Lipid Peroxidation and Antioxidant Activities of the Aqueous Rhizome Extract of Rheum officinale Baillon

Table 1

Radical scavenging and metal chelating activities of aqueous Rheum extracts.

Concentration of Rheum extract (mg/mL)	DPPH (mg AA/mL)	ABTS (mg TE/mL)	FRAP (mM Fe^2+/mL)	Copper chelating (% of control)
0.25	0.02 ± 0.01^a	0.38 ± 0.01^d	0.02 ± 0.02^c	2.68 ± 4.86^a
0.50	0.05 ± 0.01^b	0.76 ± 0.02^c	0.08 ± 0.03^bc	8.80 ± 4.93^ab
1.00	0.07 ± 0.01^c	0.88 ± 0.01^b	0.13 ± 0.04^b	13.98 ± 3.85^b
2.50	0.11 ± 0.02^d	0.94 ± 0.00^a	0.21 ± 0.01^a	23.61 ± 5.72^c
5.00	0.13 ± 0.02^e	0.94 ± 0.00^a	0.33 ± 0.09^a	45.01 ± 2.88^d

Values are expressed as the mean ± standard deviation (SD) from at least three experiments (). Different letters indicate a significant difference among groups according to Bonferroni procedure (). AA, ascorbic acid; ABTS, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid; DPPH, 2,2-diphenyl-1-picrylhydrazyl); FRAP, ferric reducing antioxidant power; TE, Trolox equivalent.