A Comparative Study on the Antioxidant and Insecticidal Activities of Eucalyptus camaldulensis Essential Oil and Hydrosol

The study investigates the hydrosol of Eucalyptus camaldulensis to assess its value and potential applications within the essential oil (EO) industry. Following steam distillation of E. camaldulensis leaves to extract essential oil, the resulting hydrosol underwent liquid-liquid extraction to yield a secondary essential oil (SEO). Comparative chemical analysis was performed using GC/MS. Comparative chemical analysis of the SEO and EO revealed distinct compositions, with 24 compounds identified in the SEO compared to 41 in the EO. Oxygenated compounds predominated in the SEO while non-oxygenated compounds were the most abundant in the EO (63.61%). Eucalyptol emerged as the primary constituent in both, with higher concentrations observed in the SEO (60.41%) than in the EO (28.53%). Additionally, antioxidant activity assessed using the DPPH assay demonstrated significant radical reduction in the SEO compared to the EO. In insecticidal tests targeting Callosobruchus maculatus, the SEO exhibited pronounced toxicity, with an IC₅₀ value lower than that of the EO. This study showed the abundance of oxygenated compounds in E. camaldulensis hydrosol compared to pure essential oil, suggesting its potential as an antioxidant agent and for integrated pest management in agriculture. The research highlights the value of hydrosols in the EO industry and their potential applications in natural product formulations and pest control strategies.