Bixin is a carotenoic acid that is the 6'-monomethyl ester of 9'-cis-6,6'-diapocarotene-6,6'-dioic acid. It has a role as an antioxidant, a biological pigment, an insulin-sensitizing drug, an anti-inflammatory agent, an apoptosis inducer and a food colouring. It is a methyl ester, a carotenoic acid and a dicarboxylic acid monoester.