Inhibitory effect of fulvic acid extracted from Canadian sphagnum peat on chemical mediator release by RBL-2H3 and KU812 cells

Biosci Biotechnol Biochem. 2007 May;71(5):1294-305. doi: 10.1271/bbb.60702. Epub 2007 May 7.


Fulvic acid (FA) was extracted and purified from Canadian Sphagnum peat (CP-FA) and characterized by using an element analysis meter, Fourier transform infrared (FT-IR) spectroscopy, electron spin resonance (ESR) spectroscopy, and (13)C-nuclear magnetic resonance ((13)C-NMR) spectroscopy. To investigate the antiallergic effect of CP-FA, we incubated rat basophilic leukemia (RBL-2H3) cells with 0.001-10.0 microg/ml of CP-FA and determined the beta-hexosaminidase release inhibition at different response stages. The intracellular calcium [Ca(2+)](i) level was also determined by using Fluo 3-AM, a calcium-specific fluorescent probe, and the cytotoxicity of CP-FA was determined by the 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. The results revealed that RBL-2H3 cells incubated for 48 h with 0.001-10.0 microg/ml of CP-FA did not show any decreased viability. CP-FA inhibited the beta-hexosaminidase release by IgE-sensitized, antigen-stimulated RBL-2H3 cells at the antigen-antibody binding stage and the antibody-receptor binding stage. CP-FA also inhibited histamine release from A23187 plus PMA- or compound 48/80-stimulated KU812 cells. Furthermore, there was a decrease in the intracellular [Ca(2+)](i) level in IgE-sensitized cells incubated with CP-FA and stimulated with antigen. Our results show that CP-FA may be useful for the treatment or prevention of allergic diseases.

MeSH terms

  • Animals
  • Anti-Allergic Agents / pharmacology*
  • Antigen-Antibody Complex / immunology
  • Antigens / immunology
  • Basophils / metabolism*
  • Benzopyrans / pharmacology*
  • Calcimycin / pharmacology
  • Calcium / analysis
  • Cell Line, Tumor
  • Dose-Response Relationship, Drug
  • Fluorescent Dyes
  • Formazans / metabolism
  • Histamine Release / drug effects*
  • Humans
  • Immunoglobulin E / pharmacology
  • Ionophores / pharmacology
  • Leukemia, Basophilic, Acute
  • Leukemia, Experimental
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive
  • Nuclear Magnetic Resonance, Biomolecular
  • Plant Extracts / pharmacology*
  • Rats
  • Spectroscopy, Fourier Transform Infrared
  • Sphagnopsida / chemistry*
  • Tetradecanoylphorbol Acetate / pharmacology
  • Tetrazolium Salts / metabolism
  • beta-N-Acetylhexosaminidases / antagonists & inhibitors
  • p-Methoxy-N-methylphenethylamine / pharmacology


  • Anti-Allergic Agents
  • Antigen-Antibody Complex
  • Antigens
  • Benzopyrans
  • Fluorescent Dyes
  • Formazans
  • Ionophores
  • Plant Extracts
  • Tetrazolium Salts
  • MTT formazan
  • Immunoglobulin E
  • Calcimycin
  • p-Methoxy-N-methylphenethylamine
  • beta-N-Acetylhexosaminidases
  • Tetradecanoylphorbol Acetate
  • Calcium
  • fulvic acid