INVESTIGAÇÃO DA COMPOSIÇÃO QUÍMICA E AVALIAÇÃO DAS PROPRIEDADES BIOLÓGICAS DE Aspidosperma nobile Müll. Arg. (APOCYNACEAE)

Abstract

The objective of the current work was to conduct a chemical and biological study aimed at isolating, characterizing, and evaluating the biological activities of the extract from the leaves and latex of Aspidosperma nobile Müll. Arg. (Apocynacea). The plant material (leaves and latex obtained from stems) was collected from the permanent preservation unit at UFMS in Campo Grande, MS. The leaves were crushed and subjected to exhaustive extraction with ethanol, while the latex was dried and subsequently extracted with methanol and methanol/water. The ethanolic extract of the leaves were submitted to liquid-liquid partition, resulting in the hexane, dichloromethane, ethyl acetate, and hydromethanolic phases. Among the resulting phases, the hexane phase was chosen for column chromatography procedures due to its yield, and the dichloromethane phase due to its moderate antimicrobial activity. The antimicrobial activity assay was conducted using the broth microdilution method, and the antiproliferative activity was evaluated through the sulforhodamine B (SRB) colorimetric assay. Structural determination was carried out based on the analysis and listing of 1H and 13C nuclear magnetic resonance uni- and bidimensional data, along with comparison with literature data. Through the combination of chromatographic techniques, 10 substances were isolated: 1 acyclic triterpene (squalene); 4 lupane-type triterpenes (lupeol, lupeol esterified with fatty acid, betulin, and betulinic acid); 2 steroids (stigmasterol and β-sitosterol); 1 polyol (L-quebrachitol); 1 ursane-type triterpene (ursolic acid); and a phenylpropanoid not previously reported in the literature. In the evaluation of antimicrobial activity against standard strains of Staphylococcus aureus and Escherichia coli, the leaf extract and phases were inactive (MIC ≥ 1000 µg/mL), except for the dichloromethane phase, which exhibited moderate activity against S. aureus (MIC of 500 µg/mL). Regarding antiproliferative activity, the leaf extract presented growth inhibitory activity (GI50) of 0.23 µg/mL against the human glioblastoma cell line (U251), 3.57 µg/mL against renal adenocarcinoma (786), and 34.25 µg/mL against murine melanoma (B16F10). For the latex extract, GI50 values of 0.05 µg/mL (5 times more active than the positive control) were observed against the U251 cell line, with a selectivity of 52.8 times for the tumor cell line, GI50 of 3.30 µg/mL against 786, and 260.61 µg/mL against B16F10. Thus, this work represents the first investigation into the chemical composition and potential biological activities of A. nobile, revealing promising antiproliferative activities for the leaf and latex extracts of this species.