2C-O1-1000 PDF
The application of matrix screening-based MALDI-MS technique to the evaluation of food functionality: Metabolic profiling of green tea extracts
Matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) can detect bioactive components from green tea extracts (GTEs), but little is known about its application to the metabolic profiling (MP)-based nuraceutical evaluation of GTEs. Here we performed metabolomic analyses to explore the potential relationship between the composition profile and health-promoting attribute, antioxidant activity, of diverse GTEs. Generally, it is known that there is no perfect MALDI matrix for ionizing all molecules, and ionizable molecular coverage of each matrix is limited. To obtain favorable MALDI matrix for detecting GTE compounds, we performed the matrix screening using more than 50 phytochemicals and 4 major matrices. In negative ionization mode, 1,5-diaminonaphthalene (1,5-DAN) was the best matrix for detecting phytochemicals, and also detected various GTE compounds. Twenty-one GTEs were subjected to 1,5-DAN-MALDI-MS to explore the potential relationship among composition profiles of GTEs. The multivariate analysis showed that composition pattern clearly differed among cultivars or picking seasons. We also succeeded in constructing a reliable bioactivity-prediction model to predict the oxygen radical absorbance capacity (ORAC), antioxidant activity, of GTEs based on their composition profiles. These results suggest that matrix screening-based approach is a promising strategy for MALDI-MS application and 1,5-DAN-MALDI-MS-MP is useful for MP-based evaluation of GTE functionality.