Localization and interaction of hydroxyflavones with lipid bilayer model membranes: A study using DSC and multinuclear NMR

•The interaction of six flavones with DPPC was studied using DSC and NMR.•The distribution of flavones depends on the number and position of hydroxyl group.•Either 6-OH or 5,7-dihydroxy substitution favors greater interaction with DPPC.•Binding to DPPC is due to both hydrophobic and hydrogen bonding interactions.•CHY lies perpendicular whereas 6-HF and BLN are parallel to the bilayer normal.

The localization and interaction of six naturally occurring flavones (FLV, 5HF, 6HF, 7HF, CHY and BLN) in DPPC bilayers were studied using DSC and multi-nuclear NMR. DSC results indicate that FLV and 6HF interact with alkyl chains. The 1H NMR shows interaction of flavones with the sn-glycero region. Ring current induced chemical shifts indicate that 6HF and BLN acquire parallel orientation in bilayers. 2D NOESY spectra indicate partitioning of the B-ring into the alkyl chain region. The DSC, NMR and binding studies indicate that 5HF and 7HF are located near head group region, while 6HF, CHY and BLN are located in the vicinity of sn-glycero region, and FLV is inserted deepest in the membrane.

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