Catharanthus roseus extract mediated synthesis of cobalt nanoparticles: evaluation of antioxidant, antibacterial, hemolytic and catalytic activities

Abstract

In the recent work, synthesis of cobalt nanoparticles (CoNPs) was carried out by using whole plant extract of Catharanthus roseus. The average particle size of CoNPs calculated by XRD studies was found to be 27.08 nm. In assessment of antioxidant activity, DPPH radical scavenging percentage values of 37.05% and 79.19% were observed at 125 µg/ml and 1000 µg/ml nanoparticle concentration respectively. CoNPs exhibit greater growth inhibition percentage against gram negative bacteria in comparison to gram positive bacteria. In hemolytic assay, prepared nanoparticles depicted hemolysis rate of 1.53%. The surface of green synthesized CoNPs was modified with cetyltrimethylammonium bromide (CTAB) as a cationic surface modifier. Furthermore, the unmodified and modified CoNPs were studied for degradation of toxic alizarin red S dye in aqueous media. Best dye degradation results were observed at pH 6 with nanoparticle dosage of 10 mg and at lower concentration value of dye.