Extraction of lichen bioactive compounds using volatile natural deep eutectic solvents and comparative analytical...

Area of Science:

• * Natural Product Chemistry
• * Phytochemistry
• * Pharmacognosy

Background:

• * Lichens produce diverse bioactive secondary metabolites with significant pharmacological potential.
• * Efficient extraction of these lichen metabolites, including depsidones and depsides, presents a considerable challenge.
• * Key target compounds include physodalic acid, physodic acid, 3-hydroxyphysodic acid, atranorin, and chloroatranorin.

Purpose of the Study:

• * To optimize extraction methods for key lichen metabolites from Hypogymnia physodes and other lichen species.
• * To compare traditional and advanced extraction techniques for yield and selectivity.
• * To evaluate green extraction approaches using volatile natural deep eutectic solvents (VNADES).

Main Methods:

• * Comparative analysis of Accelerated Solvent Extraction (ASE), maceration, and VNADES.
• * Optimization of extraction parameters: solvent type, ratio, duration, and temperature.
• * Evaluation of rotary evaporation versus lyophilisation for drying bioactive extracts.

Main Results:

• * ASE combined with acetone demonstrated high selectivity for lichen acid extraction, minimizing solvent use and time.
• * Optimized VNADES extraction parameters (menthol/camphor 1.5:1, L/S 100:1, 40°C, 30 min) maximized metabolite yield.
• * Rotary evaporation was identified as a cost-effective and rapid drying method, preserving compound integrity.

Conclusions:

• * ASE offers an efficient and selective method for extracting lichen acids.
• * VNADES present a promising green chemistry approach for lichen metabolite isolation.
• * Rotary evaporation is a suitable alternative to lyophilisation for drying lichen extracts.