Wound-healing activity of an oligomer of alkannin/shikonin, isolated from root bark of Onosma echioides.

Root bark of Onosma echioides belonging to the family Boraginaceae is reported to be rich in naphthaquinones such as alkannins and shikonins. In this study, a dimer of alkannin/shikonin was isolated from the petroleum ether (60-80 C) extract of the bark, and the structure of the same was elucidated through spectral studies (UV, IR, NMR, MS and DEPT). The petroleum ether extract was found to contain 62.