luteolin-7-glucoside and Liver-Neoplasms

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-κB and α-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 α-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-κB 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-κB was also reduced. The most significantly diminished NF-κB 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.

Topics: alpha-Amylases; Apigenin; Cyclooxygenase 2 Inhibitors; Dipsacaceae; Flavonoids; Glucosides; Hep G2 Cells; Humans; Liver Neoplasms; Luteolin; NF-kappa B; Plant Extracts

Luteolin-7-O-glucoside (LUT7G), a flavone subclass of flavonoids, has been found to increase anti-oxidant and anti-inflammatory activity, as well as cytotoxic effects. However, the mechanism of how LUT7G induces apoptosis and regulates cell cycles remains poorly understood. In this study, we examined the effects of LUT7G on the growth inhibition of tumors, cell cycle arrest, induction of ROS generation, and the involved signaling pathway in human hepatocarcinoma HepG2 cells. The proliferation of HepG2 cells was decreased by LUT7G in a dose-dependent manner. The growth inhibition was due primarily to the G2/M phase arrest and ROS generation. Moreover, the phosphorylation of JNK was increased by LUT7G. These results suggest that the anti-proliferative effect of LUT7G on HepG2 is associated with G2/M phase cell cycle arrest by JNK activation.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Caspases; Cell Proliferation; Flavones; G2 Phase Cell Cycle Checkpoints; Glucosides; Hep G2 Cells; Humans; JNK Mitogen-Activated Protein Kinases; Liver Neoplasms; M Phase Cell Cycle Checkpoints; Phosphorylation; Reactive Oxygen Species; Signal Transduction

Eclipta prostrata L., (Asteraceae), is used in China for both food and medicine purposes. This research is concerned with the isolation and purification of phytochemical constituents from the aerial parts of E. prostrata, using gradient solvent fractionation, macroporous resin, silica gel, Sephadex LH-20 and ODS columns, and TLC analyses. Four fractions (water, 30% ethanol, 60% ethanol and 90% ethanol) were obtained. Four compounds, wedelolactone (I), eclalbasaponin I (II), luteolin (III) and luteolin-7-O-glucoside (IV) were purified and their structures were identified by the interpretation of spectroscopic analyses including MS, (1)H and (13)C NMR. Antitumor activities of extracts (total fraction), four fractions and the isolated compounds were assessed using hepatoma cell smmc-7721 as an in vitro assay system. The 30% ethanol fraction and eclalbasaponin I dose-dependently inhibited the proliferation of hepatoma cell smmc-7721 with IC(50) values of 74.2399 and 111.1703 μg/ml, respectively, more strongly compared with 5-fluorouracil positive control group with the IC(50) value of 195.3131 μg/ml. Antitumor activities of other fractions and compounds were lower than positive control. These results suggested that some specific compounds or extracts from E. prostrata are potential sources of natural anti-tumor materials and worthy of further study.

Topics: Animals; Antineoplastic Agents, Phytogenic; Carcinoma, Hepatocellular; Cell Line, Tumor; China; Coumarins; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Eclipta; Flavones; Glucosides; Humans; Liver Neoplasms; Luteolin; Medicine, Chinese Traditional; Molecular Structure; Plant Components, Aerial; Plant Extracts; Plants, Medicinal; Saponins