salinomycin

Salinomycin is a polyether antibiotic and potassium ionophore produced by certain strains of Streptomyces, most notably Streptomyces albus. It is used primarily in veterinary medicine as a coccidiostat and growth-promoting additive in poultry diets, and is approved or allowed in various regions for prophylaxis against coccidiosis and nematode infections in ruminants. It is not approved for human therapeutic use in most jurisdictions.

Mechanism of action: Salinomycin acts as a monovalent cation ionophore that shuttles potassium ions across lipid membranes. By dissipating ion gradients and disrupting electrochemical potential, it impairs cellular energy production and ion homeostasis. Its selectivity toward Gram-positive organisms stems from the outer membrane barrier present in many Gram-negative bacteria.

Clinical and research applications: In veterinary settings, salinomycin reduces intestinal parasite burdens and supports weight gain in poultry. In medical research, it has attracted attention for its reported ability to selectively target cancer stem cells and reduce tumor growth in several models. However, despite numerous preclinical findings, it is not approved as a cancer therapy and concerns about safety, dosing, off-target effects, and species differences limit clinical development.

Safety and regulation: Salinomycin can be toxic to non-target species at higher exposures, with potential effects on muscle, nerve, and cardiac tissues. Handling requires appropriate protective equipment, and withdrawal times are observed to avoid residues in animal products intended for human consumption. Regulatory status varies by country and product formulation.