Bouvardin is a bicyclic hexapeptide isolated from Bouvardia ternifolia. Its chemical formula is C<sub>40</sub>H<sub>48</sub>N<sub>6</sub>O<sub>10</sub>. It is derived from the amino acid sequence Ala-Ala-Tyr-Ala-Tyr-Tyr. It has demonstrated certain anti-cancerous activities by inhibiting protein synthesis through inhibition of 80S ribosomes (eukaryotic ribosomes).