A useful method based on cell-free hemoglobin analysis for evaluating antioxidant activity

Abstract

In the last few decades, a vast array of chemical analytical methods have been proposed and applied for the assessment of antioxidant activities. However, there is no simple standard method by which antioxidant capacity in foods and biological samples can be assessed accurately and quantitatively. In the present study a new approach, based on cell-free hemoglobin (Hb) analysis, is proposed to evaluate antioxidant activity. It is based on the spectrophotometric measurement of Hb concentration at specific wavelength (412 nm). Human Hb was pretreated separately with ginger oleoresin, ginger essential oil, and antioxidant standard molecules (BHT, BHA, quercetin, gallic acid and ascorbic acid). Untreated Hb samples served as controls. Oxidative stress was induced by H₂O₂. Samples were then evaluated by the measurement of Hb. The results showed that ginger oleoresin and essential oil or standard molecules exhibited antioxidant activity in a dose-dependent manner by protecting Hb against its denaturation and degradation, whereas ascorbic acid exhibited a prooxidant effect on Hb. This simple method is easily accessible and provides biologically relevant data and can be proposed as a valuable technique for evaluating the antioxidant activity of vegetable and plant extracts.