Genipin is a chemical compound found in gardenia fruit extract. Genipin is an excellent natural cross-linker for proteins, collagen, gelatin, and chitosan cross-linking. Furthermore, genipin can be used as a regulating agent for drug delivery, as the raw material for gardenia blue pigment preparation, and as the intermediate for alkaloid syntheses. In vitro experiments have shown that genipin blocks the action of the enzyme uncoupling protein 2.