Scolicidal Potential of Tribulus terrestris L. Aqueous Fruit Extract: An In Vitro Study on Echinococcus granulosus Protoscolices

Abstract

Cystic Echinococcosis (CE) is a global health and economic challenge, and its current treatments necessitate the development of safer and more effective therapeutic alternatives. This study aimed to evaluate the in vitro scolicidal efficacy of the aqueous fruit extract of Tribulus terrestris L. against protoscolices of Echinococcus granulosus sensu lato.A dry aqueous extract of T. terrestris fruits was prepared, and preliminary qualitative phytochemical screening for its major phytoconstituents was conducted. A separate hydro-ethanolic extract was also analyzed using Gas Chromatography-Mass Spectrometry (GC-MS). The efficacy of different concentrations of the extract dissolved in Phosphate Buffered Saline (PBS) (25, 50, 75, and 100 mg/mL) was evaluated against E. granulosus protoscolices at exposure times of 10, 20, 40, and 80 minutes, with estimation of the Lethal Concentration 50% (LC₅₀) and Lethal Time 50% (LT₅₀) values. Qualitative screening of the aqueous extract revealed the presence of important phytochemical groups such as flavonoids, saponins, phenolic compounds, tannins, and alkaloids. GC-MS analysis of the hydro-ethanolic extract primarily indicated the presence of fatty acids (such as linoleic acid and palmitic acid) and other compounds. The extract demonstrated significant concentration-dependent and time-dependent scolicidal activity (P < 0.001 for both, and for their interaction), with the final concentration of 100 mg/mL causing 100% mortality of protoscolices after 80 minutes. LC₅₀ values decreased with increasing exposure time (the lowest estimated value of ~32.3 mg/mL at 80 minutes), and LT₅₀ values decreased with increasing concentration (the lowest estimated value of 14.0 minutes at a final concentration of 100 mg/mL).The results of this study indicate that the aqueous fruit extract of T. terrestris possesses promising in vitro scolicidal efficacy against E. granulosus s.l. Protoscolicesare likely attributable to the combined and synergistic effects of their diverse phytochemical constituents. These findings support the potential for exploring this extract as a natural source for new or complementary therapeutic agents against cystic echinococcosis and warrant further in vivo studies and advanced phytochemical characterization.