Molluscicidal activity and biochemical effects of the diuretic drug furosemide compared with metaldehyde against the glassy clover snail, Monacha obstructa

Background High-ceiling diuretics such as furosemide (Lasix) promote water and electrolyte excretion by inhibiting sodium and chloride reabsorption in the kidneys, leading to osmotic and ionic imbalance. Accordingly, its potent diuretic action may induce osmotic stress in water-regulating organisms such as terrestrial snails. The molluscicidal activity of furosemide was evaluated against the glassy clover snail, Monacha obstructa , under laboratory conditions and compared with that of metaldehyde as a conventional molluscicide. Treatments were applied using bait method for 72 h. To investigate the mode of action of both treatments, the activities of Alkaline Phosphatase (ALP) and Acid Phosphatase (ACP) enzymes were assessed. Results Our findings established significant differences in the toxicological efficacy of furosemide and metaldehyde against the target land snail. Metaldehyde showed higher toxicity, with LC 50 and LC 90 values of 1.98 and 3.69%, respectively, compared to 9.06 and 13.62% for furosemide. The estimated Relative Toxicity Index (RTI) value showed that metaldehyde was approximately 4.6 times more toxic than furosemide against M. obstructa , demonstrating its superior molluscicidal activity. Biochemical analyses revealed that ACP activity was not significantly affected by both treatments, whereas ALP activity responded markedly to exposure. Metaldehyde induced a pronounced increase in ALP activity, while furosemide caused a slight reduction relative to the control, indicating differential physiological responses to the tested compounds. Conclusions The obtained data provide the first evidence that the loop diuretic furosemide exerts measurable molluscicidal activity against M. obstructa and induces biochemical responses, although it was less effective than metaldehyde. The differential response of ALP and ACP further highlights the value of ALP as a sensitive biomarker of toxic stress and supports the potential of drug repurposing as a promising approach for terrestrial snail management.