A. Osawa, Y. Kaseya, N. Koue, J. Schrader, C. Knief, J. A. Vorholt, G. Sandmann, K. Shindo
During the course of screening for antioxidative carotenoids from bacteria, we isolated two novel C30 carotenoids, 4-[2-O-11Z-octadecenoyl-β-glucopyranosyl]-4,4′-diapolycopene-4,4′-dioic acid (1) and 4-[2-O-9Z-hexadecenoyl-β-glucopyranosyl]-4,4′-diapolycopene-4,4′-dioic acid (2), from Methylobacterium strains. These compounds possessed the common structure ‘β-d-glucosyl 4,4′-diapolycopene-4,4′-dioic acid’, while the fatty acid attached at the C-2 position of glucose differed. In the singlet oxygen (1O2) quenching model, both 1 and 2 exhibited potent antioxidative activities (IC50: 3.2 and 3.6 μM, respectively).