Background: Essential oils (EOs) are natural volatile plant extracts that have different
biological activities including antiproliferative potentials.
Objective: The current study aims at evaluating the antiproliferative activities against some cancer
cell lines of six EOs in their neat oily state and in water-based microemulsions where the EOs exist
as nanoparticles. The EOs included marjoram (Origanum majorana), turmeric (Curcuma longa),
sweet basil (Ocimum basillicum), clove buds (Syzygium aromaticum), geranium (plargonium
graviolenis), and black cumin (Nigella sativa).
Method: GC-MS chromatographic analysis was used to reveal the chemical composition of EOs.
Self-microemulsification method and oil titration method were used for the fabrication of the different
microemulsions. MTT assay and IC50 determinations were used for evaluating the extent of the
Results: Results indicated that geranium EO was the most active against the evaluated cancer cell
lines followed by basil EO and marjoram EO. On the other hand, turmeric followed by black cumin
EOs showed the least antiproliferative activity relative to the other EOs. Clove EO showed selective
activity depending on the type of cancer cell lines. Formulation of these EOs in microemulsions led
to the development of water-borne nanoparticles having an average particle size from 10.7nm
to 18.0 nm depending on the type of EO. Re-evaluation of the antiproliferative activity of these
EOs after microemulsification showed differential behavior ranging from activity enhancement to
retardation relative to the original activity of each corresponding neat EO in its oily state. Potential
factors that could justify the obtained results are discussed.
Conclusion: Some EOs and their microemulsions may potentially be used as natural adjuvants to
classical anti-cancer drugs.