Antioxidant activities and silymarin content of Silybum marianum using different extraction methods

Abstract

Silymarin in the leaves, roots, and seeds of Silybum marianum (milk thistle) were analyzed by reversed-phase highperformance liquid chromatography and an ultraviolet detector. The content of silymarin and its constituents (taxifolin, silydianin, and silybin) was compared using water and ethanol (EtOH) extracts. Silymarin was only detected in the seeds of the extracts, whereas the silymarin content in the EtOH extract was higher than in the water extract. The antioxidant activity via 1,1-diphenyl-2- picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline- 6-sulfonic acid (ABTS+) radical scavenging activities of milk thistle and its constituents was evaluated. The EtOH extract of seeds, which contained high level of taxifolin and silybin, showed higher radical scavenging activity than other parts of the EtOH extract and water extract. In addition, silymarin and its individual constituents (taxifolin, silydianin, and silybin) showed antioxidant activity as DPPH and ABTS+ radical scavengers. In particular, taxifolin showed a higher radical scavenging activity than other constituents from the seeds. Therefore, it has been suggested that S. marianum and its active constituents could be a useful material for antioxidant-related various diseases.