Exploring the Inhibitory Potential of Six Porphyrin Compounds Against α-Amylase and α-Glucosidase Linked to Diabetes

Diabetes mellitus is a characteristic metabolic disorder with diverse complications. α-Amylase and α-glucosidase, as key digestive enzymes regulating blood glucose, are important targets for diabetes prevention and management through their inhibition. This study investigated the inhibitory effects of six porphyrin compounds (TAPP, TCPP, THPP, Cu-TCPP, Fe-TCPP, Ni-TCPP) on two enzymes through in vitro inhibition assays, spectroscopic experiments, and molecular docking techniques. All six compounds effectively inhibited the activities of both enzymes. For α-amylase, the inhibitory potency (IC₅₀ = 13.03-245.04 μg/mL) followed the order TAPP > THPP > TCPP > Fe-TCPP > Ni-TCPP > Cu-TCPP. All six compounds exhibited more potent inhibitory activity against α-glucosidase (IC₅₀ = 0.24-25.43 μg/mL), with potency in the order of THPP > Ni-TCPP > Fe-TCPP > TCPP > Cu-TCPP > TAPP. Fluorescence quenching experiments revealed that all compounds statically quenched the intrinsic fluorescence of both enzymes (with Fe-TCPP exhibiting static-dominant mixed quenching against α-amylase), indicating complex formation. These interactions significantly altered the enzymes' conformations, the microenvironments of Tyr/Trp residues, and secondary structure content, consequently reducing their catalytic activity. By examining the inhibitory impact of porphyrin compounds on α-amylase and α-glucosidase, this research establishes a vital experimental and theoretical basis for diabetes therapeutics.