Glycyrrhiza uralensis (Leguminosae) is a well-known herbal medicine that has long been valued as a demulcent to relieve inflammatory disorders. To compare the influence of different solvents on the anti-inflammatory efficacy of G. uralensis, we measured the inhibition of pro-inflammatory mediators such as NO, TNF-α, and PGE2 in lipopolysaccharide (LPS)-stimulated mouse macrophage RAW 264.7 cells by extracts produced using different solvents (water, methanol, ethanol, or n-hexane). The results showed that methanol was the most effective solvent for the inhibition of both NO and PGE2 production in RAW 264.7 cells. However, there was no difference among the extracts for inhibition of TNF-α. Further study must be performed for the analysis of correlation between the anti-inflammatory activity of extracts produced using different solvents and the content of major bioactive compounds in G. uralensis, such as glycyrrhizin and liquiritin. The present study suggests that methanol may be a more appropriate solvent of G. uralensis than other solvents (water, ethanol, and n-hexane) to yield the greatest anti-inflammatory activity for food additives and medicine.

Rhubarb is the well-known and frequently used herbal medicine for the treatment of constipation, inflammation, and cancer. As described in the Korea and Chinese Pharmacopoeia, rhubarb consists of the roots and rhizomes of Rheum palmatum, R. officinale, and R. tanguticum. However, the pharmacological differences among rhubarb have not been scientifically established. In the present study, we investigated and compared the inhibitory effects of 70% ethanolic extracts from R. palmatum (RPE), R. officinale (ROE), R. nobile (RNE), and R. franzenbachii (RFE) on the production of inflammatory mediators, nitric oxide (NO), prostaglandin E2 (PGE2), interlukin-1beta (IL-1β), and tumor necrosis factor-alpha (TNF-α) in RAW 264.7 macrophage cells. ROE, RNE, and RFE significantly inhibited the release of NO, PGE2, IL-1β, and TNF-α. RPE significantly reduced the release of IL-1β, but not NO, PGE2, and TNF-α. Overall, RFE was found to inhibit the release of PGE2 and IL-1β, to a far greater degree than RPE, ROE, and RNE. Our results indicate that RFE possess the strongest anti-inflammatory activity among 4 tested rhubarb.