Anisodamine induces the hexagonal phase in phospholipid liposomes

Area of Science:

• Lipid polymorphism
• Membrane biophysics
• Drug-membrane interactions

Background:

• Cardiolipin and dioleoylphosphatidylcholine are key membrane lipids.
• Lipid phase behavior is crucial for membrane function.
• Anisodamine is a plant-derived alkaloid with potential therapeutic applications.

Purpose of the Study:

• To investigate the effects of anisodamine on lipid polymorphic phase behavior.
• To determine how anisodamine influences cardiolipin and dioleoylphosphatidylcholine liposomes.
• To elucidate the role of pH and drug-lipid ratios in anisodamine-induced structural changes.

Main Methods:

• Freeze-fracture electron microscopy was used to visualize liposome structures.
• Liposomes composed of cardiolipin and dioleoylphosphatidylcholine were prepared.
• Varying pH conditions and anisodamine concentrations were employed.

Main Results:

• Anisodamine induced lipidic particle formation in cardiolipin liposomes at pH 7.0.
• Hexagonal HII tubes were observed in cardiolipin liposomes at pH 8.8.
• Lipidic particles were also formed in dioleoylphosphatidylcholine liposomes at a 4:1 anisodamine to lipid ratio.

Conclusions:

• Anisodamine significantly alters the polymorphic phase behavior of cardiolipin and dioleoylphosphatidylcholine liposomes.
• The observed structural changes are dependent on environmental factors like pH and drug concentration.
• These findings provide insights into the interaction of anisodamine with lipid bilayers.