Evaluation of the Toxicity, Morphological and Behavioural Effects of <i>Pelargonium graveolens</i> Essential Oil in <i>Artemia franciscana</i> , Along With Its Antimicrobial Activity

ABSTRACT Essential oils (EOs) are complex mixtures of volatile, lipophilic compounds with characteristic aromas, widely employed for the treatment of conditions such as fungal infections, seborrheic dermatitis, respiratory disorders, and neuropsychiatric disturbances. However, studies systematically evaluating effective concentrations in relation to potential adverse effects remain scarce. This study aimed to investigate the toxicological profile of two commercial EOs (G1 and G2) derived from Pelargonium graveolens . The chemical composition of the oils was characterized using comprehensive one‐ and two‐dimensional gas chromatography (GC × GC/TOF‐MS). Toxicity was assessed through exposure of cysts and nauplii of Artemia franciscana to increasing EO concentrations, followed by behavioural, biochemical, morphological, and antimicrobial analyses. Chromatographic profiling revealed 187 compounds in one oil and 224 in the other, indicating marked compositional variability. Toxicity assays in A. franciscana demonstrated a reduction in cyst hatching rates and increased naupliar mortality for both EOs, particularly at higher concentrations. In addition, locomotor activity was significantly reduced in nauplii exposed to elevated concentrations of G2. Biochemical analyses showed increased production of reactive oxygen species at 1% and 5% in both EO groups, while morphological assessment revealed structural abnormalities, especially at 5%. Furthermore, higher EO concentrations inhibited the growth of Gram‐positive and Gram‐negative bacteria, as well as yeast strains. Collectively, these findings indicate that P. graveolens essential oils exhibit concentration‐dependent toxicity. Although these oils demonstrate antimicrobial activity, their indiscriminate use at elevated concentrations may pose significant risks to human health.