摘要
Ethnopharmacological relevanceAdiantum capillus-veneris L. is a wildly distributed plant species and has been extensively used in south of China as traditional folk medicine for the treatment of inflammatory diseases.Aim of the studyTo investigate the anti-inflammatory effect of ethanolic extracts of Adiantum capillus-veneris L. and the involvement of NF-¦ÊB signaling in the regulation of inflammation.Materials and methodsThe plant ethanolic extracts were initially tested against lipopolysaccharide (LPS)-induced prostaglandin E2 (PGE2) production in RAW264.7 mouse macrophages, and interleukin 6 (IL-6) and tumor necrosis factor (TNF) production in human U937 monocytes. The effect of the plant extracts on the transcription factor nuclear factor kappa B (NF-¦ÊB) pathway was evaluated in TNF-¦Á stimulated HepG2 cells by luciferase gene reporter assay and Western blotting at the transcriptional and translational levels. Subsequently, the inhibition of NF-¦ÊB downstream gene expression (IL-8 and ICAM-1) by the plant extracts was assessed via quantitative real time polymerase chain reaction (qPCR). Lastly, the anti-inflammatory activities of the plant extracts in vivo were evaluated by testing spleen index and NF-¦ÊB related protein expression in LPS-stimulated CD1 mice.ResultsThe plant ethanolic extracts effectively suppressed PGE2, IL-6 and TNF release with an IC50 less than 50 ¦Ìg/ml. Moreover, luciferase expression could be specifically blocked in HepG2 cells, not in HEK293 cells, showing that the plant extracts displayed a cell-specific pattern on NF-¦ÊB gene transcription. The assayed biological activity also depended on the order of adding TNF-¦Á and the plant extracts because the plant extracts could only block the NF-¦ÊB activation if added earlier but were unable to stop the signal when added after TNF-¦Á. However, the plant extracts did not exert any effect on ubiquitination which regulates several steps in the NF-¦ÊB pathway. Additionally, the plant extracts down-regulated phosphorylation of IKK¦Á/¦Â at S176/180, p38 at T180/Y182 and p65 at S536, but not p65 at S276. This was confirmed by their ability to selectively abrogate the induction of IL-8 transcription, whereas the ICAM-1 gene, which is not transcribed selectively by an NF-¦ÊB complex containing a form of p65 phosphorylated on Ser536, did not change. Finally, the plant extracts at 200 ¦Ìg/mg could normalize the LPS-induced elevation of spleen index as well as NF-¦ÊB and p38 activations in CD1 mice.ConclusionThe present studies presents the potential utilization of this plant extracts, as a natural resources for the development of an anti-inflammatory medicine.