Antitumor activity of shikonin and its derivatives.

Abstract

Shikonin, a naphthoquinone contained in the root of Lithospermum officinalis var. erythrorhizon and Macrotomia euchroma (Boraginaceae), showed a high antitumor activity against the ascites cells [mouse] of sarcoma 180 [in mice]. Shikonin completely inhibited the tumor growth at a dose of 5-10 (mg/kg per day). At a higher dose (> 15 mg/kg per day) shikonin showed toxicity, whereas at a lower dose (1 mg/kg per day) it was inactive. Four shikonin derivatives and the chromatographic fractions of the plant extracts were also tested and they showed similar antitumor activities against S-180.