The effect of luteolin 7-glucoside, apigenin 7-glucoside and Succisa pratensis extracts on NF-κB activation and α-amylase activity in HepG2 cells

The chemical composition of Succisa pratensis is not well known. The existing data indicate a substantial content of flavonoids, which include luteolin and apigenin 7-glucosides. The aim of this study was to elaborate the isolation protocol of these flavonoids from flowers and leaves of S. pratensis, to carry out their characterization, as well as evaluate the effect of S. pratensis extracts on activation of transcription factor NF-kappa B and alpha-amylase activity. The extraction protocol applied in this study allowed isolation and characterization of flavonoid fraction of S. pratensis. Their identity was confirmed by NMR spectra analysis, UV spectroscopy and electrospray ionization-tandem MS evaluation. Treatment of pancreatic alpha-amylase with S. pratensis extract inhibited this enzyme's activity to an extent comparable to that of isolated luteolin and apigenin 7-glucosides. Incubation of HepG2 cells for 24 h with S. pratensis extracts or isolated flavonoids resulted in moderate reduction in NF-kappa B transcription factor activation evaluated in terms of translocation of its active subunits from cytosol into nucleus and subsequently diminished expression of the COX-2 gene. Expression of NF-kappa B was also reduced. The most significantly diminished NF-kappa B activation and expression, as well as COX-2 expression, was found to result from treatment with isolated flavonoids and ethyl acetate extract of S. pratensis leaves. These results indicate that S. pratensis flavonoids may modulate the metabolic and signaling pathways whose deregulation is related to pathogenesis of liver cancer. Further studies are required to confirm these observations and assess the chemopreventive and/or therapeutic potential of the S. pratensis herb.