Table 2.

NQO1 activity and ARE induction of licorice and compounds.

Extracts	NQO1 induction CDa ± SD	NQO1 induction Slopeb	NQO1 induction R2b	LC50c	CId	ARE induction Slopeb	ARE induction R2b
GG	8.7 ± 0.62	0.08	0.93	58 ± 3.2	6.6 ± 0.83	0.11	0.59
GU	12 ± 1.9	0.05	0.89	> 60	N/A	0.07	0.83
GI	8.3 ± 0.33	0.13	0.99	37 ± 4.2	4.4 ± 0.66	0.57	0.97
hops	2.9 ± 0.15	0.31	0.96	36 ± 5.1	12 ± 7.9	0.21	0.98
Compounds
LigC	3.5 ± 0.7	0.34	0.98	24 ± 2.0	6.9 ± 1.7	0.37	0.64
LigF	11 ± 0.61	0.05	0.93	> 100	N/A	0.00	0.07
LicA	5.5 ± 0.36	0.18	0.93	24 ± 1.1	4.3 ± 0.50	1.9	0.97
XH	1.5 ± 0.10	0.49	0.97	16 ± 1.0	10.7 ± 1.4	2.0	0.93
curcumin	5.4 ± 0.11	0.19	0.97	18 ± 1.2	3.3 ± 0.29e	0.28	0.91
sulforaphane	0.29 ± 0.06	2.9	0.98	8.1 ±	28 ± 7.5f	2.6	0.99
4'-bromoflavone	0.03 ± 0.002	20	0.93	> 100	> 3000g	N/Ag	N/Ag

^aCD, concentration (μM) doubling the NQO1 activity

^bSlope, the slope of the linear regression analysis line fit

^cLC₅₀, the concentration (μM) leading to 50% of the maximal toxicity

^dCI, chemopreventive index calculated as $\frac{\mathrm{LC}50}{\mathrm{CD}}$

^eConsistent with literature75

^fConsistent with literature

^gN/A, not analyzed