Spermine-15N2 (NSC 268508-15N2) is the 15N-labeled version of Spermine. This compound acts as a natural antioxidant and anti-inflammatory agent. Spermine is effective in inhibiting certain bacterial cultures, particularly strains of Staphylococcus aureus, and induces dose-dependent neurotoxicity in the striatum. It can reversibly inhibit DNA synthesis reactions, mixed lymphocyte reactions, and cytotoxic lymphocyte responses in primary cultures of mouse splenocytes. As a polyamine nitric oxide donor, Spermine tetrahydrochloride supplies nitric oxide to platelets and inhibits platelet activation in a concentration-dependent manner. This compound is present in mammalian tissues, plants, bacteria, ribosomes, and bacteriophages, and it can inhibit primary human embryonic lung fibroblast cells in vitro.