Anti-plasmodial activity of fractions 1–3 of Satureja thymbra EO. Fractions were dissolved in DMSO and then diluted with a medium to achieve the required concentrations (final DMSO concentration <1%, which is non-toxic to the parasite). Asynchronous cultures with parasitaemia of 1–1.5% and 1% final haematocrit were aliquoted into the plates and incubated for 72 hrs at 37°C. Parasite growth was determined spectrophotometrically (OD650) by measuring the activity of the parasite lactate dehydrogenase (LDH). IC50 is the mean ± standard deviation of three separate experiments performed in duplicate. # statistically different vs A; * statistically different vs B; ° statistically different vs C. CQ was used as reference compound (IC50 7.0 and 110 ng/ml on CQ-S and CQ-R strains, respectively).