Antioxidant and anti-inflammatory activities of water extracts and ethanol extracts from Portulaca oleracea L.

Abstract

Portulaca oleracea L., a species of Portulacaceae, is ubiquitous. It is a well-known traditional Chinese medicine for removing heat, counteracting toxicity, cooling blood, and maintaining hemostasia; it is also used as antidysentery agent. This study investigated the anti-oxidative and anti-inflammatory activities of water and ethanol extracts from P. oleracea. The total polyphenol content (21.08±0.03 mg GAE/g) and total flavonoid content (5.45±0.76 mg QE/g) of the ethanolic extracts were higher than those of the water extracts. The antioxidative activities were determined by evaluating the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activity and by the ferric reducing antioxidant potential (FRAP) assay. The ABTS radical scavenging activity of the water extract (75.53%) was higher in those of the water extract (67.03%) at concentration of 1,000 μg/mL. The DPPH radical scavenging activity and FRAP of the ethanol extract were higher than those of the water extract. We also investigated the anti-inflammatory activity of the P. oleracea extracts in LPS-stimulated Raw 264.7 cells. The production levels of nitric oxide (NO) and reactive oxygen species (ROS) significantly decreased with an increasing concentration of the extract. The expression levels of pro-inflammatory cytokines (tumor necrosis faction (TNF)-α, interleukin (IL)-1β, and IL-6) were significantly lower in the ethanol extract than in the LPS alone treatment group. Based on these results, ethanolic extract from P. oleracea could be an effective antioxidant and anti-inflammatory agent.