inhibition of nitric oxide production and proinflammatory cytokines by several medicinal plants

background: a number of medicinal plants have been used to treat various immunological diseases. nitric oxide (no) has an important regulatory role in the various types of inflammatory processes. objective: to investigate the no modulatory activity of the extracts of several medicinal plants native to iran including dracocephalum kotschyi, linum persicum, dionysia termeana, salvia mirzayanii, ferulago angulata and euphorbia cheiradenia. methods: the methanolic extracts of the plants were prepared and examined for their effects on the no production by lipopolysaccharide-stimulated mouse macrophages. the level of tnf-α and il-1β proinflammatory cytokines in the macrophage culture were detected using enzyme-linked immunosorbent assay. results: all the extracts at concentration of 50 μg/ml demonstrated a significant decrease in no production (p