Sustainable Production and In Vitro Giardicidal Activity of Bioactive Compounds Derived from Arthrospira Platensis

Giardiasis remains a globally prevalent neglected parasitic disease, and limitations associated with conventional therapies highlight the need for alternative and complementary strategies. In this context, microalgae biocompounds have emerged as promising sources of antiparasitic agents.

This study aims to evaluate the in vitro preliminary screening activity (vital dye exclusion).

Aqueous extracts of Arthrospira platensis obtained by different extraction methods, as well as the bioactivity of the product derived from in vitro digestion (PDV), aiming to assess the influence of extraction and digestive bioactivation on antiparasitic efficacy. Extracts were produced by magnetic stirring and sonication, followed by exposure of Giardia duodenalis cysts to increasing concentrations, with metronidazole used as a reference drug. The PDV was generated using a standardized simulated gastrointestinal digestion model. Sonicated extracts showed enhanced membrane damage compared to mechanically stirred extracts, consistent with improved release of intracellular bioactive compounds. The IC₅₀ values for the sonicated, agitated, and PDV samples were, respectively: 95,4; 153.1 and 43.6 μg/mL.

The PDV demonstrated activity across multiple concentrations and, under comparable conditions, outperformed metronidazole. These findings suggest that digestive processing may increase the bioaccessibility of active moieties responsible for antiparasitic effects.

Overall, the results support A. platensis as a sustainable source of giardicidal biocompounds and highlight the relevance of physiologically relevant in vitro digestion models for predicting functional antiparasitic activity and guiding future translational research.