Antibacterial and Cytotoxic Activity of Compounds Isolated fromFlourensia oolepis

Abstract

The antibacterial and cytotoxic effects of metabolites isolated from an antibacterial extract ofFlourensia oolepiswere evaluated. Bioguided fractionation led to five flavonoids, identified as 2′,4′-dihydroxychalcone (1), isoliquiritigenin (2), pinocembrin (3), 7-hydroxyflavanone (4), and 7,4′-dihydroxy-3′-methoxyflavanone (5). Compound1showed the highest antibacterial effect, with minimum inhibitory concentration (MIC) values ranging from 31 to 62 and 62 to 250 μg/mL, against Gram-positive and Gram-negative bacteria, respectively. On further assays, the cytotoxic effect of compounds1–5was determined by MTT assay on acute lymphoblastic leukemia (ALL) and chronic myeloid leukemia (CML) cell lines including their multidrug resistant (MDR) phenotypes. Compound1induced a remarkable cytotoxic activity toward ALL cells (IC50= 6.6–9.9 μM) and a lower effect against CML cells (IC50= 27.5–30.0 μM). Flow cytometry was used to analyze cell cycle distribution and cell death by PI-labeled cells and by Annexin V/PI staining, respectively. Upon treatment,1induced cell cycle arrest in the G2/M phase accompanied by a strong induction of apoptosis. These results describe for the first time the antibacterial metabolites ofF. oolepisextract, with1being the most effective. This chalcone also emerges as a selective cytotoxic agent against sensitive and resistant leukemic cells, highlighting its potential as a lead compound.