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IN VITRO MODEL FOR TOTAL ANTIOXIDANT ACTIVITY EVALUATION WITH APPLICATIONS ON BIOLOGICAL PRODUCTS

ALINA MONICA MIFTODE¹, ALINA ŞTEFANACHE^1*, ADRIAN ŞPAC², VASILE DORNEANU³

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In the present paper we are proposing an in vitro model for assessing the overall antioxidant activity by using the radical cation chromophore of chlorpromazine (CP•+) which presents a maximum absorption at 525 nm. A decrease in the radical colour is caused by the presence of antioxidants, proportional to the concentration of antioxidant. For evaluating the antioxidant action, the percentage inhibition of absorbance is being calculated for two established time moments (10 and 20 min), then the kinetic graph is drawn (percentage inhibition as a function of the time), and the area under curve (AUC) is calculated. From the calibration curve, found under similar conditions, (the AUC as a function of the standard antioxidant concentration - gallic acid) one may determine the total antioxidant activity expressed in gallic acid equivalents (GAE). The calibration curve was plotted on two concentrations intervals: 10-50 μM/L and 50-100 μM/L of gallic acid. The method we are proposing involves both the concentration of the antioxidant as well as the time of reaction, constituting a thorough measure of the antioxidant’s ability to scavenge free radicals, related to a standard antioxidant, at selected time points of the reaction. The model may be applied on determining the antioxidant action of complex composition biological products.