Protective effects of bacterial glyceroglycolipid M874B against cell death caused by exposure to heat and hydrogen peroxide.

It was revealed by bioassay using sodA and katA mutants of Bacillus subtilis that the bacterial monogalactosyldiacylglycerol M874B, previously characterized as an alkyl peroxyl radical scavenger, was also capable of protecting cells from death caused by heating and exogenous H2O2. Chemical assays using the Fenton reaction and xanthine-xanthine oxidase revealed that M874B could quench hydroxyl radicals but not superoxide anions. Wheat monogalactosyldiacylglycerol, but neither digalactosyldiacylglycerol nor synthetic diacylglycerol, also had the same activities as those of M874B, although it was less efficient than M874B. These results suggest that monogalactosyldiacylglycerols such as M874B are a new type of oxygen radical scavengers capable of quenching some reactive oxygen species.