In vitro Anti-inflammatory Activity with Ethanolic Leaf Extracts of Rivea hypocrateriformis LPS Stimulated Raw 264.7 Macrophages

Abstract

Aims: To investigate the effect of R. hypocrateriformis extract on the production of proinflammatory cytokines by macrophages. Background: The whole plant was extracted with ethanol at room temperature. The in vitro antiinflammatory activity of RH was investigated on lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Objective: LPS-induced nitric oxide (NO) production was determined by the Griess method. Production of pro-inflammatory cytokines including Interleukin-1 beta (IL-1 β), Interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and cyclooxygenase-2 (COX-2) was examined using reverse transcriptase - polymerase chain reaction (RT-PCR) and Western blot analysis. Under in vitro conditions, RH in doses ranging from 6.25 - 100 μg/mL significantly inhibited lipopolysaccharideinduced nitric oxide production and the production of pro-inflammatory mediators. Methods: In vitro determinations of the toxic effects of unknown compounds have been performed by counting viable cells after staining with a vital dye. Alternative methods used are the measurement of radioisotope incorporation as a measure of DNA synthesis, counting by automated counters, and others that rely on dyes and cellular activity. The MTT system is a means of measuring the activity of living cells via mitochondrial dehydrogenases. The MTT method is simple, accurate, and yields reproducible results. Results: In this study, we investigated whether R. hyocrateriformis can inhibit the production of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) in LPS-activated macrophages. In addition to its pivotal role in many body functions, NO has also been implicated in the pathology of many inflammatory diseases, including arthritis, myocarditis, colitis, and nephritis. Conclusion: R. hypocrateriformis extract suppressed the pro-inflammatory cytokine production in LPS-stimulated RAW264.7 macrophages. Hence, R. hypocrateriformis extract is a potential candidate for the development of pharmacological agents useful in the treatment of inflammatory diseases. Further research on the effects and molecular mechanisms of the active compound in the extract is needed to precisely define thestructure-activity relationship in various molecular regulatory mechanisms.