Determination of antioxidant activity of tea by HPLC-DPPH

Based on the concept of the activity integrated fingerprint,an on-line HPLC-DPPH system was developed to determine the antioxidant activity of tea.The chromatographic and biological activity fingerprint of tea-scavenging DPPH were simultaneously identified for different brands by HPLC-DPPH.The total antioxidant activities of 11 batches of tea samples were acquired by data analysis,which showed significant differences.The results suggested that the on-line method might reveal the potential information for the identification and quantitation of the active ingredients,which were directly associated with the quality of health foods and herbal medicines.