Selective extraction and stabilization of bioactive compounds from rosemary leaves using a biphasic NADES

Area of Science:

• Green Chemistry
• Natural Product Extraction
• Phytochemistry

Background:

• Rosemary (Rosmarinus officinalis) is a rich source of bioactive compounds with significant antioxidant properties.
• These compounds are valuable in pharmaceutical, food, and cosmetic industries.
• Natural deep eutectic systems (NADESs) are emerging as eco-friendly solvents for extracting bioactive compounds due to their low toxicity and biodegradability.

Purpose of the Study:

• To investigate the efficacy of NADESs for extracting key bioactive compounds (rosmarinic acid, carnosol, carnosic acid, caffeic acid) from rosemary.
• To explore the selective extraction capabilities of different NADESs based on compound polarity.
• To assess the stability of extracted bioactive compounds within NADESs over time.

Main Methods:

• Extraction of rosemary compounds using two distinct NADESs: menthol:lauric acid (Me:Lau, 2:1) for nonpolar compounds and lactic acid:glucose (LA:Glu, 5:1) for polar compounds.
• Utilized heat and stirring (HS) and ultrasound-assisted extraction (UAE) techniques.
• Performed simultaneous extraction using a biphasic system of the two NADESs.
• Quantified extracted compounds using High-Performance Liquid Chromatography (HPLC) to determine stability over time.

Main Results:

• The Me:Lau (2:1) NADES selectively extracted nonpolar compounds like carnosic acid and carnosol.
• The LA:Glu (5:1) NADES preferentially extracted polar compounds, notably rosmarinic acid.
• A biphasic system of LA:Glu (5:1)/Me:Lau (2:1) enabled simultaneous, single-step extraction of polar and nonpolar compounds.
• Bioactive compounds from rosemary demonstrated significant stability in NADESs over three months, outperforming methanol extraction.

Conclusions:

• NADESs provide a selective and efficient method for extracting diverse bioactive compounds from rosemary.
• The biphasic NADES system allows for simultaneous extraction of compounds with different polarities in a single step.
• NADESs effectively stabilize extracted bioactive compounds, offering a promising alternative for industrial applications compared to conventional solvents.