ChEBI: Spermidine is a triamine that is the 1,5,10-triaza derivative of decane. It has a role as a fundamental metabolite. It is a triamine and a polyazaalkane. It is a conjugate base of a spermidine(3+).NCI Thesaurus (NCIt): Spermidine is a polyamine derived from putrescine that is involved in many biological processes, including the regulation of membrane potential, the inhibition of nitric oxide synthase (NOS) and the induction of autophagy.