We tested the antioxidant properties of both aqueous and methanolic extracts of oregano (origanum vulgare) They proved to be effective in the inhibition of all phases of the peroxidative process: first neutralizing free radicals (superoxide anion, hydroxyl radical and 1,1‐diphenyl‐2‐picrylhydrazyl radical), then blocking peroxidation catalysis by iron (through iron‐chelating and iron‐oxidizing properties), and finally through interruption of lipid‐radical chain reactions (chain‐breaking activity). Their anti‐glycosylation activity was also effective. The glycosylation oflipoproteins is directly related to their peroxidation. The amount of extract used in our experiments was obtained from 0.1–1 mg of dried leaves, amounts far less than those normally used in the Mediterranean diet.

Athletes undergoing regular and adequate training show improved antioxidant status together with a more fluid membrane status, which could contribute to improving both peripheral resistance to insulin and all the functional metabolic interchanges in the cellular membrane.

Young, adult, and old rats were used to study the effect of age on the integrity and functioning of brain synaptosomes. An evaluation was made of the differences in lipid composition, membrane fluidity, Na+, K(+)-ATPase activity, and susceptibility to in vitro lipid peroxidation. There was an age-related increase in synaptosomal free fatty acids, with no modification in acyl chain composition, and a decrease in membrane phospholipids which increased the cholesterol/phospholipid mole ratio. With altered lipid composition, there was a corresponding age-dependent decrease in membrane fluidity, a reduction of Na+, K(+)-ATPase activity, and an overall greater susceptibility to in vitro lipid peroxidation. Furthermore, lipid peroxidation promoted strong modifications of the membrane fluidity, lipid composition, and Na+,K(+)-ATPase activity just as aging did, thus indicating a possible contribution of oxidative damage to ageing processes. The cases studied revealed that the greater responsiveness of old membranes to in vitro lipid peroxidation resulted in the highest degree of membrane alteration, indicating that all pathological states known to promote a peroxidative injury can have even more dramatic consequences when they take place in old brain.

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