Beta-Hydroxyisovalerylshikonin is an inhibitor of protein-tyrosine kinases such as v-Src and EGFR, and has been shown to induce apoptosis in several human tumor cell lines. Beta-Hydroxyisovalerylshikonin significantly decreased viability of HCT116 cells (IC50 values = 30.9 μg/mL).

By using different chromatographic techniques and appropriate spectroscopic methods, the seven naphthoquinones were described: deoxyshikonin ( 1 ), isobutyrylshikonin ( 2 ), α±-methylbutyrylshikonin ( 3 ), acetylshikonin ( 4 ), Beta-Hydroxyisovalerylshikonin( 5 ), 5,8-O-dimethyl isobutyrylshikonin ( 6 ) and 5,8-O-dimethyl deoxyshikonin ( 7 ). Among the tested compounds, 3 and 4 exhibited the highest antibacterial activities toward all tested bacterial species (MIC50 and MIC90 for gram positive bacteria: 6.40 μg/mL-12.79 μg/mL and 6.82 μg/mL-13.60 μg/mL, respectively; for gram negative bacteria: 4.27 μg/mL-8.53 μg/mL and 4.77 μg/mL-9.54 μg/mL, respectively). Also, naphthoquinones 3 and 4 exhibited strong cytotoxic activity against MDA-MB-231 cells (IC50 values 86.0 μg/mL and 80.2 μg/mL, respectively), while compounds 1 , 3 , 4 and 5 significantly decreased viability of HCT116 cells (IC50 values of 97.8 μg/mL, 15.2 μg/mL, 24.6 μg/mL and 30.9 μg/mL, respectively)[1]