Effects of brewing process on phenolic compounds and antioxidant activity of herbs

Traditionally used medicinal plants contain a wide range of polyphenolic compounds that act as powerful antioxidants. The content of phenolic compounds in the infusions and decoctions of chamomile (Matricaria chamomilla L.) and St. John's wort (Hypericum perforatum), which are traditionally used medicinal herbs, was evaluated via liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. To obtain relevant antioxidant/reducing capacity of the prepared extracts, cupric reducing antioxidant capacity and Folin-Ciocalteu assay were applied. Rutin and apigenin were the major flavonoids in the aqueous extract of chamomile, whereas the predominant phenolic compounds of St. John's wort water extracts were rutin and catechin followed by chlorogenic acid. A longer time of infusion and decoction of St. John's wort herb significantly affected the rutin content. The increase of extraction time had very little impact on the antioxidant activities for chamomile but considerably higher impact on those for St. John's wort.