Determination of the Polyphenol Composition of Raspberry Leaf Using LC-MS/MS

Area of Science:

• Phytochemistry
• Food Science
• Nutraceuticals

Background:

• Raspberry leaf (RL) is a cultivation by-product with potential bioactive compounds.
• Polyphenolic composition of RL requires further extensive study.

Purpose of the Study:

• Evaluate (poly)phenolic content in six RL samples from diverse locations.
• Determine the impact of brewing duration on accessible phenolic compounds.

Main Methods:

• Utilized Liquid Chromatography-Mass Spectrometry (LC-MS) to analyze 52 polyphenolic constituents.
• Extracted RL tea using methanol/acidified water with sonication.
• Brewed RL tea (2 g/200 mL) at various times (0.5-20 min) to assess polyphenol release.

Main Results:

• Total polyphenol content ranged from 358.66 to 601.65 mg/100 g across samples.
• Ellagitannins were predominant (155.27–394.22 mg/100 g), followed by flavonoids and phenolic acids.
• Maximum polyphenol yield (505.65 mg/100 g) occurred at 5 min brewing time, with ellagic acid peaking at this time.

Conclusions:

• RL possesses a significant concentration of polyphenols, notably ellagic acid.
• Consumption of RL may enhance daily intake of beneficial non-nutrient compounds.
• Optimal steeping time of 5 minutes maximizes polyphenol extraction from RL tea.