Chemical fingerprinting, quantification, and antioxidant activity evaluation of <i>Osmanthus fragrans</i> (Thunb.) Lour. Flowers by UPLC-ECD

Osmanthus fragrans (Thunb.) Lour. flowers are important natural resource of phenolic compounds, which have antioxidant activities and have been consumed as functional food and dietary supplements for thousand years. Ultra-performance liquid chromatography coupled with electrochemical detection (UPLC-ECD) was developed to simultaneously analyze the eight phenolic compounds in Osmanthus fragrans flowers collected from different regions across China. The UPLC-ECD fingerprint was established for identification and comprehensive quality control. The antioxidant capacities of Osmanthus fragrans flowers were evaluated, and results were compared with those spectrophotometric antioxidant methods. A highly positive relationship was confirmed between the total peak area of characteristic components in chromatogram and the antioxidant potential determined by spectrophotometry with correlation coefficient greater than 0.80 (p < .01). Grey relational analysis showed that acteoside had the highest degree of correlation with antioxidant capacity. These results provided evidence to support the use of UPLC-ECD as a simple, rapid, and reliable method for electroactive phenolic component determination and antioxidant capacity quantification in vitro system.