Phenolic compounds play a very important role in human life because of their antioxidant activity which can prevent harmful diseases caused by free radicals. In the present work, we have synthesized some Schiff bases by the reaction of different hydroxybenzaldehydes and primary aromatic diamines using StannousChloride (SnCl₂·2H₂O) as the catalyst. The products were characterized by FT-IR spectroscopy, GCMS and NMR spectroscopy. Furthermore, the antioxidant activity of the Schiff bases were determined by using DPPH assay and ABTS assay and the results were compared with a standard compound, trolox as well as with the parent aldehydes. The synthesized compounds were found to have better antioxidant activity than their corresponding parent aldehydes.

Curcumin [(1E, 6E)-1,7-bis(4-hydroxy-3-methoxy-phenyl)-1,6-heptadiene-3,5-dione] is a low molecular weight yellow-orange polyphenolic pigment extracted from the powdered rhizome of Curcumalonga. Curcumin has wide medicinal applications as an antioxidant, anti-inflammatory, cancer chemopreventive,and potentially chemotherapeutic agents as well as stabilizer/reducing agent in silver nanoparticles (AgNPs) synthesis. However, the low solubility of curcumin in aqueous solutions limits its applications and also, many of AgNP synthetic processes lack a greener synthetic route. In the present work, a Schiff base ofcurcumin is synthesized condensing curcumin and 1,4-diaminobutane in 2:1 ratio. The resulting product shows improvement in solubility in water and favours the synthesis of AgNPs in aqueous medium at room temperature,acting as a self-reducing/stabilizing agent. This proposed synthetic route is simple, feasible and green. The size and morphology of AgNPs are analyzed by TEM, SEM, EDS and XRD techniques. The recyclable AgNPs as a heterogeneous catalyst in the reduction of nitroaromatics to amino compounds is environmentally benign andcan be re-used up to 5^th cycle without considerable loss of its catalytic activity. Moreover, both Cur-1,4 and AgNPs show bactericidal properties against bacterial strains (Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa) which find medicinal importance in future