Evaluation of antioxidant and anticancer activities of naphthoquinones-enriched ethanol extracts from the roots of Onosma hookeri Clarke. var. longiforum Duthie

Abstract

In this study, the optimal naphthoquinones-enriched ethanol extract from the roots of Onosma hookeri Clarke. var. longiforum Duthie (OHC-LD) was obtained under an optimal condition (69% ethanol, material to solution ratio of 27:1 at 60℃ for 59 min) by the ultrasound-assisted extraction, according to four-variable three-level Box–Behnken design-response surface methodology. The experimental yield of ethanol extract was 42.08 ± 0.65%, and the contents of naphthoquinones reached to 1.07 ± 0.004%. The optimal extract exhibited similar scavenging activity against ABTS (2,2'-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid) radical as BHT(butylated hydroxytoluene) at 1,250 µg/ml, and better DPPH (2,2-diphenyl-1-picrylhydrazyl) scavenging activity than BHT at 250 µg/ml. However, the optimal ethanol extract was not sensitive to MCF-7 cell line (IC50 of 321.849 µg/ml). The results revealed the naphthoquinones-enriched ethanol extract from the roots of OHC-LD had could be used as a potential natural antioxidant.