. 2013 May 10;18(5):5389–5404. doi: 10.3390/molecules18055389

Table 1.

Antioxidant capacity of curcumin and its structural analogs.

Compound	Antioxidant Capacity *
Compound	DPPH (IC₅₀) (mM)	FRAP (mmole TE/L)	ORAC (mmole TE/L)
Curcumin	0.86 ^e	5.01 ± 0.1 ^c	1.89 ± 0.2 ^a
2a	2.86 ^h	1.13 ± 0.4 ^g	0.12 ± 0.01 ^g
2b	2.58 ^g	3.02 ± 0.02 ^d	0.43 ± 0.1 ^f
2c	4.07 ⁱ	1.32 ± 0.001 ^f	0.11 ± 0.01 ^g
2d	0.72 ^d	5.35 ± 0.1 ^b	0.50 ± 0.02 ^ef
2e	2.57 ^g	0.47 ± 0.1 ^k	0.60 ± 0.1^e
2f	0.71 ^d	1.28 ± 0.04 ^fg	0.49 ± 0.1 ^ef
2g	1.36 ^f	1.12 ± 0.02 ^g	0.84 ± 0.01 ^d
3a	0.07 ^a	1.41 ± 0.1 ^f	1.12 ± 0.1 ^c
3b	0.06 ^a	2.29 ± 0.1 ^e	0.49 ± 0.1 ^ef
3c	0.34 ^c	1.09 ± 0.1 ^gh	1.17 ± 0.1 ^b
3d	0.07 ^a	6.70 ± 0.32 ^a	0.75 ± 0.05 ^d
3e	0.03 ^a	0.67 ± 0.02 ^j	0.69 ± 0.1 ^e
3f	0.09 ^a	1.09 ± 0.1 ^gh	1.30 ± 0.02 ^b
3g	0.51 ^b	0.95 ± 0.02 ^hi	1.25 ± 0.04 ^bc
3h	0.36 ^c	1.05 ± 0.01 ^ghi	0.84 ± 0.1 ^d

* Data are presented as mean ± SD. Mean with different subscripts in each column is significantly different (p < 0.05). FRAP, ferric reducing ability of plasma: used 10 μM compounds dissolved in DMSO. ORAC: oxygen radical absorbance capacity: used 1 μM compounds dissolved in DMSO. TE, Trolox equivalence.