Sales of multivitamins have been growing rapidly and the concept of natural multivitamin, plant-based multivitamin, or both has been introduced in the market, leading consumers to anticipate additional health benefits from phytochemicals that accompany the vitamins. However, the lack of labeling requirements might lead to fraudulent claims. Therefore, the objective of this study was to develop a strategy to verify identity of plant-based multivitamins. Phytochemical fingerprinting was used to discriminate identities. In addition, multiple bioassays were performed to determine total antioxidant capacity. A statistical computation model was then used to measure contributions of phytochemicals and vitamins to antioxidant activities. Fifteen multivitamins were purchased from the local markets in Seoul, Korea and classified into three groups according to the number of plant ingredients. Pearson correlation analysis among antioxidant capacities, amount phenols, and number of plant ingredients revealed that ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picryhydrazyl (DPPH) assay results had the highest correlation with total phenol content. This suggests that FRAP and DPPH assays are useful for characterizing plant-derived multivitamins. Furthermore, net effect linear regression analysis confirmed that the contribution of phytochemicals to total antioxidant capacities was always relatively higher than that of vitamins. Taken together, the results suggest that phytochemical fingerprinting in combination with multiple bioassays could be used as a strategy to determine whether plant-derived multivitamins could provide additional health benefits beyond their nutritional value.
Keywords: Bioassay; Fingerprinting; Natural claim; Phytochemicals; Plant-based multivitamins.