Synthesis, characterization, antidiabetic and antioxidative evaluation of a novel Zn(II)-gallic acid complex with multi-facet activity

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.

Zinc(II) mineral increased the in vitro, cellular and ex vivo antihyperglycemic and antioxidative pharmacological profile of p‐hydroxybenzoic acid upon complexation

“…Phenolic acids, due to their hydrogen‐donating capacity and ability to form stable phenoxy radicals (Motloung et al., 2020), quench prooxidant radicals that can cause oxidative damage to biological molecules and mediate complications in several diseases, including diabetes (Chukwuma & Islam, 2017). Studies have shown that position of non‐carboxylic –OH group in phenolic acids can influence their radical scavenging activity, with those having –OH group at “ortho” and/or “ para ” position (eg, p‐hydroxybenzoic acid and derivatives) showing stronger radical quenching activity (Velika & Kron, 2012).…”

“…The DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) and ABTS [2,2′‐Azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) diammonium salt] radical scavenging assay, as well as the Fe 3+ reducing assay where used as in vitro models to measure the antioxidant properties of the test samples according to the protocols reported by Motloung et al. (2020).…”

“…The inhibitory effect of the complex and other test samples on α‐amylase and α‐glucosidase activity was measured and the inhibition percentage was computed using the protocol reported by Motloung et al. (2020).…”

The beauty of biocatalysis: sustainable synthesis of ingredients in cosmetics

“…dextran). 105–107 In 2017, Yang and co-workers utilised Leuconostoc glucansucrase for the transglycosylation of gallic acid. 108 The resulting GA glycoside 23 (Fig.…”

Zinc(II) complexes in diabetes management: Plant‐derived phenolics as understudied promising ligands

“…In a previous study (Motloung et al., 2020), Zn(II) was chemically combined with gallic acid in a 1:2 mole ratio, respectively, to form a Zn(II)‐gallic acid complex. It was shown that Zn(II) complexed with gallic acid through a Zn(O 4 ) coordination mode, which afforded the resulting complex two moieties of gallic acid, and thus, improved the innate antioxidant and bioactive property of the phenolic acid ligand by several folds, while conferring its insulin mimetic potentials on the complex (Figure 1).…”