Effects of phenylethanoid glycosides from Digitalis purpurea L. on the expression of inducible nitric oxide synthase.
We have isolated four different phenylethanoid glycosides (purpureaside A, desrhamnosyl acteoside, calceolarioside B and plantainoside D) from the leaves of Digitalis purpurea (foxglove). The effects of these glycosides on activator protein-1 (AP-1)-mediated inducible nitric oxide synthase (iNOS) gene expression in the Raw264.7 macrophage cell line have been studied. Of these four glycosides, purpureaside A potently inhibited iNOS induction by lipopolysaccharide (LPS). Increase in iNOS mRNA by LPS was completely suppressed by purpureaside A. Purpureaside A did not significantly affect LPS-inducible nuclear factor-kappaB (NF-kappaB) activation or the nuclear translocation of p65. Moreover, a reporter gene assay using AP-1 specific luciferase reporter revealed that the enhanced activity of AP-1 by LPS was completely abolished in cells treated with purpureaside A. These results demonstrated that purpureaside A inhibited LPS-inducible iNOS expression in macrophages through the suppression of AP-1, but not of NF-kappaB.
Oh
Jae Wook
JW
Research Center for Resistant Cells and Department of Anatomy, College of Medicine, Chosun University, Dong-gu, Gwangju 501-759, South Korea.
Lee
Jeong Yong
JY
Han
Song Hee
SH
Moon
Young Hee
YH
Kim
Yoon Gyoon
YG
Woo
Eun-Rhan
ER
Kang
Keon Wook
KW
D002460:Cell Line; D004070:Digitalis / Q000737:chemistry*; D005786:Gene Expression Regulation / Q000187:drug effects; D017930:Genes, Reporter; D006027:Glycosides / Q000494:pharmacology*; D006801:Humans; D008264:Macrophages / Q000201:enzymology; D019001:Nitric Oxide Synthase / Q000096:biosynthesis* / Q000235:genetics; D052247:Nitric Oxide Synthase Type II; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D018808:Transcription Factor AP-1 / Q000502:physiology
D006027:Glycosides; D010936:Plant Extracts; D018808:Transcription Factor AP-1; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II