Isatin-hydrazide conjugates as potent α-amylase and α-glucosidase inhibitors: Synthesis, structure and in vitro evaluations

Managing diabetes that is a global life-threatening problem, remains a challenge for the scientific community. The inhibition of alpha-amylase and alpha-glucosidase enzymes which are responsible for the digestion of dietary carbohydrates is an effective strategy to control postprandial hyperglycemia. Herein, we report the novel and highly potent inhibitors of alpha-amylase and alpha-glucosidase, namely isatin-hydrazide conjugates 1a - 1j that are easily accessed in two steps from simple and inexpensive commercially available isatin. The in vitro bio-evaluations of these compounds revealed that conjugates 1a, 1h and 1f are highly potent inhibitors of alpha-amylase with IC50 values of 19.6, 12.1 and 18.3 mu g/ml, respectively as compared to the standard, acarbose (IC50 = 36.2 mu g/ml). Similarly, the conjugates 1a, 1b, 1d, 1f and 1i showed significant activity against alpha-glucosidase with IC50 values of 14.8, 25.6, 13.2, 14.5 and 16.5 mu g/ml, respectively as compared to the acarbose (IC50 = 34.5 mu g/ml). Notably, the compounds 1a and 1f were found to be highly potent against both alpha-amylase and alpha-glucosidase enzymes, demonstrating about two-fold better inhibitory activity than the reference inhibitor. Molecular docking studies were performed to recognize the possible binding modes of the compounds with the active pocket of the enzymes. The results of this study divulge the potential of these compounds as powerful and inexpensive lead molecules for future investigations.