About 1.5 billion people are estimated to be infected with soil-transmitted helminths (WHO 2022), which are considered as one of the most widespread human pathogens. In the quest to find safe and effective anthelmintic drugs, a keen interest in ethnomedicinal studies have emerged in recent years. Plants and/or their secondary metabolites may serve as alternative anthelmintics, which can surmount manifold regulatory challenges and consequences caused by synthetic anthelmintics. Owing to these merits, several medicinal plants have been explored for their anthelmintic properties (Tandon et al. 2011).
Persicaria hydropiper (L.) Delarbre (Polygonaceae), called locally as “nhachü”, is an annual herb of about 40-70 cm height. It is found distributed in temperate and tropical Asia, Northern Africa, Australia and in many regions of Europe (Huq et al. 2014), besides in the Northeast India (Hazarika and Sarma 2006). In the traditional medicine of Pakistan, P. hydropiper has been used for a long time against inflammation, rheumatoid arthritis, epilepsy, headache, colic pain, fever, chill, joint pain, oedema and infectious diseases (Ayaz et al. 2015). Recent experimental studies on this plant have also established it to possess diverse biological activities, including anticholinesterase, antioxidant and gastroprotective activities (Ayaz et al. 2017). Ayaz et al. (2014) has reported the anthelmintic activity of whole plant extract of P. hydropiper, using adult earthworms (Pheretima posthuma) and roundworms (Ascaridia galli), as test organisms. It can be argued here that the anthelmintic data generated using earthworms as test organisms, possess only limited scope, as earthworms are the free-living organism, with a different structural and functional body organization than parasitic roundworms (Tandon et al. 2011).
During our recent ethnomedicinal studies, it was revealed from field surveys that the leaves of P. hydropiper (Fig. 1) are used by the Angami tribe of Nagaland, India as a common remedy to treat the intestinal worms. The present study was initiated to investigate the anthelmintic properties of P. hydropiper leaves, using Raillietina echinobothrida, the intestinal cestode parasite of domestic fowl. The motility and/or mortality of the worms and alterations in body surface of parasite, as evident by scanning electron microscopy, following exposure of parasites to methanol leaves extract of plant, were the parameters of present study.