Development of a bio-synthesized zinc oxide nanoparticle sensor for the quantification of totarolone in Tetraclinis articulata

Diterpenoids such as totarolone exhibit significant bioactivity, making their accurate quantification in plant extracts essential for pharmacological studies and quality control. Conventional analytical methods are often time-consuming, costly, or environmentally demanding, highlighting the need for rapid, sensitive, and eco-friendly alternatives. In this work, we report the electrochemical quantification of totarolone, a bioactive diterpenoid, in Tetraclinis articulata extract using a carbon paste electrode modified with green-synthesized zinc oxide (bio-ZnO) nanoparticles. Bio-ZnO was prepared via a plant-mediated route using Calamintha nepeta extract, providing a sustainable and eco-friendly alternative to conventional chemical synthesis. XRD analysis revealed that the bio-ZnO nanoparticles possess a hexagonal wurtzite structure with an average crystallite size of ∼10 nm. The modified electrode exhibited enhanced sensitivity and stability, enabling the effective detection of totarolone by cyclic voltammetry (CV) and square wave voltammetry (SWV). A linear analytical response was obtained, with a LOD of 1.19 μM, a LOQ of 3.98 μM and a measured concentration of 0.133 mM in the plant extract. These findings highlight the potential of green nanomaterial-based electrochemical sensors for the reliable and sustainable analysis of bioactive compounds.