Background: Nowadays, interest in the use of herbs for medical purposes is increasing. The most
frequently used chemotherapeutics for treating chronic toxoplasmosis showed a variety of side effects.
Therefore, it is crucial to discover new alternative therapy from natural products.
Objective: To evaluate the in vivo effect of Eugenia caryophyllata aqueous extract alone or combined with
Spiramycin© against chronic toxoplasmosis.
Material and Methods: The study utilized 50 mice, equally divided into five groups. They included the
normal control group (GI), infected control group (GII), Spiramycin©-treated group (GIII), E. caryophyllatatreated
group (GIV), and Spiramycin© combined with E. caryophyllata treated group (GV). Treatment
started six weeks after the infection and continued for 15 d. Parameters used for evaluation included
parasitological, and histopathological assessments. As well, an immunohistochemical study was conducted
to measure expression levels of tumor growth factor-β (TGFβ), inducible nitric oxide synthase (iNOS), and
phosphorylated signal transducer and activator of transcription 1 (pSTAT-1). Interleukins 10 and 12 (IL-
10, IL-12), and liver enzymes (ALT and AST) were also measured.
Results: Brain cyst counts significantly decreased in all treated groups. Combined treatment was better
than Spiramycin© alone. Mice receiving E. caryophyllata alone or combined with Spiramycin© showed
improvement in the histopathological changes in all examined tissues, with decreased expression levels
of TGFβ, iNOS, and pSTAT-1. Additionally, there was an increase in IL-12 level in the combined treatment
group, and a decrease in the IL-10 level. Moreover, combined treatment reduced the high levels of liver
enzymes (ALT and AST).
Conclusion: E. caryophyllata extract exhibited promising potential in vivo activity against chronic
toxoplasmosis.