Background: Natural products and their secondary metabolites are a good source of pharmacologically active constituents and have been widely developed into modern medicines. The research aims to use an essential oil from eucalyptus and then formulate a nanoemulsion. It would be characterized and evaluated for its in vitro anti-trypanosomal activity against Trypanosoma brucei (a parasite endemic in developing and most African countries).

Material and Methods: Several batches of the eucalyptus oil nanoemulsion were produced using Tween 80 and/or Span 80 as surfactants, in different proportions. The batches were characterized for in vitro anti-trypanosomal activity against Trypanosoma brucei using contaminated blood smears from Wistar rats. The nanoemulsions were also analyzed for particle size, polydispersity index, pH, and viscosity. The eucalyptus oil used for the formulation was also evaluated using gas chromatography-mass spectroscopy (GC-MS).

Results: The nanoemulsion possessed a concentration-dependent anti-trypanosomal activity and had a similar result to the positive control (commercially available standard). The eucalyptus oil analysis revealed the presence of aromandendrene, alloaromadendrene, methyl palmitate, 7-octadecenoic acid methyl ester, eucalyptol, and other organic compounds.

Conclusions: The eucalyptus oil nanoemulsion demonstrated strong trypanocidal efficacy against Trypanosoma brucei and was comparable to the positive control.