of analytical grade and used without any modification. Curcumin, phosphate-buffered
saline (PBS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), mercury(II) chloride,
lead(II) nitrate, ferrous sulfate heptahydrate, cobalt(II) nitrate
hexahydrate, zinc nitrate hexahydrate, ferric chloride anhydrous,
and sodium hydroxide (NaOH) were brought from Himedia Laboratories
Pvt. Ltd., India, whereas calcium chloride, copper sulfate, and magnesium
chloride were provided by SRL (Sisco Research Laboratories) Pvt. Ltd.,
India. Cadmium acetate and silver nitrate were received from Merck
Ltd., India. Solvents like hydrochloric acid (HCl) and N-dimethylformamide (DMF) were from Rankem Pvt. Ltd., India. Nickel(II)
acetate tetrahydrate was acquired from Sigma-Aldrich, USA. Listed
solvents such as methanol and dimethyl sulfoxide (DMSO) were received
from SD-Fine Chemicals Limited (SDFCL), India. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium
bromide (MTT) was procured from Amresco, USA. Lastly, quinine sulfate
was purchased from Loba Chemie Pvt. Ltd., India. Ultrapure water was
used to prepare all the solutions.