Department of Environmental Toxicology, University of California, Davis, California, USA
Research Article
Antioxidant Activity of Rhubarb (Rheum rhabarbarum L.) Extract and Its Main Component Emodin
Author(s): Hae Won Jang, Wan-Hsuan Hsu, Matt J Hengel and Takayuki Shibamoto*
Freeze-dried rhubarb was fractionated using column chromatography with organic solvents (various ratios of water/methanol and acetone). The seven fractions obtained were examined for antioxidant activity using a gas chromatography/malonaldehyde (GC/MA) assay. Emodin (6-methyl-1,3,8-trihydroxyanthraquinone) in each fraction was analyzed by HPLC with a diode array detector. The amounts of emodin found in the seven fractions ranged from 22.4 ± 0.35 μg/g of dried rhubarb (100% methanol eluate) to 0.33 ± 0.01 μg/g (acetone eluate). Emodin was not detected in the fractions eluted with water/methanol mixtures. Among the seven fractions, the fraction eluted with 100% methanol showed the greatest antioxidant activity and contained the highest level of emodin. This fraction exhibited antioxidant activities by 75.4 ± 13.7% at the level of 50 μg/mL, 92.8 ± 0.6.. View More»
DOI:
10.35248/2329-891X.18.6.316
