Inhibitory Effect of Fulvic Acid Extracted from Canadian Sphagnum Peat on Chemical Mediator Release by RBL-2H3 and KU812 Cells
Key Findings
- FA extracted from Canadian Sphagnum peat (CP-FA) is not cytotoxic to RBL-2H3 cells at 0.001–10.0 µg/ml after 48h
- CP-FA inhibits β-hexosaminidase release from IgE-sensitized, antigen-stimulated RBL-2H3 cells at antigen-antibody binding stage (p<0.05 at 0.01–10.0 µg/ml)
- CP-FA inhibits β-hexosaminidase release at antibody-receptor binding stage (p<0.05 at 0.01–5.0 µg/ml)
- CP-FA decreases intracellular [Ca²⁺]i level in IgE-sensitized, antigen-stimulated RBL-2H3 cells
- CP-FA dose-dependently inhibits A23187+PMA- and compound 48/80-mediated histamine release from KU812 human basophilic cells at 1.0–10.0 µg/ml
- CP-FA molecular weight 780 Da; structural formula C₃₁H₃₆O₂₂N; purity 99.8%
- CP-FA characterized by FT-IR, ESR, ¹³C-NMR: contains aromatic rings, phenolic hydroxyl, ketone/quinone carbonyl, carboxyl, methoxyl groups
- Canadian Sphagnum peat contains 12.8% HA and 4.8% FA (dry weight)
- Antiallergic mechanism attributed to calcium ion chelating activity and free radical scavenging activity of FA
- FA designated as food by Japanese Ministry of Health and Welfare in June 2005
Rigorous in-vitro study demonstrating the antiallergic properties of fulvic acid extracted from Canadian Sphagnum peat. CP-FA inhibits mast cell degranulation at two stages: antigen-antibody binding and antibody-receptor binding. The mechanism involves decreased intracellular calcium levels and inhibition of histamine release from both rat (RBL-2H3) and human (KU812) basophilic cells. The antiallergic effect is attributed to the chemical composition of FA — aromatic rings with phenolic hydroxyl, quinone carbonyl, and methoxyl functional groups — which shares structural similarities with flavonoid antiallergic compounds like quercetin and luteolin. CP-FA from Sphagnum peat showed stronger antiallergic activity than FA from weathered coal, suggesting peat origin matters.