Ursonic acid belongs to the family of Ursane Triterpenes whose structure is based on the pentacyclic ursane skeleton. It has potential as HIV-1 Protease Inhibitor.

Tyroserleutide TFA, isolated from the degradation products of porcine spleen, is a small molecular tripeptide which inhibits tumor growth both in vitro and in vivo.

Aminoisobutyric acid is a nonprotein amino acid (is an end product of pyrimidine metabolism) excreted in the urine of about 5% of healthy individuals and high excretion is an autosomal recessive phenotype.