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Screening of α‐Glucosidase Inhibitors from Houttuynia cordata and Evaluation of the Binding Mechanisms
Author(s) -
Zhang Xueli,
Cheng Bingjie,
Liu Xixia,
Li Yani,
Hou Jianjun,
Chen Sirui,
Chen Jiamin,
Li Shuyue
Publication year - 2020
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.202001657
Subject(s) - quercitrin , chemistry , acarbose , stereochemistry , biochemistry , flavonoid , enzyme , antioxidant
α‐glucosidase inhibitors have been used to treat diabetes for many years. Recently, natural products have attracted much attention, because they are kinds of safety source to screen α‐glucosidase inhibitor. In this study, we separated two monomers (quercitrin and afzelin) from Houttuynia cordata with notable inhibitory activity against α‐glucosidase, and evaluated inhibitory kinetics and the binding mechanisms. The 50% inhibitory concentration (IC 50 ) of the quercitrin and afzelin were 0.231±0.033 mg/mL and 0.215±0.004 mg/mL, which were lower than the IC 50 of acarbose. The inhibitory type between α‐glucosidase and the two monomers was a competitive inhibition, which is similar to acarbose and could compete binding sites. The fluorescence spectroscopy showed that quercitrin and afzelin statically quenched the fluorescence of α‐glucosidase. Circular dichroism and molecular docking analyses indicated that quercitrin and afzelin changed the alpha‐helix structure of α‐glucosidase and bound with the key amino acids through hydrophobic interactions, hydrogen bonds and salt bridge interaction. This study is the first time to clarify the inhibitory kinetics and binding mechanisms of quercitrin and afzelin on α‐glucosidase.