Anthelmintic Activity of Crude Extract and Essential Oil of Tanacetum vulgare (Asteraceae) against Adult Worms of Schistosoma mansoni

Schistosomiasis, a parasitic disease caused by trematode flatworms of the genus Schistosoma, affects more than 200 million people worldwide, and its control is dependent on a single drug, praziquantel. Tanacetum vulgare (Asteraceae) is used in folk medicine as a vermifuge. This study aimed to investigate the in vitro schistosomicidal activity of the crude extract (TV) and the essential oil (TV-EO) from the aerial parts of T. vulgare. TV-EO was obtained by hydrodistillation and analyzed by GC/MS, which allowed the identification of beta-thujone (84.13%) as the major constituent. TV and TV-EO, at 200 mu g/mL, decreased motor activity and caused 100% mortality of all adult worms. At 100 and 50 mu g/mL, only TV caused death of all adult worms, while TV-EO was inactive. TV (200 mu g/mL) was also able to reduce viability and decrease production of developed eggs. Confocal laser scanning microscopy showed morphological alterations in the tegument of the S. mansoni surface after incubation with TV (50 and 100 mu g/mL). Quantitative analysis on the schistosomes tegument showed that TV caused changes in the numbers of tubercles of S. mansoni male worms in a dose-dependent manner. The findings suggest that T. vulgare is a potential source of schistosomicidal compounds.