Metabolite Profiling and Biological Activity Assessment of Casuarina equisetifolia Bark after Incorporating Gold Nanoparticles

OBJECTIVE: Casuarina equisetifolia bark is rich in various active metabolites and selected to be studied due to limitation of the synthetic antioxidants that have adverse side effects. The present study aimed to enhance efficiency of the most effective extract by incorporating gold nanoparticles (Au-NPs). METHODS: The phytochemical and biological measurements were carried out in total methanolic extract and its successive fractions. Moreover, these measurements were assayed in the most effective extract after incorporating Au-NPs. RESULTS: The study revealed that total methanolic extract exhibited the highest biological and cytotoxic activities as compared to other fractions. Therefore, it is considered as good candidate for nano-extract preparation. The methanolic extract incorporated with Au-NPs showed higher antioxidant, scavenging and cytotoxic activities in addition to higher inhibitory effect against α-amylase activity as compared to native extract itself. To pinpoint active agents in total methanolic extract, the secondary metabolite profiling via HPLC-MS showed that 33 and 17 metabolites were annotated in the extract before and after incorporating Au-NPs, respectively. The median lethal dose (LD(50)) showed that gold total methanolic nano-extract is safer than total methanolic extract. CONCLUSION: This study concluded that total methanolic C. equisetifolia bark extract is a valuable bioresource to synthesize an eco-friendly Au-NPs with health-enhancing effect as antioxidant, antidiabetic and cytotoxic agents. The present study is considered as the first report on utilization of C. equisetifolia bark in synthesis of Au-NPs by mean of green nanotechnology and investigation of its biological activity in relation to its metabolite fingerprint.