TOXICOLOGICAL EVALUATION OF LAVANDULA DENTATA ESSENTIAL OIL IN THE ALTERNATIVE MODEL CAENORHABDITIS ELEGANS

Resumo

INTRODUCTION: Aromatherapy with lavender essential oil (EO) has become a relevant therapeutic practice, especially due to the anxiolytic effect of Lavandula angustifolia EO. However, the species Lavandula dentata, common and widely cultivated in Rio Grande do Sul, has been used for the same purpose despite the lack of scientific evidence regarding its efficacy and safety. EOs are produced by plants as a defense mechanism and adaptation to their environment, leading to chemical variations depending on the habitat. These variations can result in high concentrations of potentially toxic compounds. Therefore, it is essential to understand the toxicity of these EOs used by the population. OBJECTIVE: To evaluate the toxicity of Lavandula dentata essential oil using the alternative model Caenorhabditis elegans from a municipality in the Vale do Rio Pardo region. MATERIALS AND METHODS: The nematode strain used was N2 (wild type), fed with Escherichia coli OP50, and maintained in the bioanalysis laboratory at Feevale. After synchronization, 100 L1-stage nematodes were exposed in liquid medium to L. dentata EO. After 1 hour, the nematodes were transferred to NGM plates containing E. coli. The nematodes were exposed to the following linalool concentrations: 72, 108, 144, 180 and 216 µg/mL, and to 1,8-cineole concentrations: 264, 396, 529, 661, and 793 µg/mL. The control group was treated with an ethanolic solution. After 48 hours, survival rate and body length parameters were evaluated. RESULTS AND CONCLUSION: Toxicity assessment using the C. elegans alternative model showed that the EO causes significant developmental differences in nematodes starting at linalool concentration (45 μg/mL) and 1,8-cineole (160 μg/mL). It was found that the increase in concentrations of linalool and 1,8-cineole is directly related to the reduction in nematode survival rate, with an LC50 of 115 μg·mL⁻¹ for linalool and 421.7 μg·mL⁻¹ for cineole. These data reinforce the importance of assessing the safety of essential oil use, especially those with compositions that vary according to their region of origin.