Synthesis, Antioxidant, Cytotoxicity, Induce Apoptosis Investigation and Docking Study of New Halogenated...

Chromene derivatives showed numerous biological activities. In the current study, the antioxidant, cytotoxicity, and apoptosis properties of halogenated dihydropyrano[3,2-b]chromene-3-carbonitrile derivatives (HDCCD) on MCF-7 cell line have been examined.

This study's principal point was synthesizing new halogenated pyranochromene derivatives and assessing their cytotoxic effects and apoptosis potential on MCF-7 breast cancer cell line by flow cytometry.

Initially, 6-chloro- and 6-bromo-3-hydroxychromone compounds were prepared. In the next step, a series of HDCCD were synthesized by a one-pot three-component reaction of these two compounds, aromatic aldehydes, and malononitrile, in the presence of triethylamine in EtOH at reflux conditions. These compounds were fully characterized by standard spectroscopic techniques (IR, ¹H, and ¹³C NMR) and elemental analyses. The potential of the antioxidant activity was determined by using ferric reducing antioxidant power assay (FRAP). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and lactate dehydrogenase (LDH) were used to evaluate metabolic activity. The nitric oxide (NO) and malondialdehyde (MDA) biomarkers of the exposed cells were evaluated on the cells and their supernatant. To quantify apoptotic death of MCF-7 breast cancer cells treated by the compounds at their IC₅₀ concentrations, Annexin V-FITC apoptosis detection kit was utilized. Molecular docking of compounds (6a-j) into the Cyclin-dependent kinase 6 (PDB code: 4EZ5) was carried out, and the probable binding mode of compounds 6e and 6j was determined.

A dose-response relationship was seen in all the compounds. Most of them induced cytotoxic effects on the cells. Nitrite concentration of the culture media of the cells was decreased compared to the control. Malondialdehyde levels of the cells were below the range of the control by the addition of 6b, 6d, 6e, 6f, and 6g compounds on the cells, while the addition of the 6a, 6c, 6h, 6i, and 6j compounds increased the MDA level compared to the control. Flow cytometric analysis showed that most of the exposed cells were in the early and late apoptotic stage, and a few of them were in the necrotic stage.

It could be concluded that HDCCD (6a-j) was toxic and caused death in the cells by apoptosis. The compounds have lipophilic characteristics, so they can easily pass the cell membrane. As confirmed by LDH results, it can be concluded that the cytotoxicity is connected with apoptosis rather than necrosis, endorsed by flowcytometry analysis afterward.