Isatin-modified Calixarene derivatives: A comprehensive study on synthesis, enzyme inhibition, antioxidant, antimicrobial, and Antiproliferative activities.

In this article, a series of calix[4]arenes derivatized with isatin derivatives at the phenolic-O position were synthesized as potential theranostic molecules for antitumor therapy. The cytotoxic mechanism of action of the synthesized compounds was determined by Alamar Blue assay and flow cytometry using MCF-7, MDA-MB-231, DLD1, HeLa and A549 human cancer cell lines and their ability to penetrate into PNT1A healthy epithelial cells. To detect DNA damage, the Comet test was applied after the synthesized compounds interacted with the cells. As a result, it was found that treated cells had abnormal tail nuclei and damaged DNA structures compared with untreated cells. Within the scope of enzyme inhibition experiments, studies were carried out on aromatase and COX-2 enzymes and it was determined that the compounds in the series showed inhibitory activity at varying rates. Especially compounds CLX-A3, CLX-A4, CLX-B3 and CLX-B5 attract attention with their enzyme inhibitor potential. Also, the antioxidant activities of the compounds whose synthesis was completed were also investigated and it was observed that the examined derivatives also had antioxidant activity potential. As a result of the antibacterial and antifungal test performed with broth microdilution, it was observed that the compounds had significant antibacterial and antifungal activity. The lowest MIC values were recorded as 0.006 mg/ml against Sarcina lutea and 0.048 against Candida albicans. In addition, the compound CLX-B3was observed to be effective against all strains including, Klebsiella pneumoniae and Salmonella enteritidis (Gram-negative pathogenic bacteria).