The Therapeutic Effects of Lycopene Against Experimental Giardiasis in Mice

<i>Giardia duodenalis</i> is a protozoan parasite that infects approximately one billion people worldwide. In this study, the effects of lycopene on experimental giardiasis in mice were investigated by evaluating cyst shedding rate, weight changes, duodenal antioxidant status, and histopathological alteration. Ninety-five male mice aged four to six weeks were divided into six groups of 15 and one group of 5 as the negative control. All mice were infected with 2 × 10⁵ <i>Giardia duodenalis</i> (B genotype) cysts except for the negative control. The treatment groups were treated with metronidazole, mixed lycopene-metronidazole, and 5, 10, and 20 mg/kg lycopene for 7 days. The mice treated with lycopene 20 and mixed lycopene-metronidazole had no cyst shedding from the 7^th day of treatment. The mildest lesions were observed in the mixed lycopene-metronidazole group. Results showed that treatment with mixed lycopene-metronidazole significantly increased TAC and decreased MDA levels as compared with the positive control. It seems that the antigiardial effect of lycopene is related to its antioxidant properties. Nevertheless, direct effect of lycopene on <i>Giardia</i> and its probable mechanism remain to be investigated.