Ethanol extract of propolis inhibits nitric oxide synthase gene expression and enzyme activity.
Propolis obtained from honeybee hives has been used in Oriental folk medicine as an anti-inflammatory, anti-carcinogenic, or immunomodulatory agent. However, the molecular basis for anti-inflammatory properties of propolis has not yet been established. Since nitric oxide (NO) synthesized by inducible nitric oxide synthase (iNOS) has been known to be involved in inflammatory and autoimmune-mediated tissue destruction, modulation of NO synthesis or action represents a new approach to the treatment of inflammatory and autoimmune diseases. The present study, therefore, examined effects of ethanol extract of propolis (EEP) on iNOS expression and activity of iNOS enzyme itself. Treatment of RAW 264.7 cells with EEP significantly inhibited NO production and iNOS protein expression induced by lipopolysaccharide (LPS) plus interferon-gamma (IFN-gamma). EEP also inhibited iNOS mRNA expression and nuclear factor-kappa B (NF-kappaB) binding activity in a concentration-dependent manner. Furthermore, transfection of RAW 264.7 cells with iNOS promoter linked to a chloramphenicol acetyltransferase (CAT) reporter gene, revealed that EEP inhibited the iNOS promoter activity induced by LPS plus IFN-gamma through the NF-kappaB sites of the iNOS promoter. In addition, EEP directly interfered with the catalytic activity of murine recombinant iNOS enzyme. These results suggest that EEP may exert its anti-inflammatory effect by inhibiting the iNOS gene expression via action on the NF-kappaB sites in the iNOS promoter and by directly inhibiting the catalytic activity of iNOS.
Song
Yun Seon
YS
Bioanalysis and Biotransformation Research Center, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 130-650, South Korea.
Park
Eun-Hee
EH
Hur
Gang Min
GM
Ryu
Young Sue
YS
Kim
Yong Man
YM
Jin
Changbae
C
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D001665:Binding Sites; D002460:Cell Line; D024202:Electrophoretic Mobility Shift Assay; D000431:Ethanol; D007371:Interferon-gamma / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000201:enzymology; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D010936:Plant Extracts / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D011429:Propolis / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012997:Solvents
D000893:Anti-Inflammatory Agents; D008070:Lipopolysaccharides; D016328:NF-kappa B; D010936:Plant Extracts; D012997:Solvents; D000431:Ethanol; D007371:Interferon-gamma; D011429:Propolis; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse