. 2014 Aug 5;55(2):90–96. doi: 10.3164/jcbn.13-107

Table 1.

Review of the ROS-scavenging activity of shikonin

ROS	IC₅₀ (µM)	Assay	Reference
O₂^•−	7.2	EPR^†	Sekine et al. (ref. 10)
	17	EPR^†	Gao et al. (ref. 12)
^•OH	40^§	EPR^†	Sekine et al. (ref. 11)
	108	EPR^†	ref. 12
BuOO^•	27	EPR^‡	ref. 12
	113	EPR^†	ref. 12

The sources of superoxide (O₂^•−), hydroxyl radical (^•OH), singlet oxygen (¹O₂) and tert-butyl peroxyl radical (BuOO^•) were respectively, hypoxanthine/xanthine oxidase system, Fenton reaction, hematoporphyrin irradiated with UVB, and tert-butyl hydroperoxide reacting with methemoglobin and diethylenetriamine-N,N,N',N'',N''-pentaacetic acid. ^†spin trap: 5,5-dimethyl-1-pyrroline-N-oxide; ^‡spin trap: 2,2,6,6-tetramethyl-4-piperidone hydrochloride; ^§determined for shikonin and alkannin in mixture (82:18).