Characterisation of gold nanoparticles synthesised by leaf and seed extract of Syzygium cumini L.

Abstract

Here, Syzygium cumini leaf extract (LE) and seed extract (SE) were explored for the synthesis of gold nanoparticles (GNP). LE and SE as well as their polar (water) fractions showed potential for GNP synthesis. Comparative synthesis kinetics and morphological characterisation studies revealed the synthesis of smaller sized GNP by LE than SE. Only polar (water) fractions showed potential for GNP synthesis, which are smaller in size compared to their respective extracts. SE contained more polyphenols and biochemical constituents than LE and therefore, showed higher synthesis rate and bigger sized GNP. Atomic force microscope and scanning electron microscope analysis indicated that both extracts and their fractions catalysed the synthesis of spherical GNP. The average size of GNP synthesised by LE, leaf water fraction (LWF), SE and seed water fraction (SWF) were 24, 23, 35 and 32 nm, respectively. Fourier transform infrared analysis identified the biomolecules involved in the synthesis and stability of GNP. This study documented the potential of S. cumini for the synthesis of GNP in addition to silver nanoparticles (SNP). However, nature and types of polyphenols involved in GNP synthesis seem to be different from that involved in SNP synthesis. This might be the possible reason for smaller sized GNP that SNP.