Anthelmintic effects and toxicity of Cynodon dactylon (L.) Pers. in rodent models

Abstract

Background: Cynodon dactylon (L.) Pers. is a very widely distributed medicinal herb. Different preparations from this herb are extensively used as a folk medicine in the Middle East, including Turkey, besides in India, Italy, etc. In India, the grinded juice of C. dactylon has been commonly used as a folk medicine for the treatment of intestinal-worm infections. Aim: This study was undertaken to investigate the in vitro and in vivo anthelmintic effects and potential toxicity of whole plant extract of C. dactylon against Hymenolepis diminuta (Hymenolepididae), a zoonotic tapeworm, using two rodent models. Materials and Methods: In in vitro assay, plant extract was tested at 10, 20 and 40 mg/ml concentrations, against adult H. diminuta, and the efficacy was adjudged by physical motility and mortality of parasites. In vivo testing was done in H. diminuta - Wistar rat model, by monitoring the eggs per gram of faeces (EPG) count and worm counts of animals after treatment with 200, 400, and 800 mg/kg doses of extract. Acute toxicity of extract was monitored with 2000 mg/kg oral dose of extract, following the OECD guidelines in Swiss albino mice. In sub-acute toxicity, a low extract dose, i.e. 400 mg/kg and a high extract dose, i.e. 800 mg/kg was tested in mice, as per the guidelines of OECD, for the assessment of some haematological and biochemical parameters of mice. Results: The extract showed a dose-dependent efficacy in both, the in vitro assay as well as in the in vivo assay. In the in vitro test, the 40 mg/ml concentration of extract caused paralysis and mortality of worms in as early as in 4.12 ± 0.55 h and 5.16 ± 0.34 h, respectively. This was comparable with the reference drug praziquantel (PZQ). The in vitro anthelmintic effects were also corroborated by the results of in vivo assay, wherein treatment of rats with 800 mg/kg dose of extract for 5 days revealed up to 77.64% reduction in EPG counts and 79.00% reduction in worm counts at post-treatment period, showing a comparable efficacy with 5 mg/kg dose treatment of PZQ. In the acute toxicity assay, the extract did not reveal any adverse effects or mortality in any animal, during the 14-days observation period. The LD50 of extract was estimated to be greater than 2000 mg/kg. In the sub-acute toxicity study, all the studied parameters of animals were found to be normal at 400 mg/kg dose (low dose), however, treatment with high dose, i.e., 800 mg/kg revealed only a slight elevation of aspartate aminotransferase (AST) in animals. Conclusion: C. dactylon possesses significant anthelmintic properties, and its extract appears to be devoid of any major adverse effects in experimental animals. These pharmacological credentials supports the safe folkloristic use of this plant as an anthelmintic remedy.