Natural Deep Eutectic Solvents as Green Alternatives for Extracting Bioactive Compounds from Sideritis Taxa with...

Area of Science:

• Phytochemistry
• Green Chemistry
• Natural Product Extraction

Background:

• Mountain tea (Sideritis taxa) is rich in bioactive compounds.
• Conventional extraction solvents raise environmental concerns.
• Natural Deep Eutectic Solvents (NADESs) offer a sustainable alternative.

Purpose of the Study:

• To evaluate NADESs for extracting bioactive compounds from Sideritis clandestina and Sideritis raeseri.
• To compare NADESs efficiency with conventional solvents (water, ethanol).
• To assess the antioxidant activity and phenolic profiles of the extracts.

Main Methods:

• Five NADESs were formulated using betaine, glycerol, glucose, urea, citric acid, and sucrose.
• Extraction efficiency was tested against water and 70% ethanol.
• Total phenolic content (TPC) and antioxidant activity (FRAP, DPPH assays) were measured.
• Secondary metabolites were identified using HPLC-MS.

Main Results:

• Water was an ineffective extraction solvent.
• The betaine-glycerol-glucose NADES (BGG4) showed comparable or superior extraction efficiency and antioxidant activity to 70% ethanol.
• BGG4 extracts were rich in chlorogenic acid, verbascoside, and acetylated allosyl hypolaetin glycosides.
• Sideritis clandestina extracts contained higher levels of secondary metabolites than Sideritis raeseri extracts.

Conclusions:

• NADESs, particularly BGG4, are effective and sustainable solvents for Sideritis bioactive compound extraction.
• This highlights the potential of NADESs for developing natural cosmetic products.
• Further research into NADES applications in natural product chemistry is warranted.