Chromatographic fingerprint development for herbal extracts: a screening and optimization methodology on monolithic...

Area of Science:

• Pharmacognosy
• Analytical Chemistry
• Quality Control

Background:

• Herbal medicines are widely used globally for health, necessitating reliable identification and quality assessment methods.
• Fingerprint chromatography, recognized by the World Health Organization, is a key technique for evaluating medicinal herbs.
• Establishing optimal chromatographic conditions is essential for maximizing peak capacity and achieving reliable herb identification.

Purpose of the Study:

• To develop and propose a standardized methodology for creating fingerprint chromatograms of medicinal herbs using high-performance liquid chromatography (HPLC).
• To optimize experimental conditions for both ultra-violet (UV) and evaporative light scattering (ELS) detection in HPLC fingerprinting.
• To evaluate the effectiveness of monolithic C18 columns and various organic modifiers for herb analysis.

Main Methods:

• A two-phase methodology involving screening and optimization was employed for developing fingerprint chromatograms.
• Monolithic C18 columns were utilized as stationary phases, with several organic modifiers tested to establish gradient elution systems.
• Experimental conditions including detection wavelength, column length, flow rate, and gradient slope were optimized for four specific herbs: Liquorice, Cascara, Curcuma, and Artichoke.

Main Results:

• Specific linear gradient elution systems of acetonitrile were identified for each herb during the screening phase.
• Evaporative light scattering (ELS) detection did not offer significant advantages over ultra-violet (UV) detection for these herbs.
• Optimal conditions for all four herbs were determined as: 254 nm detection wavelength, 300 mm column length, 2 ml/min flow rate, and a 50-minute gradient time.

Conclusions:

• A standardized HPLC methodology for herb fingerprinting has been proposed, simplifying identification and quality control.
• The determined optimal conditions (254 nm, 300 mm column, 2 ml/min flow, 50 min gradient) show potential for broad application across different herb species.
• Further validation of these conditions across diverse case studies could lead to a simplified, more efficient optimization stage in future analyses.