Anticancer Enzyme Inhibition Potential of Organosulphur Compounds via Histone Deacetylase, Carbonic Anhydrase, and Xanthine Oxidase Inhibition

Objective: Histone deacetylases (HDACs) are critical epigenetic regulators of gene expression and represent important pharmacological targets in cancer therapy. Moreover, carbonic anhydrase (CA) and xanthine oxidase (XO) are key enzymes involved in cellular homeostasis, including pH regulation, ion transport, oxygen metabolism, and oxidative stress, all of which are closely associated with tumour progression and cancer-related metabolic reprogramming. Considering the pharmacological relevance of these enzymes, organosulphur compounds—known for their antioxidant, anti inflammatory, immunomodulatory, antimicrobial, and antiaging properties—were evaluated for their anticancer-related enzyme inhibitory activity against HDAC, CA, and XO.Materials and Methods: Fluorometric and spectrophotometric assays were used to evaluate the anti-HDAC, anti-CA, and anti-XO activities of the sulphur compounds.Results: L-cysteine hydrochloride (IC50=17. 66 mg/mL) and L-alliin (IC50=0.0000419 mg/mL) had the lowest IC50 value for HDAC and XO inhibitor activities among the sulphur compounds, respectively. D,L-methionine (IC50=18.76 mg/mL) and N-acetyl-L-cysteine (IC50=29.02 mg/mL) inhibited HDAC activity more than the other tested compounds. All tested organosulphur compounds, such as N-acetyl-L-cysteine, L-cysteine hydrochloride, S-allyl-L-cysteine, S-phenyl-L-cysteine, and S-benzyl-L-cysteine, exhibited CA inhibitory activities.Conclusion: These organosulphur compounds exhibited in vitro inhibitory activity against cancer-related target enzymes and may serve as promising lead compounds for further anticancer research.