Isoflavones from the seedpods of Tephrosia vogelii and pyrazoisopongaflavone with anti-inflammatory effects

Phytochemical investigation of Tephrosia vogelii seedpods led to the isolation of twelve compounds: vogelisoflavone A (1), vogelisoflavone B (2), isopongaflavone (3), onogenin, luteolin, 4',7-dihydroxy-3'-methoxyflavanone, trans-p-hydroxycinnamic acid, tephrosin, 2-methoxygliricidol, dehydrorotenone, 6a,12a-dehydro-α-toxicarol and pinoresinol. Compounds 1 and 2 are reported as new natural products. Isopongaflavone (3) was structurally modified using hydrazine to pyrazoisopongaflavone (4). These compounds were characterized based on their NMR and HRESIMS data. Further, four compounds (1-4) were evaluated for their anti-inflammatory effects in lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells (PBMCs). Treatment of the LPS-stimulated PBMCs with the compounds at a concentration of 100 μM suppressed the secretion of interleukin IL-1β interferon-gamma (IFN-γ), granulocyte macrophage-colony stimulating factor (GM-CSF) and tumour necrosis factor-alpha (TNF-α).

Keywords: Anti-inflammatory; Cytokine; Isopongaflavone; Pyrazoisopongaflavone; Tephrosia vogelii; Vogelisoflavone.