Spermidine, also known as spermidine trihydrochloride, is a polyamine. It is widely distributed in organisms and is biosynthesized by putrescine (butanediamine) and adenosylmethionine.
Spermidine is an abundant natural polyamine found in wheat germ. It can inhibit neuronal synthase, bind and precipitate DNA, and can also be used to purify DNA binding protein, stimulate T4 polynucleotide kinase activity.