Shikonin, a natural naphthoquinone, has attracted much attention due to its various biological activities. Two shikonin glucosides, shikonin-1',8-di-O-β-D-glucopyranoside (1) and shikonin-1'-O-β-D-glucopyranoside (2), were biosynthesized through in vitro enzymatic glycosylation and their structures were elucidated using spectroscopic techniques. The water-solubility and stability of compounds 1 and 2 were significantly higher than those of the parent compound. Furthermore, compound 2 showed moderate cytotoxicity against six cancer cell lines, with IC50 values ranging from 36.10 to 67.47 µM. This research indicated that in vitro enzymatic glycosylation of shikonin is an effective strategy to improve it water solubility and chemical stability.
Keywords: cytotoxicity; enzymatic glycosylation; shikonin; stability; water-solubility.