Elucidation of synergistic effect of eucalyptus globulus honey and Zingiber officinale in the synthesis of colloidal biogenic gold nanoparticles with antioxidant and catalytic properties

Abstract

Natural ingredients including plants and biological materials can be used in the synthesis of colloidal gold nanoparticles (AuNPs) to fulfil the needs of safe, biocompatible AuNPs for life science applications. Despite many attempts on green synthesis of AuNPs, stable biogenic AuNPs has yet to be mass produced in the market due to the aggregation of the particles. This study provides a simple one-pot method in synthesising colloidal AuNPs using eucalyptus globulus honey and Zingiber officinale (ginger) as reducing and stabilising agents. The synthesised colloidal AuNPs exhibited well-dispersed spherical morphology with average diameter of 14.5 nm and 14.1 nm for honey-reduced colloidal AuNPs (H6) and honey-reduced/ginger-stabilised colloidal AuNPs (H6G5) respectively. Significant increase in DPPH and hydroxyl radical scavenging activities were found in H6G5 compared to H6 which indicate a prominent antioxidant property of the colloidal AuNPs. The reduction of 4-nitrophenol with the aid of the colloidal AuNPs recorded a reaction time of 28 min and 62 min for H6G5 and H6 respectively compared to 240 min of reaction without the addition of catalyst. The excellent properties of these colloidal AuNPs suggest a simple method for biogenic synthesis. Hence, the synthesised colloidal AuNPs can be further exploited for biomedical and life science applications.