α-Glucosidase Inhibitory Activities and the Interaction Mechanism of Novel Spiro-Flavoalkaloids from YingDe Green Tea.
J Agric Food Chem
; 70(1): 136-148, 2022 Jan 12.
Article
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| MEDLINE
| ID: mdl-34964344
ABSTRACT
Flavoalkaloids are a unique class of compounds in tea, most of which have an N-ethyl-2-pyrrolidinone moiety substituted at the A ring of a catechin skeleton. 1-Ethyl-5-hydroxy-pyrrolidone, a decomposed product of theanine, was supposed to be the key intermediate to form tea flavoalkaloids. However, we have also detected another possible theanine intermediate, 1-ethyl-5-oxopyrrolidine-2-carboxylic acid, and speculated if there are related conjugated catechins. Herein, four novel spiro-flavoalkaloids with a spiro-γ-lactone structural moiety were isolated from Yingde green tea (Camellia sinensis var. assamica) in our continuing exploration of new chemical constituents from tea. The structures of the new compounds, spiro-flavoalkaloids A-D (1-4), were further elucidated by extensive nuclear magnetic resonance (NMR) spectroscopy together with the calculated 13C NMR, IR, UV-vis, high-resolution mass, optical rotation, experimental, and calculated circular dichroism spectra. We also provided an alternative pathway to produce these novel spiro-flavoalkaloids. Additionally, their α-glucosidase inhibitory activities were determined with IC50 values of 3.34 (1), 5.47 (2), 22.50 (3), and 15.38 (4) µM. Docking results revealed that compounds 1 and 2 mainly interacted with residues ASP-215, ARG-442, ASP-352, GLU-411, HIS-280, ARG-315, and ASN-415 of α-glucosidase through hydrogen bonds. The fluorescence intensity of α-glucosidase could be quenched by compounds 1 and 2 in a static style.
Palabras clave
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Té
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Camellia sinensis
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Alcaloides
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Inhibidores de Glicósido Hidrolasas
Idioma:
En
Revista:
J Agric Food Chem
Año:
2022
Tipo del documento:
Article
País de afiliación:
China