Effect of silver doping on antidiabetic and antioxidant potential of ZnO nanorods.

BACKGROUND: Increasing resistance to available drugs and their associated side-effects have drawn wide attention towards designing alternative therapeutic strategies for control of hyperglycemia and oxidative stress. The roles of the sizes and shapes of the nanomaterials used in the treatment and management of Type 2 Diabetes Mellitus (T2DM) in preventing chronic hyperglycaemia and oxidative stress are investigated. We report specifically on the effects of doping silver (Ag) into the ZnO nanorods (ZnO:Ag NR's) as a rational drug designing strategy. METHODS: Inhibition of porcine pancreatic α-amylase, murine pancreatic amylase, α-glucosidase, murine intestinal glucosidase and amyloglucosidase are checked for evaluation of antidiabetic potential. In addition, the radical scavenging activities of ZnO:Ag NR's against nitric oxide, DDPH and superoxide radicals are evaluated. RESULTS: Quantitative radical scavenging and metabolic enzyme inhibition activities of ZnO:Ag NR's at a concentration of 100 µg/mL were found to depend on the amount of Ag doped in up to a threshold level (3-4 %). Circular dichroism analysis revealed that the interaction of the NR's with the enzymes altered their secondary conformation. This alteration is the underlying mechanism for the potent enzyme inhibition. CONCLUSIONS: Enhanced inhibition of enzymes and scavenging of free radicals primarily responsible for reactive oxygen species (ROS) mediated damage, provide a strong scientific rationale for considering ZnO:Ag NR's as a candidate nanomedicine for controlling postprandial hyperglycaemia and the associated oxidative stress.

Gnidia glauca- and Plumbago zeylanica-Mediated Synthesis of Novel Copper Nanoparticles as Promising Antidiabetic Agents.

Rapid, eco-friendly, and cost-effective one-pot synthesis of copper nanoparticles is reported here using medicinal plants like Gnidia glauca and Plumbago zeylanica. Aqueous extracts of flower, leaf, and stem of G. glauca and leaves of P. zeylanica were prepared which could effectively reduce Cu2+ ions to CuNPs within 5 h at 100°C which were further characterized using UV-visible spectroscopy, field emission scanning electron microscopy, high-resolution transmission electron microscopy, energy dispersive spectroscopy, dynamic light scattering, X-ray diffraction, and Fourier-transform infrared spectroscopy. Further, the CuNPs were checked for antidiabetic activity using porcine pancreatic α-amylase and α-glucosidase inhibition followed by evaluation of mechanism using circular dichroism spectroscopy. CuNPs were found to be predominantly spherical in nature with a diameter ranging from 1 to 5 nm. The phenolics and flavonoids in the extracts might play a critical role in the synthesis and stabilization process. Significant change in the peak at ∼1095 cm-1 corresponding to C-O-C bond in ether was observed. CuNPs could inhibit porcine pancreatic α-amylase up to 30% to 50%, while they exhibited a more significant inhibition of α-glucosidase from 70% to 88%. The mechanism of enzyme inhibition was attributed due to the conformational change owing to drastic alteration of secondary structure by CuNPs. This is the first study of its kind that provides a strong scientific rationale that phytogenic CuNPs synthesized using G. glauca and P. zeylanica can be considered to develop candidate antidiabetic nanomedicine.