Extraction of Medicinal Plants

Extraction of Medicinal Plants

• Extraction is the initial step in separating desired natural products from raw materials.
• Extracted products include alkaloids, flavonoids, phenolics, glycosides, and steroids.
• These compounds exhibit antioxidant, anticancer, antimicrobial, anti-inflammatory, antidiabetic, and antihypertensive properties.

Mechanism of Extraction

• Extraction involves dissolving desired components from plant matter.
• Solvent interacts with plant cells to extract desired compounds.

Factors Affecting Extraction

• Solvent selection: Different solvents dissolve different compounds effectively.
• Ratio of solute to solvent: The appropriate solute-solvent ratio affects extraction efficiency.
• Solute size: Smaller particles extract more readily.
• Solvent temperature: Higher temperatures increase extraction rate.
• Extraction time: Longer extraction time usually yields more extract.

Steps in Extraction Process

• Size reduction: Crushing or grinding plant material increases surface area.
• Extraction: Mixing plant material with solvent to dissolve compounds.
• Filtration: Removing undissolved plant matter to purify extract.
• Concentration: Removing solvent to obtain concentrated extract.

Types of Extraction

• Maceration: Allowing plant material to soak in solvent at room temperature for several days.
• Digestion: Similar to maceration but with gentle heating, increasing solvent efficiency.
• Decoction: Boiled plant material in water for a defined time.
• Infusion: Pouring water (hot or cold) over plant materials for a specific time.
• Percolation: Packed plant material allowing solvent to flow through.
• Soxhlet extraction: Continuous hot percolation using specific apparatus.
• Supercritical fluid extraction: Extraction using supercritical fluids like carbon dioxide.

Advantages of Different Extraction Methods

• Economic method: Large amounts of drug can be extracted with small quantities of solvents.
• Microwave-assisted extraction: Effective and less time consuming, with lower solvent consumption.
• Supercritical fluid extraction: Rapid extraction with solvents which are easily removed and non-toxic.

Procedure for Supercritical Fluid Extraction

• Equipment includes a pump, extraction chamber, pressure controller and collection device.
• Material is placed in extraction chamber and supercritical fluid (carbon dioxide) is pressurized.
• Component recovery depends on lowering the solvent's density (lowering temperature or reducing pressure).

Limitations of Supercritical Fluid Extraction

• High costs and pressure requirements.

Counter Current Extraction

• Liquid-liquid extraction method.
• Multiple liquid phases flow in opposing directions.
• Separates components based on differential solubility in the two immiscible solvents.

Separation of Components

• Distribution coefficients are used to quantify component distribution between two phases.
• A higher distribution coefficient indicates stronger attraction for that solvent.

Various Apparatus Used

• Caraig apparatus: Used for liquid-liquid extraction with a series of tubes.

Distillation Methods

• Direct steam distillation: Separates temperature-sensitive substance by using steam.
• Water distillation: Simple method to extract water-soluble components.
• Water and steam distillation: Used for separating volatile oils.

Extraction Method (Solution Method)

• Effective for sensitive or small quantities of compounds.
• The procedure is used to extract compounds from flowers.

Enfleurage

• Used in delicate flowers to extract volatile oils.
• Fat absorbs the volatile oils then extracted with alcohol.

Explore the intricate process of extracting medicinal compounds from plants in this quiz. Understand the various types of extracts, the mechanisms involved, and the factors that influence extraction efficiency. Test your knowledge on alkaloids, flavonoids, and more.