Chemical Composition, Antioxidant, and Cytotoxic Effects of Senna rugosa Leaf and Root Extracts on Human Leukemia Cell Lines

Abstract

Senna rugosa is a species found in the Cerrado and used in folk medicine as a vermifuge and in the treatment of poisonous snakebites accidents. In this work, we identified the main secondary metabolites present in ethanolic extracts of the leaves (ELSR) and roots (ERSR) of S. rugosa and evaluated the potential cytoprotective effect against cellular macromolecular damage, as well as the cytotoxic properties of the extracts on the K562 and Jurkat leukemic cell lines. The identification of metabolites was carried out by liquid chromatography coupled with mass spectrometry. The antioxidant activities were investigated by direct ABTS•+ and DPPH• radical scavenging methods, protection against oxidative damage in proteins, and DNA. Cytotoxic properties were investigated against healthy cells, isolated from human peripheral blood (PBMC) and leukemic cell lines. The leaf extracts contained catechin, rutin, epigallocatechin derivatives, kaempferol glycosides, luteolin, and dimeric and trimeric procyanidins, while the root extract profile showed obtusichromoneside derivatives, 2-methoxystypandrone, stilbene derivatives, naphthopyranones, and flavanone derivatives. The extracts showed antioxidant activity, with an IC50 of 4.86 ± 0.51 μg/mL and 8.33 ± 0.90 μg/mL in the ABTS assay for ELSR and ERSR, respectively. Furthermore, in the DPPH• assay, the IC50 was 19.98 ± 1.96 μg/mL for ELSR and 13.37 ± 1.05 μg/mL for ERSR. The extracts protected macromolecules against oxidative damage at concentrations of 5 μg/mL. The cytotoxicity test against leukemic strains was observed after 24 and 48 h of treatment. After 48 h, results against the K562 cell line demonstrate an IC50 of 242.54 ± 2.38 μg/mL and 223.00 ± 2.34 μg/mL for ELSR and ERSR, respectively. While against the Jurkat cell line, these extracts showed an IC50 of 171.45 ± 2.25 μg/mL and 189.30 ± 2.27 μg/mL, respectively. The results pertaining to PBMC viability demonstrated that the extracts showed selectivity for the leukemic cell lines. Together, our results reveal that the leaves and roots of S. rugosa have completely distinct and complex chemical compositions and expand their significant pharmacological potential in oxidative stress and leukemia conditions.