Homoisoflavonoids and the Antioxidant Activity of <i>Ophiopogon japonicus</i> Root.

Abstract

The root of <i>Ophiopogon japonicus</i> has been used as a traditional Chinese medicine and also a functional food ingredient for a long time in China. In the present study, 17 different homoisoflavonoid compounds were identified in the root extract of <i>O. japonicus</i> by HPLC-DAD and LCMS/MS analyses. The antioxidant activity of the of chloroform/methanol (1:1, v/v), methanol and 70% ethanol extracts, and two major isolated homoisoflavonoid compounds (methylophiopogonanone A and methylophiopogonanone B) from <i>O. japonicus</i> root were investigated by various <i>in-vitro</i> assays. Methylophiopogonanone B showed the highest antioxidant ability according to four antioxidant methods. Among the extracts, the chloroform/methanol extract which contained high amounts of homoisoflavonoids was found to exhibit the strongest antioxidant activity. The results showed that <i>O. japonicus</i> root can be regarded as a potential source of homoisoflavonoids and natural antioxidant.