Inhibitory effect of selected medicinal plants on the release of pro-inflammatory cytokines in lipopolysaccharide-stimulated human peripheral blood mononuclear cells

The inhibitory activities of the methanol extracts from 20 selected medicinal plants on the release of pro-inflammatory cytokines in human peripheral blood mononuclear cells (PBMCs) were evaluated. The major compound from the most active plant extract was also investigated. The inhibitory effect of the methanol extracts on the release of pro-inflammatory cytokines was tested by incubating PBMCs with the sample and then stimulating by lipopolysaccharide at 0.1 μg/ml. The level of cytokines was determined using enzyme-linked immunosorbent assay. Among the extracts tested, Andrographis paniculata extract demonstrated the strongest inhibition of interleukin (IL)-1β, IL-1α, and IL-6 release, with IC50 values of 1.54, 1.06, and 0.74 μg/ml, respectively. The IC50 value of A. paniculata extract was significantly higher than that of andrographolide on IL-1α, IL-1β, and IL-6 (p