Potential application of plant lipid transfer proteins for drug delivery

Ligand-binding proteins show an increasing interest as drug carriers and delivery systems [Wolf FA, Brett GM. Pharmacol Rev, 1000;52:207-36]. The wide binding properties of plant non-specific lipid transfer proteins such as LTP1 also offer many unexplored possibilities for such a task. In the present paper, by using intrinsic tyrosine LTP1 fluorescence, we survey, for the first time, the binding of wheat LTP1 with various ligands having cosmetic or pharmaceutical applications. LTP1 was found to bind skin lipids such as sphingosine, sphingomyelin, and cerebroside with an affinity of about one micromolar, low enough to allow a slow release of these molecules. Ether phospholipids and an azole derivative BD56 having antitumoral and/or antileishmania properties were also shown to bind LTP1 with similar affinity. Finally, amphotericin B, which is widely used as an antifungal drug, was shown to form a complex with LTP1, although no affinity could be determined. This binding study is a prerequisite for further work aimed at developing applications in LTP-mediated transport and controlled release of low molecular weight drugs.