Chemical Components of the Fibrous Root of Ophiopogon japonicus

Abstract

The rhizome of Ophiopogon japonicus is a well-known traditional Chinese medicine that has been employed as an expectorant, anti-cough medicine, and tonic agent [1]. Previous chemical analyses of the rhizomes of O. japonicus have led to the isolation of several components including steroidal saponins [2–6], homoisoflavonoids [7, 8], a cis-eudesmane sesquiterpene glycoside [9], and a spirostan-containing sulfate [10]. In this study, we are not interested in studying the rhizome, but rather its root; indeed, the chemical constituents of the root of this plant are understudied [11]. The present study is a complete investigation of the chemical compositions of the root of O. japonicus. A total of 10 substances were isolated: flavonoids (1–4), sesquiterpenes (5–8), and lignans (9 and 10). Their structures were identified mainly by referencing the published 13C NMR spectral data. The natural lignan 2-(3 -methoxy-4 hydroxybenzyl)-3-(3 -methoxy-4 -hydroxybenzyl)-butyrolactone was isolated for the first time from the fibrous root of Ophiopogon japonicus.