Table 2: A brief summary of various extraction methods for natural products [14, 15].

Method Solvent Temperature Pressure Time Volume of Organic Solvent Consumed Polarity of Natural Products Extracted
Soxhlet extraction [16, 17] Methanol, ethanol, or mixture of alcohol and water Under heat depending on solvent used Atmospheric Long Moderate Dependent on extracting solvent
Maceration [17-19] Methanol, ethanol, or mixture of alcohol and water Room temperature Atmospheric Long Large Dependent on extracting solvent
Percolation [20, 21] Water, aqueous and non-aqueous solvents Room temperature, occasionally under heat Atmospheric Long Large Dependent on extracting solvent
Decoction [22-26] Water Under heat Atmospheric Moderate None Polar compounds
Infusion [19, 26, 27] Water Under heat Atmospheric Short Moderate Polar compounds
Ultrasound-assisted
extraction [28-32]
Methanol, ethanol, or mixture of alcohol and water Room temperature, occasionally Under heat Atmospheric Short Moderate Dependent on extracting solvent
Pressurized liquid extraction [33-35] Water, aqueous and non-aqueous solvents Under heat High Short Small Dependent on extracting solvent
Reflux extraction [26, 36] Aqueous and non-aqueous solvents Under heat Atmospheric Moderate Moderate Water, aqueous and non-aqueous solvents
Supercritical fluid extraction [37-40] Supercritical fluid (usually S-CO2), sometimes with modifier Near room temperature High Short None or small Nonpolar to moderate polar compounds
Subcritical water extraction [41-45] Water Under heat High Moderate Small Nonpolar to moderate polar compounds
Microwave assisted extraction [32, 46, 47] Water, aqueous and non-aqueous solvents Room temperature, occasionally under heat Atmospheric Short None or moderate Water, aqueous and non-aqueous solvents
Enzyme assisted extraction [32, 48-51] Water, aqueous and non-aqueous solvents Room temperature, or heated after enzyme treatment Atmospheric Moderate Moderate Water, aqueous and non-aqueous solvents
Hydro distillation and steam distillation [52, 53] Water Room temperature Atmospheric Long None Essential oil (usually non-polar)