Quantification of the overall reactive oxygen species scavenging capacity of biological fluids and tissues

A method has been developed for measuring and evaluating the overall antiox idant activity derived from the low-molecular weight antioxidants (scavenge rs). The principle governing this method is based on a common chemical char acteristic of the scavengers, their reducing properties. It was hypothesize d and then demonstrated that an evaluation of the overall reducing power of a biological sample correlates with the overall scavenging activity of the sample. In order to quantify the total reducing power, the cyclic voltamme try methodology was applied. The resulting measurements correlated with the antioxidant activity of both hydrophilic and lipophilic scavengers. The me thod is suitable for use in biological fluids and in tissue homogenates, an d can supply information concerning the type of antioxidants and their tota l concentration without having to determine specific compounds. A noninvasi ve procedure for determining skin overall scavenging activity is also descr ibed. This method is based on a well containing an extraction solution that is attached to the skin's surface. Following incubation time the extractio n solution is analyzed using the cyclic voltammeter instrument and other me thods. We have found these methods suitable for evaluating the reducing cap acity status in various clinical conditions such as diabetes, ionizing and nonionizing irradiation, brain degenerative diseases, head trauma, and infl ammatory bowel diseases. This method is also an efficient tool for evaluati ng the overall antioxidant capacity of mixtures of antioxidant preparations in vitro. The measurements themselves are simple and rapid. Furthermore, t hey do not require manipulation of the samples. (C) 2000 Elsevier Science I nc.