Composição química e atividades biológicas das folhas e raízes de Senna rugosa

Abstract

Senna rugosa is a shrub plant found in the Cerrado, popularly known as peanuts and used in folk medicine as a dewormer and for the treatment of snakebites. Few studies report the biological activities of S. rugosa. Thus, this study aimed to determine the chemical composition, evaluate the antioxidant activity, the protection of macromolecules and the anti-leukemic and anti-melanoma action of the ethanolic extracts of the leaves (EFSR) and roots (ERSR) of S. rugosa. The chemical composition was determined by liquid chromatography coupled with mass spectrometry. As antioxidant properties were evaluated using the ABTS•+ and DPPH• free radical capture tests, protection against oxidative damage was evaluated in proteins against oxidation induced by 2,2'-Azobis (2- amidinopropane) (AAPH) and about a DNA fragmentation induced by hydrogen (H2O2) and ultraviolet radiation (UV).Cytotoxic activity was evaluated against leukemic cell lines K562 and Jurkat, of human melanoma Sk-Mel-19, Sk-Mel-28, Sk-Mel-103, murine melanoma B16F10-Nex2, non-cancerous human lung fibroblast strains MRC-5 and human peripheral blood mononuclear cells (PBMC). The results demonstrated the presence of catechin, rutin, epigallocatechin derivatives, kaempferol glycosides, luteolin and dimeric and trimeric procyanidins in the EFSR. The extracts have IC50 for the ABTS•+ assay, with 4.86 + 0.51 μg/mL for EFSR and 8.33 + 0.90 μg/mL for ERSR, respectively, while for the DPPH• assay the IC50 values for EFSR and ERSR were 19.98 + 1.96 μg/mL and 13.37 + 1.05 μg/mL, respectively. The extracts were able to protect protein albumin against oxidation induced by AAPH and inhibit the fragmentation of plasmid DNA induced by H2O2 and UV radiation from the lowest concentration, 5 μg/mL. In addition, the extracts induced cell death of the K562 leukemic strains (IC50 of 242.54 + 2.38 μg/mL for EFSR and 223.00 + 2.34 μg/mL for ERSR), Jurkat (IC50 of 171.45 + 2.25 μg/mL for EFSR and 189.30 + 2.27 μg/mL for ERSR) and Sk-Mel-103 melanoma (IC50 of 224.66 + 2.35 μg/mL for EFSR and 221.98 + 2.34 μg/mL for ERSR), after 48 h of treatment. For the non-cancerous strain MRC-5 the extracts showed cytoxicity from the concentration of 300 μg/mL. While, for PBMC cells, EFSR and ERSR showed low cytoxicity, observed only at the concentration of 500 μg/mL. Together, these results demonstrate that the extracts of S. rugosa have antioxidant activity and anti-leukemic and anti-melanoma action, being potential therapeutic agents in the prevention of conditions related to oxidative stress and cancer.