Non-cytotoxic 3-Acetylcoumarin as an Attractive Target for Human Monoamine Oxidase (HMAO) Enzymes.

BACKGROUND/AIM: Coumarins are a broad class of naturally occurring oxygen-heterocyclic compounds found in plants with diverse biological properties, making them attractive for evaluation as novel therapeutic agents. We herein report the in vitro cytotoxic and monoamine oxidase (MAO) inhibitory activities of 3-acetylcoumarins (6a-e). MATERIALS AND METHODS: The cytotoxic activity was evaluated using crystal violet dye binding assay, and those compounds unable to induce cytotoxicity were further tested for the monoamine oxidase (MAO) activity using the MAO-GloTM kit. RESULTS: The 3-acetylcoumarins (6a-e) were non-cytotoxic (inactive) against MDA MB-231 (estrogen receptor-negative, ER-, highly invasive) and MCF-7 (estrogen receptor-positive, ER+, weakly invasive) breast cancer cell lines, but showed interesting MAOs inhibition activities. Among the synthesized compounds, 3-acetylcoumarin bearing dichloro (-diCl) (6d; IC50=0.31±0.04 µM) at Carbon-7, 8 positions showed higher inhibition, MAO B/A non-selectivity (selectivity index, SI=3.10), reversible inhibition against the hMAO-B enzyme, and neuroprotection against H2O2-treated human neuroblastoma (N2a) cells. CONCLUSION: Compound (6d) can be considered a promising scaffold for further investigation in developing hMAO-B inhibitors (MAOIs).

7,8-Diacetoxy-3-(4-methylsulfonylphenyl)-4-phenylcoumarin Induces ROS-dependent Cell Death in the A549 Human Lung Cancer Cell Line.

BACKGROUND/AIM: Coumarins comprise of a very large class of naturally occurring compounds with growing interest in their synthesis and possible applications in the treatment of various diseases. We herein report the in-vitro cytotoxic activity of 3,4-Diarylcoumarins (4a-i) in A549 (lung) and PC-3 (prostate) cancer cell lines. MATERIALS AND METHODS: The cytotoxic activity was evaluated using crystal violet dye-binding. The most active compound effect on the cell-cycle phases, mitochondrial membrane potential (MMP), reactive oxygen species (ROS) production and apoptosis were also evaluated. RESULTS: Among the synthesized compounds that were evaluated, 7,8-Diacetoxy-3-(4-(methylsulfonyl)phenyl)-4-phenylcoumrin (4f) showed highest cytotoxicity (CC50=13.5%±0.15µM) in A549 cancer cell line. The mechanism of its cytotoxic action indicated significant cell arrest in G1/G0, S and G2 phases of the cell cycle, loss of mitochondrial membrane potential (MMP), increase in reactive oxygen species (ROS) production and induction of apoptotic cell death. The cell viability result of pretreated A549 cells with antioxidant N-acetylcysteine (NAC), followed by compound 4f treatment confirmed ROS-dependent cell death. CONCLUSION: The presence of 3-4-methylsulfonyl and 7,8-diacetoxy groups on 3,4-Diarylcoumarin is critical in modulating higher cytotoxic activity and could serve as a valuable template for the development of novel synthetic compounds as potential anticancer agents for lung cancer treatment.