹. In contrast, the liquid extract showed early cytotoxicity in NIH3T3 cells, with lower selectivity. These results suggest that the drying process may concentrate the bioactive compounds, possibly increasing their efficacy and selectivity against tumor cells. Thus, A. brasiliana shows promising potential in producing extracts with antitumor activity, especially in its dry form, highlighting its pharmacological value and encouraging future studies to deepen the characterization of the compounds involved and their mechanisms of action.