antiparasitic effect of limonene, a monoterpene compound found in the essential oils against giardia lamblia

Introduction: the present work aimed to assess the anti-parasitic effects of limonene (lmn) against giardia lamblia trophozoites and cysts. methods: 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. results: 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). conclusion: 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.