Background: Curcumin, as the substantial constituent of the turmeric plant (Curcuma longa),
plays a significant role in the prevention of various diseases, including diabetes. It possesses ideal structure
features as an enzyme inhibitor, including a flexible backbone, hydrophobic nature, and several
available hydrogen bond (H-bond) donors and acceptors.
Objective: The present study aimed at synthesizing several novel curcumin derivatives and further
evaluation of these compounds for possible antioxidant and anti-diabetic properties along with inhibitory
effect against two carbohydrate-hydrolyzing enzymes, α-amylase and α-glucosidase, as these enzymes
are therapeutic targets for attenuation of postprandial hyperglycemia.
Methods: Therefore, curcumin-based pyrido[2,3-d]pyrimidine derivatives were synthesized and identified
using an instrumental technique like NMR spectroscopy and then screened for antioxidant and enzyme
inhibitory potential. Total antioxidant activity, reducing power assay and 1,1-diphenyl-2-
picrylhydrazyl (DPPH•) radical scavenging activity were done to appraise the antioxidant potential of
these compounds in vitro.
Results: Compounds L6-L9 showed higher antioxidant activity while L4, L9, L12 and especially L8
exhibited the best selectivity index (lowest α-amylase/α-glucosidase inhibition ratio).
Conclusion: These antioxidant inhibitors may be potential anti-diabetic drugs, not only to reduce glycemic
index but also to limit the activity of the major reactive oxygen species (ROS) producing pathways.