Flavones from Combretum quadrangulare Growing in Vietnam and Their Alpha-Glucosidase Inhibitory Activity

• Published in: Molecules (Basel, Switzerland) Vol. 26; no. 9; p. 2531
• Main Authors: Dao, Thi-Bich-Ngoc, Nguyen, Truong-Minh-Tri, Nguyen, Van-Quy, Tran, Thi-Minh-Dinh, Tran, Nguyen-Minh-An, Nguyen, Chuong Hoang, Nguyen, Thi-Hoai-Thu, Nguyen, Huu-Hung, Sichaem, Jirapast, Tran, Cong-Luan, Duong, Thuc-Huy
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 26-04-2021; MDPI
• Subjects: alpha-glucosidase; Amino acids; Anthelmintic agents; antibacterial; Antibacterial activity; Antibacterial materials; Antiparasitic agents; Biological activity; Bromination; Combretum; Combretum - chemistry; Combretum quadrangulare Kurz; Cytotoxicity; Dose-Response Relationship, Drug; Drug resistance; E coli; Enzymes; Flavones; Flavones - chemistry; Flavones - isolation & purification; Flavones - pharmacology; flavonoid; Flavonoids; Glucosidase; Glycoside Hydrolase Inhibitors - chemistry; Glycoside Hydrolase Inhibitors - isolation & purification; Glycoside Hydrolase Inhibitors - pharmacology; Herbal medicine; Hydrogen Bonding; Hydrogen bonds; Ligands; Medicinal plants; Methicillin; Models, Molecular; Molecular Conformation; Molecular docking; Molecular Docking Simulation; Molecular Dynamics Simulation; Molecular Structure; Phytochemicals; Phytochemicals - chemistry; Plant Extracts - chemistry; Plant Extracts - isolation & purification; Plant Extracts - pharmacology; Seeds; Staphylococcus infections; Structure-Activity Relationship; Triterpenes; α-Glucosidase; β Lactamase; Vietnam; Combretum quadrangulare Kurz; alpha-glucosidase; antibacterial; molecular docking; flavonoid
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules26092531

Kurz is widely used in folk medicine in Eastern Asia and is associated with various ethnopharmacological properties including hepatoprotective, antipyretic, analgesic, antidysenteric, and anthelmintic activities. Previous phytochemical investigations reported the presence of numerous triterpenes (mostly cycloartanes, ursanes, lupanes, and oleananes) along with dozens of flavonoids. However, the extracts of
and isolated flavonoids have not been evaluated for their alpha-glucosidase inhibition. In the frame of our efforts dedicated to the chemical investigation of Vietnamese medicinal plants and their biological activities, a phytochemical study of the MeOH extract of the leaves of
using bioactive guided isolation was undertaken. In this paper, the isolation and structure elucidation of twelve known compounds, 5-hydroxy-3,7,4'-trimethoxyflavone (
), ayanin (
), kumatakenin (
), rhamnocitrin (
), ombuin (
), myricetin-3,7,3',5'-tetramethyl ether (
), gardenin D (
), luteolin (
), apigenin (
), mearnsetin (
), isoorientin (
), and vitexin (
) were reported. Bromination was applied to compounds
and
to provide four new synthetic analogues
-
. All isolated and synthesized compounds were evaluated for alpha-glucosidase inhibition and antibacterial activity. Compounds
and
showed moderate antibacterial activity against methicillin-resistant
while others were inactive. All compounds failed to reveal any activity toward extended spectrum beta-lactamase-producing
. Compounds
,
,
-
, and
-
showed good alpha-glucosidase inhibition with IC
values in the range of 30.5-282.0 µM. The kinetic of enzyme inhibition showed that
and
were noncompetitive type inhibition against alpha-glucosidase. In silico molecular docking model indicated that compounds
and
were potential inhibitors against enzyme
-glucosidase.