Octyl gallate: An antioxidant demonstrating selective and sensitive fluorescent property

Area of Science:

• Biochemistry
• Analytical Chemistry
• Fluorescence Spectroscopy

Background:

• Octyl gallate (OG) is a recognized antioxidant with inherent fluorescent properties.
• The fluorescence of OG is selectively modulated by interactions with proteins like human serum albumin (HSA) and bovine serum albumin (BSA).
• Understanding these interactions is crucial for developing novel analytical methods.

Purpose of the Study:

• To investigate the fluorescence enhancement mechanism of Octyl gallate (OG) in the presence of Human Serum Albumin (HSA) and Bovine Serum Albumin (BSA).
• To explore the potential application of OG's fluorescence properties for quantitative analysis.
• To elucidate the role of protein structure in modulating OG fluorescence.

Main Methods:

• Fluorescence spectroscopy was employed to measure emission intensity and lifetimes.
• Molar ratios of OG to HSA/BSA were varied to study binding effects.
• Förster resonance energy transfer (FRET) was analyzed to understand energy transfer dynamics.
• Complex formation between OG and HSA was studied to determine prerequisites for fluorescence enhancement.

Main Results:

• OG fluorescence intensity increased significantly (approx. 49-fold with HSA, 11-fold with BSA) at a 1:1 molar ratio.
• The fluorescence lifetimes of HSA and BSA decreased upon interaction with OG.
• Evidence of Förster resonance energy transfer (FRET) was observed between OG and the albumins.
• Formation of a stable complex between OG and HSA was identified as essential for efficient fluorescence enhancement.

Conclusions:

• The structural features of HSA and BSA facilitate selective fluorescence enhancement of OG.
• The interaction mechanism involves Förster resonance energy transfer (FRET) and stable complex formation.
• The selective and sensitive fluorescence enhancement of OG offers potential for its quantification using methods like standard addition.