The in Vitro Antischistosomal Activity and Genotoxicity of the Active Ingredients of Allium sativum (allicin) and Curcuma longa (curcumin)

Abstract

Background: In this study, we assessed the in vitro antischistosomal activity of the active ingredients of Allium sativum (allicin) and Curcuma longa (curcumin) on Schistosoma mansoni.

Methods: This study was conducted in Faculty of Science, Port said University, Egypt (2018). Adult worms were exposed to a range of concentrations of AL or CU, and worm survival was assessed 24 h post-exposure to calculate the lethal concentration of the compounds. Scanning electron microscopy was used to assess ultrastructural changes in the surface of AL- or CU- treated worms. The genotoxicities of AL and CU on S. mansoni were determined by DNA fragmentation analysis.

Results: We determined the concentrations of AL and CU required to kill 50% of S. mansoni (LC₅₀ ). The LC₅₀ of AL was 8.66 μL/mL, whereas 100% mortality of S. mansoni was achieved by AL at concentrations of 50 μL/mL. The LC₅₀ of CU was 87.25 μL/mL, with the highest mortality of 91.3% seen after 24 h exposure to 100 μg/mL CU. Ultrastructural studies revealed that exposure to either AL or CU led to mild or severe surface damage to S. mansion, respectively. The degree of damage in the worms was sex-dependent. Interestingly, while CU exposure resulted in DNA fragmentation in S. mansoni worms, we observed no genotoxic effects of AL.

Conclusion: Both AL and CU exhibit antischistosomal activity; the study provided evidence suggesting that these compounds act through distinct mechanisms. These promising results encourage further investigation into these compounds as potential antischistosomal agents, either alone or as complementary treatments to praziquantel.

Keywords: Allicin; Curcumin; DNA; Schistosoma mansoni; Ultrastructural.

Fig. 1:

Scanning electron micrographs of untreated control S. mansoni and S. mansoni exposed to an LC50 of AL or CU. Images are shown of the male tegument (A-F) and gynecophoral canal (G-I), and the female tegument (J-L). tu - tubercles, black arrows - intertubular ridges, sp - spines, white arrow - swelling, gc - gynecophoral canal, black arrow head - protuberances, white arrow head - dimples. Higher magnifications are shown as inset images (7988X, scale bar, 10μm) and (6000X, scale bar 20 μm).

Fig. 2:

Electrophoretic separated genomic DNA from S. mansoni. 50 bp DNA ladder (A). Untreated control S. mansoni (B). S. mansoni worms exposed to an LC50 of AL (C). S. mansoni worms exposed to an LC50 of CU (D).

Fig. 3:

Lane profile analysis of S. mansoni DNA fragments. Samples were run alongside a 50 bp DNA ladder (A). Untreated control S. mansoni (B). S. mansoni worms exposed to an LC50 of AL (C). S. mansoni worms exposed to an LC50 of CU (D).