'Magic blue'--subtle reagent for EPR studies on H-abstraction from various substrates.

This paper is an EPR study on the generation of new 'magic blue' (MB) reagent containing bis{perfluoro[1-(2-fluorosulfonyl)ethoxy]ethyl}nitroxide 2 and perfluoro[1-nitroso-1-(2-fluorosulfonyl)ethoxy]ethane 3, both bearing chemically convertible terminal omega-fluorosulfonyl group -SO2F, and its H-abstraction reactions from arylalkanes, alcohols, aldehydes and polymers, leading to a large number of new fluorinated nitroxides (FN).

The antioxidative function of lutein: electron spin resonance studies and chemical detection.

In the present study, both electron spin resonance (ESR) and chemical detection confirmed that lutein [extracted from alfalfa (Medicago sativa L.)], the most abundant xanthophyll in thylakoids of chloroplasts, could serve as an antioxidant to scavenge reactive oxygen species (ROS) in vitro. Lutein exhibited a greater capacity for scavenging hydroxyl (OH·) and superoxide (O2·-) radicals than ß-carotene at the same concentration, whereas the opposite trend was observed in the capacity for scavenging singlet oxygen (1O2). The capacity of lutein for scavenging ROS from high to low is OH· > O2·- > 1O2. We hypothesise that lutein plays an important photoprotective role in scavenging O2·- and OH· under severe stress. This hypothesis is consistent with our previous report that the lut2 (lutein-deficient) Arabidopsis mutant is more susceptible to damage than the npq1 (lutein-replete but violaxanthin de-epoxidase-deficient) Arabidopsis mutant under severe stress during exposure to high light intensity at low temperature (Peng and Gilmore 2003).