Quantitative analysis of flavanones and chalcones from willow bark

Area of Science:

• Phytochemistry
• Analytical Chemistry
• Pharmacognosy

Background:

• Willow bark extracts are traditionally used for pain, fever, and inflammation.
• Salicylic alcohol derivatives and polyphenols contribute to willow bark's therapeutic effects.
• Current European Pharmacopoeia analysis primarily focuses on salicylic derivatives, neglecting other active compounds.

Purpose of the Study:

• To develop an effective quantification method for flavanone and chalcone glycosides in Salix species.
• To enable comprehensive analysis of active compounds in willow bark and its preparations.
• To improve the quality control of willow bark-based products.

Main Methods:

• Developed a two-step hydrolysis (acidic then enzymatic) to convert glycosides to aglycones (naringenin, eriodictyol).
• Utilized High-Performance Liquid Chromatography (HPLC) for quantifying the aglycones.
• Validated the method for Limit of Detection (LOD), Limit of Quantification (LOQ), precision, accuracy, and robustness.

Main Results:

• Successfully hydrolyzed and quantified 5-O- and 7-O-glucosides of naringenin, eriodictyol, and chalconaringenin.
• Achieved low LOD (0.77 μM naringenin, 0.45 μM eriodictyol) and LOQ (2.34 μM naringenin, 1.35 μM eriodictyol).
• Demonstrated method robustness regarding sample weight but noted susceptibility to enzyme degradation.

Conclusions:

• The developed HPLC method is effective for quantifying diverse flavanone and chalcone glycosides in willow bark.
• This method enhances the analytical capabilities for willow bark quality assessment.
• Provides a foundation for better understanding and utilizing the full spectrum of willow bark's active compounds.