Antioxidant activity and inhibitory effect of curcumin on some enzymes involved in several diseases: Acetylcholinesterase, butyrylcholinesterase, α-glucosidase and tyrosinase

This study aims the investigation of the potential effect of pure curcumin on the inhibition of different enzymes which are involved in several diseases. Several chronic diseases such as Alzheimer’s, diabetes, and Parkinson’s disease are related to oxidative stress and enzyme activity. Today, various plant origin products are stated as beneficial against several chronic diseases with secondary metabolites such as phenolic compounds. Curcumin, a polyphenol yellow-orange pigment present in turmeric spices, has a wide range of biological activities, with quite a safety. This study was aimed to investigate the antioxidant and inhibitory potential against key enzymes involved in human pathology, namely Alzheimer's disease (Acetylcholinesterase (AChE), and Butyrylcholinesterase (BChE)), diabetes (α-glucosidase) and hyperpigmentation and Parkinson’s diseases (Tyrosinase) of curcumin. 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH●) and hydrogen peroxide radicals (H2O2) assays were used to evaluate the antioxidant capacity of curcumin, enzyme inhibitory activity was evaluated using in vitro standard procedures. Curcumin exhibited an excellent antioxidant effect with an IC50 value significantly less than the reference, Vit C. In enzyme inhibitory activity, curcumin demonstrated excellent inhibitory activity against AChE, BChE and α-glucosidase. The finding showed that curcumin was significantly less than the reference galantamine against AChE, but was significantly more than the references galantamine and acarbose against BChE and α-glucosidase, respectively. Whereas for anti-tyrosinase activity, curcumin displayed weak inhibitory activity compared with the standard inhibitor, Kojic acid.