Flavonoid Glycosides and Phenolic Acids from Inula Oculus-Christi Modulate Membrane Organization and Provide...

Area of Science:

• Biochemistry and Biophysics
• Membrane Biology
• Natural Product Chemistry

Background:

• Oxidative stress damages cell membranes through lipid peroxidation.
• Polyphenols (PPs) are known for their antioxidant capabilities.
• Inula oculus-christi is a source of potential PPs.

Purpose of the Study:

• To investigate the structural and antioxidant effects of PPs from Inula oculus-christi.
• To evaluate flavonoid glycosides (FGs) and phenolic acids (PAs) in model and cell membranes.
• To understand how PPs affect membrane integrity under oxidative stress.

Main Methods:

• Steady-state fluorescence spectroscopy.
• DPH and Laurdan spectroscopy for membrane lipid order.
• DPH-TEMPO fluorescence quenching for lipid raft formation.
• Fluorescence quenching of cis-parinaric acid for antioxidant capacity.

Main Results:

• Both FGs and PAs provided significant antioxidant protection, with FGs being more effective.
• PPs promoted lipid raft formation, especially in cholesterol-rich membranes.
• PPs modulated membrane order, increasing it in liquid-disordered phases and decreasing it in liquid-ordered phases.
• FGs significantly enhanced membrane fluidity in A549 cells compared to MDCKII cells.

Conclusions:

• PPs from Inula oculus-christi possess both structural and antioxidative properties.
• FGs and PAs contribute to preserving membrane integrity against oxidative damage.
• The findings suggest a dual role for PPs in membrane biophysics and protection.