Therapeutic efficacy of Zanthoxylum rhetsa DC extract against experimental Hymenolepis diminuta (Cestoda) infections in rats.

Zanthoxylum rhetsa DC (Rutaceae), commonly called prickly ash, is used in the folk medicine of Naga tribes in India as a deworming remedy. In the present study, the therapeutic efficacy of Z. rhetsa leaf extract was investigated against experimental Hymenolepis diminuta (Cestoda) infections in albino rats. The efficacy of extract was determined on the basis of reduction in the eggs per gram of feces (EPG) counts and worm load following treatment with 100, 200, 400 and 800 mg/kg, p.o. doses of plant extract. For comparison's sake, animals were also treated with a reference drug, praziquantel at 5 and 25 mg/kg body weight doses. Three treatment regimes were followed to monitor the effects of extract on cestode parasite: (1) Treatment on day 2-4 postinoculation (pi) of cysticercoids against the larval stages; (2) treatment on day 8-10 pi against the immature stages; and (3) treatment on day 21-25 pi against the adult stages of parasite. The extract revealed its maximum efficacy against the larval stage, where its 800 mg/kg dose showed a worm count reduction of 86.60%, compared to 80.00% by the reference drug, praziquantel (5 mg/kg dose). The EPG counts also decreased drastically from 23,389 ± 2,372 to 0 in the same treatment group, compared to 33,161 ± 1,383 recorded in the control group. The efficacy of extract was found to be of moderate level against the immature and adult stages of parasite. The present investigation holds the evidence that the leaves of Z. rhetsa possess significant anticestodal property and supports its use in folk medicine.