Dermorphin
Dermorphin is a hepta-peptide first isolated from the skin of South American frogs belonging to the genus Phyllomedusa. The peptide is a natural opioid that binds as an agonist with high potency and selectivity to mu Opioid receptors. Dermorphin is about 30–40 times more potent than morphine but theoretically may be less likely to produce drug tolerance and addiction (due to its high potency). The amino acid sequence of dermorphin is H-Tyr-D-Ala-Phe-Gly-Tyr-Pro-Ser-NH2.