Isolation and Identification of 4, 4′-Diapolycopene-4,4′-dioic Acid Produced by Bacillus firmus GB1 and its Singlet Oxygen Quenching Activity

We succeeded in purifying the carotenoid produced by Bacillus firmus GB1 using chromatography on polystyrenic synthetic adsorbents, and identified it as 4,4'-diapolycopene-4,4'-dioic acid by HRESI-MS and NMR analyses of it and its dimethylester. In addition, we clarified the singlet oxygen (O-1(2)) quenching activities of 4,4'-diapolycopene-4,4'-dioic acid and its methyl esters (mono and dimethyl ester). Their IC50 values were 5.8 mu M, 6.0 mu M, and 6.2 mu M, respectively. To our knowledge, this is the first report concerning the isolation and antioxidative activity of 4,4'-diapolycopene-4,4'-dioic acid, a product of the C30 carotenoid biosynthesis pathway.