Antiparasitic effect of limonene, a monoterpene compound found in the essential oils against Giardia lamblia

The present work aimed to assess the anti-parasitic effects of limonene (LMN) against Giardia lamblia trophozoites and cysts.

Anti-Giardia activities of LMN (25, 50, and 100 μg/mL) were assessed against G. lamblia cysts and trophozoites for 15-360 minutes. The effects of LMN on the apoptosis stimulation G. lamblia parasites were determined by colorimetric protease assay.

Giardia trophozoites were more sensitive to LMN than cysts. The best effect of LMN was seen at 100 μg/mL. LMN markedly triggered caspase-3 activity by 10.2%, 25.3%, and 36.1%, respectively (P < 0.001).

We found the potent in vitro anti-giardia activity of LMN against G. lamblia parasites with the maximum activity at 50 and 100 μg/mL. However, additional surveys are necessary to reveal the specific efficacy, mechanisms, and safety of LMN.