Scientists from Banaras Hindu University in Varanasi, India recently studied how acarbose (ACA) and quercetin (QUE) can inhibit digestive enzymes like α-amylase, and how this process can help prevent conditions like type 2 diabetes. Their findings were published in Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy (1).
Type 2 diabetes is a condition where cells in one’s body develop insulin resistance. As the pancreas creates more insulin to get responses from cells, eventually it will be unable to keep up, causing a rise in blood sugar and setting the stage for Type 2 diabetes. This condition can develop symptoms over several years and go unnoticed for a long time. If left unchecked, high blood sugar can be very damaging and cause serious health problems, such as heart disease, vision loss, and kidney disease.
Approximately 38 million Americans (approximately 1 in 10) have diabetes, with 90–95% of them having Type 2 diabetes (2). Studies have showed that factors like high postprandial plasma glucose concentration may raise the risk of type 2 diabetes and metabolic syndromes. One strategy for handling this can be controlling postprandial blood glucose levels, with the inhibition of the α-amylase digestive enzyme leading to successful reductions of postprandial blood glucose increases.
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Acarbose (ACA) and quercetin (QUE), are compounds present in teas and medicinal plants, and their bioactivities have drawn interest, as they can reduce the risk of developing several illnesses, including type 2 diabetes. This effect likely stems from their antioxidative capabilities, their effect on enzymes, and their impact on signal transduction pathways. Research has shown that flavonoids can reduce α-amylase activity, which can subsequently lead to anti-hyperglycemic and protective impacts that fight against the onset of diabetes. ACA and QUE interact with enzymes and significantly alter proteins’ physico-chemical characteristics and structural makeups, which affects their catalytic activity. In this study, the scientists used various spectroscopic techniques, including fluorescence, circular dichroism (CD), and docking, to measure how ACA and QUE affect the functional abilities of α-amylase. Fluorescence spectroscopy analyzes fluorescence from a molecule based on its fluorescence properties (3). As for CD, it is an absorption spectroscopy method based on differential absorption of left and right circularly polarized light (4).
Following these procedures, it was found that both drugs suppressed α-amylase activity, with greater inhibition being reported at higher concentrations. When tryptophan residues were used as an intrinsic fluorescence probe, the scientists were able to observe conformational changes in α-amylase, with CD measurements being used to explore the secondary structure in the presence of QUE and ACA. Docking studies showed effective interactions between α-amylase, QUE, and ACA, with higher binding energies as a byproduct. Finally, the stability and volatility of these complexes was established using a trajectory analysis. The scientists hope to use these findings as benchmarks for the development of new α-amylase-related therapeutics.
(1) Kumar, A.; Singh, V. K.; Kayastha, A. M. Studies on α-Amylase Inhibition by Acarbose and Quercetin Using Fluorescence, Circular Dichroism, Docking, and Dynamics Simulations. Spectrochim. Acta Part A: Mol. Biomol. Spectrosc. 2024, 314, 124160. DOI:
(2) Type 2 Diabetes. U.S. Department of Health & Human Services 2024.
(3) What is Fluorescence Spectroscopy? Horiba Scientific 2024.
(4) Circular Dichroism. LibreTexts Chemistry 2024.
