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

Abstract

Pristine and 2 percent 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, alpha-amylase and alpha-glucosidase were used as model enzymes. Pristine and 2 percent silver-doped In(2)O(3) nanoparticles demonstrated dose-dependent inhibition of alpha-amylase and alpha-glucosidase activities. Pristine In(2)O(3) nanoparticles demonstrated 26.4 percent (300 mu g/mL) and 65.3 percent (300 mu g/mL) inhibition against alpha-amylase and alpha-glucosidase, respectively. In contrast, silver-doped In(2)O(3) nanoparticles depicted 94.1 percent (300 mu g/mL) and 99.6 percent (0.18 mu g/mL) inhibition against alpha-amylase and alpha-glucosidase, respectively. In comparison with acarbose, a standard anti-diabetic drug that depicted absolute inhibition of alpha-glucosidase activity at 300 mu g/mL, 2 percent silver-doped In(2)O(3) nanoparticles completely inhibited alpha-glucosidase at a very low concentration (0.18 mu g/mL). In view of our results, the activity of alpha-amylase and alpha-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 In2O3 has a potential to be used as a prospective starch blocker.