In this study, leaves of three indigenous varieties of Mulberry namely, Morus alba L., Morus nigra L. and Morus rubra L. were investigated for their antioxidant potential and their proximate composition was determined. The yields of 80% methanolic extracts ranged between 8.28–13.89%. The contents of total phenolics (TPC), total flavonoids (TFC) and ascorbic acid (AA) ranged between 16.21–24.37 mg gallic acid equivalent (GAE)/g, 26.41–31.28 mg rutin equivalent (RE)/g and 0.97–1.49 mg/g, respectively. The antioxidant activity of leaf extracts was evaluated by measuring 1,1-diphenyl-2-picrylhydrazyl (DPPH^•) radical scavenging actity, 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulphonic acid (ABTS^•+) radical cation scavenging capacity and ferric ion reducing power and values ranged between 1.89–2.12, 6.12–9.89 and 0.56–0.97 mM Trolox equivalent/g of dried leaves, respectively. The investigated features reveal good nutritive and antioxidant attributes of all the varieties with mutually significant differences.

In this study, NiO nanostructures were synthesized via a hydrothermal process using ascorbic acid as doping agent in the presence of ammonia. As prepared nanostructures were characterized using Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Brunauer–Emmett–Teller (BET) specific surface area analysis, and thermogravimetric analysis (TGA). These analyses showed that these nanostructures are in the form of cotton-like porous material and crystalline in nature. Furthermore, the average size of these NiO crystallites was estimated to be 3.8 nm. These nanostructures were investigated for their potential to be a highly sensitive and selective enzyme-free sensor for detection of urea after immobilizing on a glassy carbon electrode (GCE) using 0.1% Nafion as binder. The response of this as developed amperometric sensor was linear in the range of 100–1100 μM urea with a R² value of 0.990 and limit of detection (LOD) of 10 μM. The sensor responded negligibly to various interfering species including glucose, uric acid, and ascorbic acid. This sensor was applied successfully for determining urea in real water samples such as mineral water, tap water, and river water with acceptable recovery.