Anthelmintic activity of a standardized extract from the rhizomes of Acorus calamus Linn. (Acoraceae) against experimentally induced cestodiasis in rats

BACKGROUND: The rhizomes of a herb Acorus calamus Linn. (Acoraceae) have been widely used as a traditional medicine to cure intestinal-helminthic infections in India and South Africa. AIM: This study was undertaken to investigate the in vivo anthelmintic activity of a standardized methanolic extract obtained from the rhizomes A. calamus in a rodent model. MATERIALS AND METHODS: A methanolic extract obtained from rhizomes of A. calamus was characterized for active principle using nuclear magnetic resonance (1)H NMR, (13)C NMR, mass and infrared spectroscopy. The amount of active principle in rhizome isolated active fraction of plant was assayed using high-performance liquid chromatography (HPLC). Later, the standardized rhizome extract of plant and its active principle were tested for in vivo anthelmintic efficacy against experimentally induced Hymenolepis diminuta, a zoonotic cestode, infections in rats. RESULTS: The study revealed that b-asarone is the active principle of plant. The HPLC analysis of local variety of A. calamus revealed that active fraction contains 83.54% (w/w) of b-asarone. The in vivo study revealed that treatment of H. diminuta infected rats by a single 800 mg/kg dose of rhizome extract for 5 days results into 62.30% reduction in eggs per gram of feces counts and 83.25% reduction in worm counts of animals. These findings compared well with the efficacy of a reference drug, praziquantel. The active principle b-asarone showed slightly better anthelmintic effects than crude extract. In acute toxicity assay, a single oral 2000 mg/kg dose of extract did not reveal any signs of toxicity or mortality in mice, and the LD50 of the extract was noted to be >2000 mg/kg. CONCLUSION: Taken together, the results of this study indicate that rhizomes of A. calamus bear significant dose-dependent effects against intestinal helminths. Further, the Indian variety of A. calamus contains high b-asarone content. Therefore, there exists a great potential to develop some suitable anthelmintic herbal products from this plant.