Dynamic Responses of α-Amylase to Diets and Their Impact on Metabolic Health: Insights from a Novel Noninvasive Imaging.

α-Amylase plays a central role in carbohydrate digestion and is an important target for the management of metabolic disorders, yet its dynamic activity in vivo remains poorly understood. Here, we developed a near-infrared supramolecular probe, M@γ-CD, for rapid, noninvasive, and sensitive detection of α-amylase activity. The probe was formed through host-guest complexation between γ-cyclodextrin (γ-CD) and a donor-π-acceptor fluorophore. M@γ-CD reliably detected α-amylase under physiological conditions and at low concentrations in vitro. Using M@γ-CD, we found that intestinal α-amylase activity in mice peaked 2 h after feeding and was elevated by high-fat and high-starch diets. Green tea administration reduced intestinal α-amylase activity, improved glucose and lipid metabolism, and alleviated obesity, suggesting that modulation of α-amylase activity may contribute to its antiobesity effects. These findings demonstrate the in vivo applicability of M@γ-CD and highlight its potential for monitoring digestive enzyme dynamics and guiding metabolic interventions targeting α-amylase.