Anthelmintic activity of praziquantel and Spilanthes acmella extract on an intestinal cestode parasite

Spilanthes acmella Murr., popularised as toothache plant, is a well-known culinary and medicinal plant for different purposes, but its use as an anthelmintic is apparently exclusive to the Mizo people of India and Myanmar. A chloroform extract of Spilanthes acmella Murr. was analysed in a single quadrupole GC-MS system, from which it was found that the major compound was an alkylamide, N-isobutyl-(2E,4Z,8Z,10E)-dodecatetraenamide. A comparative study was performed on the anthelmintic activity of the plant extract and praziquantel (PZQ) against an intestinal cestode, Raillietina echinobothrida. In terms of efficacy, PZQ was more potent, but the plant extract was also effective at all concentrations tested. PZQ caused severe shrinkage and folds of the tegument, constriction of the suckers, dislocation of spines and erosion of microtriches. The plant extract caused shrinkage and folds on the main body but not on the scolex. Damage on the suckers is more pronounced than in PZQ-treated cestodes. The spines were completely removed. The current findings indicate that S. acmella is a good source of compounds with anthelmintic activity.