Characterization and Antioxidative Activities of Rare C50 Carotenoids-Sarcinaxanthin, Sarcinaxanthin Monoglucoside, and Sarcinaxanthin Diglucoside-Obtained from Micrococcus yunnanensis

While screening for antioxidative carotenoids from marine bacteria, we isolated and identified sarcinaxanthin and its glucosylated compounds (sarcinaxanthin monoglucoside and sarcinaxanthin diglucoside) from a moderately halophilic bacterium-Micrococcus yunnanensis strain AOY-1. In the singlet oxygen (O-1(2)) quenching model, the IC50 values of the antioxidative activities of these carotenoids were as follows: sarcinaxanthin, 57 mu M; sarcinaxanthin monoglucoside, 54 mu M; and sarcinaxanthin diglucoside, 74 mu M. In addition, the complete proton nuclear magnetic resonance (H-1 NMR) assignments of sarcinaxanthin monoglucoside pentaacetate and sarcinaxanthin diglucoside octaacetate, and fast atom bombardment mass spectrometry/mass spectrometry (FAB-MS/MS) analyses of sarcinaxanthin and sarcinaxanthin monoglucoside are reported for the first time.