Evaluation of silver-doped indium oxide nanoparticles as in vitro α-amylase and α-glucosidase inhibitors

Pristine and 2 % silver-doped indium oxide (In 2 O 3 ) nanoparticles, synthesized by solution combustion method, yielded spherical nanoparticles in the range of 20–30 nm. The nanoparticles were stabilized in cubic bixbyite structure as revealed from X-ray diffraction study. In order to evaluate the potential of these nanoparticles to modulate enzyme activity, α-amylase and α-glucosidase were used as model enzymes. Pristine and 2 % silver-doped In 2 O 3 nanoparticles demonstrated dose-dependent inhibition of α-amylase and α-glucosidase activities. Pristine In 2 O 3 nanoparticles demonstrated 26.4 % (300 µg/mL) and 65.3 % (300 µg/mL) inhibition against α-amylase and α-glucosidase, respectively. In contrast, silver-doped In 2 O 3 nanoparticles depicted 94.1 % (300 µg/mL) and 99.6 % (0.18 µg/mL) inhibition against α-amylase and α-glucosidase, respectively. In comparison with acarbose, a standard anti-diabetic drug that depicted absolute inhibition of α-glucosidase activity at 300 µg/mL, 2 % silver-doped In 2 O 3 nanoparticles completely inhibited α-glucosidase at a very low concentration (0.18 µg/mL). In view of our results, the activity of α-amylase and α-glucosidase, which are targets for treatment of type 2 diabetes, can be modulated using silver-doped In 2 O 3 nanoparticles in the concentration-dependent manner. Therefore, silver-doped In 2 O 3 has a potential to be used as a prospective starch blocker.