Sulfonamides incorporating ketene N,S-acetal bioisosteres as potent carbonic anhydrase and acetylcholinesterase inhibitors.

In this study, 15 novel compounds in a series of sulfonamide-based ketenes (7a-o) were synthesized and characterized using Fourier-transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and mass spectrometry. All compounds were tested for their ability to inhibit the human carbonic anhydrase (hCA) isoforms I and II, and acetylcholinesterase (AChE). The halogen-appended compounds, 7g, 7o, and 7i, exhibited the highest hCA I/II and AChE inhibition, with the KI values in the low nanomolar range (KI = 9.01 ± 0.08, 7.41 ± 0.03, and 7.37 ± 0.31 nM, respectively), as compared with their corresponding parent 2-[2,2-dicyano-1-(phenylamino)vinylthio]-N-(4-sulfamoylphenyl)acetamide analogs 7a-o. Besides, derivatives 7c and 7e selectively inhibited the isoform hCA I, whereas compounds 7m and 7n selectively inhibited isoform hCA II. These findings indicated that all compounds can inhibit metabolic dysfunctions, such as edema, epilepsy, glaucoma, and Alzheimer's disease, by specifically targeting both the hCA isoforms and AChE expression. Herein, also the interactions between ligands and receptors were highlighted through in silico molecular docking studies. The molecular mechanics-generalized Born surface area method was utilized to compute the binding free energy and the energy contribution of the critical residues in the active site was estimated. All these results would help us to perfectly understand the relationship between activity and structural characteristics of derivatives and to further improve newly and highly effective analogs targeting hCA and AChE.

A Comparison of the Inhibitory Effects of Anti-Cancer Drugs on Thioredoxin Reductase and Glutathione S-Transferase in Rat Liver.

BACKGROUND: While Thioredoxin Reductase (TrxR) plays an important role in regulation of the intracellular redox balance and various signalling pathways, Glutathione S-Transferase (GSTs) enzymes belong to the detoxification family that catalyse the conjugation of glutathione with various endogenous and xenobiotic electrophiles. Since TrxR and GSTs are overexpressed in many cancer cells, they have been identified as potential targets to develop chemotherapeutic strategies. METHOD: The mitochondrial TrxR (TrxR2) enzyme and the cytosolic GST enzyme was purified from rat liver via affinity chromatography. After the purification, the in vitro inhibition effects of some anticancer drugs (cisplatin, calcium folinate, carboplatin, epirubicin hydrochloride, doxorubicin hydrochloride, paclitaxel, etoposide, fluorouracil, and methotrexate) were investigated on both enzymes. Since only methotrexate inhibits both enzymes among all the anticancer drugs, a molecular docking study was performed to determine the binding site and the binding affinity of methotrexate to the enzymes. RESULTS: Firstly, TrxR2 and GST were found to have a specific activity of 0.436, 1765 EU/mg proteins with a yield of 39.20%, 31.28% and 207.6, 3516.6 of purification fold, respectively. While TrxR2 was strongly inhibited by all of the anticancer drugs, GST was not inhibited by any of the anticancer drugs except methotrexate. CONCLUSION: Both enzymes were inhibited by only methotrexate in rat liver, and methotrexate was well placed in the active sites of both proteins. Therefore, it may be argued that methotrexate may be a more effective anticancer drug than all other drugs used in this study against the multi drug resistance that will occur during chemotherapy.