Antioxidative caffeoylquinic acids and flavonoids from Hemerocallis fulva flowers

Area of Science:

• Phytochemistry
• Pharmacology
• Natural Products Chemistry

Background:

• Hepatotoxicity induced by Tumor Necrosis Factor-α (TNF-α) involves reactive oxygen species (ROS) production in hepatocytes.
• Hemerocallis fulva flowers are a potential source of bioactive compounds for screening hepatoprotective agents.

Purpose of the Study:

• To isolate and characterize novel and known compounds from Hemerocallis fulva flowers.
• To evaluate the free radical scavenging activity of isolated compounds in HepG2 cells.
• To develop an analytical method for identifying key compounds.

Main Methods:

• Aqueous ethanol extraction of Hemerocallis fulva flowers.
• Isolation of compounds using chromatographic techniques.
• Structure elucidation by spectroscopic data analysis (NMR, MS).
• Evaluation of free radical scavenging activity in TNF-α-induced HepG2 cells.
• Development of an Ultra-Performance Liquid Chromatography (UPLC) method.

Main Results:

• Three new polyphenols (1-3) and 16 known compounds (4-19) were isolated.
• Compounds 1-3 are reported as first isolated natural products.
• Caffeoylquinic acid derivatives (4-7) were identified as major components with potent free radical scavenging activity.
• These caffeoylquinic acid derivatives are reported for the first time from H. fulva flowers.
• A UPLC method was successfully developed for simultaneous separation and identification of caffeoylquinic acids and flavonoids.

Conclusions:

• Hemerocallis fulva flowers contain bioactive polyphenols, including novel compounds.
• Caffeoylquinic acid derivatives from H. fulva flowers exhibit significant free radical scavenging activity, suggesting hepatoprotective potential.
• The developed UPLC method provides an efficient tool for quality control and analysis of these compounds.