Caracterização química e avaliação da atividade antimicrobiana do óleo essencial de Ocimum basilicum L.

Background: Medicinal plants are important sources of bioactive compounds with therapeutic potential, and species of the Lamiaceae family are particularly recognized for their essential oils and pharmacological properties. In view of the increasing antimicrobial resistance, this study aimed to evaluate the antimicrobial potential and chemically characterize the essential oil of Ocimum basilicum L. Methods: Leaves of Ocimum basilicum L. were collected, dried, and subjected to hydrodistillation using a Clevenger apparatus for essential oil extraction. The chemical composition was analyzed by gas chromatography-mass spectrometry (GC-MS). The antimicrobial activity of the essential oil was evaluated by the broth microdilution method according to CLSI guidelines against Staphylococcus aureus (ATCC 25923 and ATCC 33951), Escherichia coli (ATCC 25922), Candida albicans (ATCC 90028), and clinical strains of Candida tropicalis, Candida krusei, and Candida glabrata, determining the minimum inhibitory, bactericidal, and fungicidal concentrations. (3) Results: The essential oil of Ocimum basilicum showed a yield of 0.14% (w/v), with 22 compounds identified by GC-MS. Estragole (66.29%), linalool (19.84%), and bergamotene (4.17%) were the major constituents, characterizing the oil as an estragole chemotype. No antimicrobial activity was observed against the tested bacterial and fungal strains, with MIC values above 1024 µg mL⁻¹. (4) Conclusions: The absence of antimicrobial activity observed in this study may be related to the different chemotype of the essential oil analyzed, highlighting the influence of chemical composition on its biological effects. Further pharmacological investigations are encouraged, as the compounds present in O. basilicum essential oils exhibit relevant therapeutic potential.