Abstract:
Objectives This study was done to synthesize a novel Zn(II)-gallic acid complex
with improved antidiabetic and antioxidative properties.
Methods The complex was synthesized and characterized using Fourier Transform
Infrared (FT-IR) and 1H NMR. Cytotoxicity was evaluated using Chang
liver cells and L6 myotubes. Radical scavenging and Fe3+-reducing, as well as α-
glucosidase, α-amylase and glycation inhibitory properties were measured. Glucose
uptake was measured in L6 myotubes, while the complex was docked against
glucose transporter type 4 (GLUT-4) and protein kinase B (PKB).
Key findings Analysis showed that complexation occurred through a Zn(O4)
coordination; thus, the complex acquired two moieties of gallic acid, which suggests
why complexation increased the DPPH (IC50 = 48.2 μM) and ABTS (IC50 =
12.7 μM) scavenging and α-glucosidase inhibitory (IC50 = 58.5 μM) properties of
gallic acid by several folds (5.5, 3.6 and 2.7 folds; IC50 = 8.79, 3.51 and 21.5 μM,
respectively). Zn(II) conferred a potent dose-dependent glucose uptake activity
(EC50 = 9.17 μM) on gallic acid, without reducing the viability of L6 myotubes
and hepatocytes. Docking analysis showed the complex had stronger interaction
with insulin signalling proteins (GLUT-4 and PKB) than its precursor.
Conclusions Data suggest that complexation of Zn(II) with gallic acid resulted
in a complex with improved and multi-facet antioxidative and glycaemic control
properties.
