Luteolin, a naturally occurring plant flavonoid, has antioxidant, anti-amoebic, antitrypanosomal, and antimalarial activities. In this study,
the inhibitory effects of luteolin were microscopically evaluated against three Babesia species and Theileria equi in vitro and against B. microti
in mice. Reverse-transcription PCR was used to evaluate the effect of luteolin on transcription of DNA gyrase subunits A and B genes.
Luteolin significantly inhibited the growth from an initial parasitemia of 1 % for Babesia bovis, Babesia bigemina, Babesia caballi, and Theileria
equi with IC50 values of 81, 79, 90, and 99 nM, respectively. Parasite regrowth was inhibited at 100 μM in the subsequent viability test.
Luteolin treatment of B.bovis cultures inhibited the transcription of the DNA gyrase subunit B gene. Luteolin at a dosage of 5 mg/kg resulted
in a 77.5 % inhibition of Babesia microti growth in BALB/c mice. Luteolin might be used for drug therapy in babesiosis.