In vitro anthelmintic activity of glycyrrhetic acid against sheep gastrointestinal nematodes

The disease caused by gastrointestinal nematodes (GIN) is considered one of the most important health constraints affecting productivity in small ruminants1. Sheep GIN control programs rely mostly on the use of synthetic anthelminthics2. However, the anthelmintic resistance developed by these nematodes worldwide and the risk of residues in sheep products, have led to the need to find alternative treatments1. Among alternative strategies, there has been considerable and expanding interest in the search for effective and safe herbal dewormers3. The antifilarial potential of glycyrrhetic acid has been recently reported4. The present study was aimed to evaluate the in vitro anthelmintic activity on sheep GIN of 1% glycyrrhetic acid. From fresh faecal samples collected by ewes naturally infected by Haemonchus and Trichostrongylus nematodes, GIN eggs were isolated and cultivated. For the in vitro evaluation of the anthelmintic activity of 1% glycyrrhetic acid, the Egg hatch test, the Larval development test and the Larval mortality/paralysis test were used5,6. In each test, the activity of 1% glycyrrhetic acid was compared to untreated and treated (0.1% thiabendazole) controls. Six repetitions were made through the experiment and obtained data were statistically elaborated. In all tests, 1% glycyrrhetic acid gave results significantly different (P<0.01) from the untreated controls but showed no significant differences when compared to 0.1% thiabendazole. Results obtained in this study revealed 1% glycyrrhetic acid effectively targeted both the egg and larval developmental stages of sheep gastrointestinal nematodes and the anthelmintic activity of this compound was comparable to that of the reference drug.