Chemiluminescence quenching microarrays for high throughput screening of antioxidants and its application in evaluating herbal extracts and pure compounds.

In this paper, a novel high throughput screening method for antioxidants was described. The screening process was completed on a 5 cm × 5 cm silica gel 60 plate. Luminol was used as the fluorogenic substrate while hydrogen peroxide employed to excite the chemiluminescence. A dark spot was observed due to quenching effect of antioxidant. A linear model of the integral area of the spot as a function of analyte amount was fit by using vitamin C as positive control. Excellent linearity (R = 0.9978) was obtained in the range of 2.31-23.1 μg. The variation coefficients of intra- and inter-chip precisions were below 5% (n = 10) and 10% (n = 6) respectively. The new method was validated by comparing the analysis result of six flavonoids with that from a sequential injection method. The Pearson correlation coefficient was up to 0.98. A set of traditionally used herbal medicines was screened, and Rhei Radix et Rhizoma showed the strongest signal. The major bioactive ingredients were further assigned by flow injection and MS analyses. These results reveal the prospects of the proposed method to supply a promising tool in vitro for high throughput screening and activity evaluation of antioxidants in a fast, low-cost and reliable manner.