Neocarzinostatin chromophore is a naphthoate ester obtained by formal condensation of the carboxy group of 2-hydroxy-7-methoxy-5-methyl-1-naphthoic acid with the 5-hydroxy group of (1aS,5R,6R,6aE,9aR)-5-hydroxy-1a-[(4R)-2-oxo-1,3-dioxolan-4-yl]-2,3,8,9-tetradehydro-1a,5,6,9a-tetrahydrocyclopenta[5,6]cyclonona[1,2-b]oxiren-6-yl 2,6-dideoxy-2-(methylamino)-alpha-D-galactopyranoside. The chromophoric part of neocarzinostatin, it is tightly and non-covelently bound to a 113-membered apoprotein, which serves to protect it and release it to the target DNA. It has a role as an antineoplastic agent.