Linear free polyamines were characterized in the venom of the spiders Agelenopsis aperta, Hololena curta, and Paracoelotes
birulai by RP-HPLC coupled to mass spectrometry. The several linear polyamines found were tetramine, pentamine, and
hexamine derivatives. Some of these natural products were identified as N-hydroxylated, guanidylated, or acetylated
compounds. In addition, the biosynthetical pathway leading to the formation of acylpolyamines in spider venoms is discussed.