The effect of distillation methods on the yield, composition and biological activity of basil (Ocimum basilicum L.) essential oil

Basil (Ocimum basilicum L.) is an aromatic plant, well known for its characteristic scent and healing properties, which has a wide application, from cooking to alternative medicine. The objective of this work was to evaluate the chemical composition, antimicrobial and antioxidant activity of basil essential oil obtained by hydrodistillation, microwave-assisted hydrodistillation and solvent-free microwave-assisted hydrodistillation. Gas chromatography analysis showed that the main components present in all three essential oils were linalool (30.3-58.2%) and epi-a-cadinol (5.6-7.3%). The distillation method mainly affected the content of terpenes, and aromatic compounds. The essential oils expressed good antimicrobial activity, most effective against Escherichia coli ATCC 25922, while the Pseudomonas aeruginosa ATCC 27853 was the most resistant strain. Good antioxidant activity was established after 120 min of incubation for all obtained essential oils with a significant difference regarding the applied distillation method. The results showed a great influence of the distillation method on the chemical composition, detected compounds, as well as antioxidant potential and antimicrobial activity of basil essential oils. The use of microwave assisted hydrodistillation has shown a significant difference in oil yield, energy consumption and environmental impact, which makes it a more suitable distillation process compared to conventional hydrodistillation.