In vitro and in vivo evaluation of antioxidant activity of Petasites japonicus Maxim. flower buds extracts.

The antioxidant activity of Petasites japonicus flower buds cultivated in Tokushima, Japan, was examined in vitro and in vivo. The flower bud extracts were assayed using either oxygen radical absorbance capacity or 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. Antioxidants in the 80% ethanol extract were investigated using online high-performance liquid chromatography-DPPH and were identified as caffeic acid, 3-O-caffeoylquinic acid, fukinolic acid, 3,4-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid, and 4,5-di-O-caffeoylquinic acid using liquid chromatography-mass spectrometry. Fukinolic acid was the most active compound based on its activity and abundance. Administering the extracts orally to ICR mice prior to iron injection significantly suppressed plasma thiobarbituric acid reactive substance (TBARS) production. Moreover, TBARS and triglyceride concentrations in the plasma of C57BL/6 mice fed with a high fat diet were also significantly decreased by the extract. The results suggest that antioxidative compounds in P. japonicus can be used in the management of oxidative stress.