. 2018 Dec 20;24(1):3. doi: 10.3390/molecules24010003

Table 1.

IC₅₀ values (μM) of echinatin and licochalcone A from the four sets of antioxidant colorimetric measurements.

Measurement	Echinatin	Licochalcone A	Trolox
Fe³⁺-reduction	338.0 ± 8.6 ^c	133.2 ± 0.9 ^b	87.5 ± 3.4 ^a
Cu²⁺-reduction	228.1 ± 10.6 ^c	129.1 ± 2.1 ^b	67.5 ± 0.9 ^a
PTIO•-scavenging	1276.5 ± 149.9 ^c	617.4 ± 22.9 ^b	270.9 ± 10.8 ^a
DPPH•-scavenging	394.2 ± 67.5 ^c	102.3 ± 3.6 ^b	47.8 ± 2.6 ^a

The IC₅₀ value was defined as the final concentration of 50% radical inhibition or relative reduction power, calculated using linear regression analysis, and expressed as the mean ± standard deviation (SD) (n = 3). The linear regression was analyzed using the Origin Professional software (2017 version). IC₅₀ values in the same row with different superscripts (^a, ^b, or ^c) were significantly different (p < 0.05). Trolox was the positive control. The dose-response curves are shown in Supplementary File 3.