Anotação química e potencial antiproliferativo dos extratos metanólicos e frações das folhas e flores de Parkia platycephala (Fabaceae)

Abstract

Maranhão state hosts one of the richest and most diverse biodiversities in Brazil, a result of its unique geographical position where the Amazon, Cerrado, and Caatinga biomes converge. This ecological confluence favors the occurrence of plant species that remain under-explored regarding their chemical and biological potential. In this context, the present study investigated the chemical profile and antiproliferative potential of extracts and fractions from the leaves and flowers of Parkia platycephala, an endemic Cerrado species belonging to the Fabaceae family. The methanolic extracts of leaves (EBFL) and flowers (EBFR) underwent liquid-liquid partitioning, yielding hexanic (FHFL; FHFR) and ethyl acetate (FAFL; FAFR) fractions. Analysis by Liquid Chromatography coupled with Electrospray Ionization Ion Trap Mass Spectrometry (LC-ESI-IT/MS) allowed the annotation of phenolic compounds. Molecules from the classes of shikimic acid derivatives, flavonoids, proanthocyanidins, and lignans were putatively annotated, the latter potentially not yet reported in the Parkia genus. Cytotoxic activity was evaluated using the MTT assay (3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide) against five human tumor cell lines (A549, PC–3, HT–29, BxPC–3, and MCF–7) and one non-tumor cell line (HPrEpiC) to determine the Half-Maximal Inhibitory Concentration (IC50) and Selectivity Index (SI). The results revealed that the crude extracts were inactive at the tested concentrations, while the FHFL and FAFL fractions exhibited IC50 values between 8.4 and 50 μg/mL. Notable results included the antiproliferative activity (IC50 = 8.4 μg/mL) and high selectivity (SI = 11.90) of FHFL against the MCF–7 cell line. Flower fractions (FHFR and FAFR) demonstrated activity against BxPC–3, albeit with high toxicity toward non-tumor cells (SI < 1). The data indicate that fractionation concentrated the bioactive compounds and that P. platycephala leaves constitute a promising source of selective biomolecules, reinforcing the biopharmacological potential of the species for the development of new antitumoral agents.