In vitro inhibition of pancreatic α-amylase by spherical and polygonal starch nanoparticles

Nanoparticles are novel and fascinating materials for tuning the activities of enzymes. In this study, we investigated the influence of spherical and polygonal starch nanoparticles (SNPs) on alpha-amylase activity and revealed the reaction mechanisms by ultraviolet-visible spectrophotometry, fluorescence spectroscopy, and circular dichroism (CD) spectroscopy. We discovered that both spherical and polygonal SNPs could inhibit the a-amylase activity, with half-inhibitory concentration values of 0.304 and 0.019 mg mL(-1), respectively. Furthermore, spherical and polygonal SNPs followed competitive and mixed competitive inhibition mechanisms, respectively. The fluorescence data indicated that static quenching was dominant in the interaction between SNPs and a-amylase. The CD results demonstrated that the inhibition of alpha-amylase by SNPs was accompanied by the decreased intensity of the CD spectra of alpha-amylase. Our findings provide a novel strategy to inhibit a-amylase to reduce the digestion of starch, thus managing blood glucose levels.