On-line screening and identification of free radical scavenging compounds in Angelica dahurica fermented with Eurotium cristatum using an HPLC-PDA-Triple-TOF-MS/MS-ABTS system.

Eurotium cristatum, a beneficial fungus isolated from Fuzhuan tea, was used to ferment Angelica dahurica for the first time. The antioxidant capacities of the extracts before and after fermentation were compared using ABTS, DPPH and FRAP assays. The results showed that the antioxidant capacities of the extracts acquired using organic solvents were greater after fermentation. Moreover, based on a comparison of the HPLC chromatograms, the chemical composition of Angelica dahurica changed substantially during fermentation. To further understand the changes in its antioxidant constituents, an on-line HPLC-PDA-Triple-TOF-MS/MS-ABTS system was employed. Twelve antioxidants belonging to three different classes were detected and identified, and their antioxidant capacities were preliminarily evaluated. The results indicated that the substances produced during the fermentation of Eurotium cristatum played important roles in enhancing the antioxidant capacity.