Silymarin extraction from milk thistle using hot water

Area of Science:

• Green Chemistry
• Phytochemistry
• Extraction Technology

Background:

• Growing demand for sustainable and eco-friendly solvents in phytochemical extraction.
• Hot water is emerging as a promising alternative to traditional organic solvents.
• Milk thistle (Silybum marianum) is a valuable source of bioactive compounds like silymarin and taxifolin.

Purpose of the Study:

• To investigate the efficacy of hot water extraction for milk thistle compounds at elevated temperatures (>100°C).
• To determine the impact of temperature on extraction yield and kinetics.
• To assess the stability and degradation of target compounds under hot water extraction conditions.

Main Methods:

• Extraction of milk thistle using hot water at temperatures ranging from 100°C to 140°C.
• Analysis of silymarin and taxifolin yields at different temperatures and extraction times.
• Kinetic analysis of compound degradation at elevated temperatures.

Main Results:

• Extraction time to reach maximum yield significantly decreased with increasing temperature (from 200 to 55 min).
• Maximum extraction yields for silymarin compounds and taxifolin did not improve with higher temperatures.
• Significant degradation of unprotected silymarin compounds was observed at 140°C, following first-order kinetics.

Conclusions:

• While hot water extraction accelerates the process for milk thistle, higher temperatures do not increase compound yield due to degradation.
• Optimizing temperature is crucial to balance extraction efficiency and compound stability in green solvent applications.
• Further research is needed to mitigate degradation and maximize the recovery of valuable milk thistle compounds using hot water extraction.