Preparation and characterization of O/W nanoemulsion with eucalyptus essential oil and study of in vitro antibacterial activity

摘要

Objective(s): Eucalyptus oil is a typical essential oil used in pharmaceutical, food, cosmetic and drug industries having antimicrobial and antioxidant activities. Eucalyptus oil is highly unsteady and hydrophobic under normal conditions, so easily lose its bactericidal activity. To protect this bioactive herbal product, nanoemulsion technology is an excellent way to micro-encapsulate and hydrophilize it. Due to special properties, oil-in-water (O/W) essential oil nanoemulsions are expanding day by day as a delivery system in food, cosmetic and agrochemical industries. The aim of the present study is to prepare eucalyptus oil based nanoemulsions, its characterization and in vitro evaluation of its antimicrobial activity. Methods: O/W nanoemulsions were prepared by using eucalyptus essential oil in the presence of surfactants like tween 20, tween 80 and sodium dodecyl sulphate (SDS). Physiochemical parameters like pH, conductivity, optical density and antibacterial activity were studied. Stability of nanoemulsions was studied for 120 days. Results: Nanoemulsions prepared with tween 20/80 and SDS were smaller in size than those prepared with tween 20/80. Formulated nanoemulsions were stable even after 120 days as no significant change in pH, conductivity, size of droplet was observed. Substantial in vitro antibacterial activity against Bacillus subtilis was observed with nanoemulsions prepared with tween 20 only. Conclusion: The findings suggested that eucalyptus oil based nanoemulsions can be used as key drug carrier in pharmaceutical, food and cosmetic industries.