As a result of screening for antioxygenic principles in marine algae, the effects of two types of red algae, Polysiphonia urceolata and Gelidium divaricatum, were found to be clearly superior to those of brown algae. Bromophenols with 5-bromo-3, 4-dihydroxy benzaldehyde (I) as the main constituent were identified as the effective principles in P. urceolata. Two types of bromophenols found in P. urceolata, (I) and 5-bromo-3, 4-dihydroxy benzyl alcohol, were synthesized and their antioxidant

more »

... ities compared with several natural and synthetic antioxidants by the following methods: (1) the oven test, (2) oxygen absorption in emulsion, (3) the Active Oxygen Method, (4) the chemiluminescence method. Both of the bromophenols showed considerable antioxidant activity in these tests at low temperature, however, their effects at higher temperatures were poor.