Solvent Selection in Pharmacognosy

Solvent Selection in Extraction in Pharmacognosy

Importance of Solvent Selection

• Selection of a suitable solvent is crucial in extraction as it affects the quality and quantity of the extracted phytoconstituents
• A good solvent should be able to extract the desired compounds while leaving behind the unwanted ones

Factors Affecting Solvent Selection

• Polarity: Solvents with similar polarity to the phytoconstituents are more effective in extraction
• Solubility: Solvent should be able to dissolve the phytoconstituents of interest
• Selectivity: Solvent should selectively extract the desired compounds while minimizing the extraction of impurities
• Toxicity: Solvent should be non-toxic and safe for use
• Cost and Availability: Solvent should be cost-effective and easily available
• Environmental Impact: Solvent should have a minimal environmental impact

Types of Solvents Used in Extraction

• Polar solvents:
  • Water
  • Methanol
  • Ethanol
  • Acetone
• Non-polar solvents:
  • Hexane
  • Chloroform
  • Ether
• Intermediate polarity solvents:
  • Ethyl acetate
  • Isopropyl alcohol
  • Acetonitrile

Solvent Selection Criteria for Different Phytoconstituents

• Alkaloids: Polar solvents like water, methanol, and ethanol are effective
• Glycosides: Polar solvents like water and methanol are effective
• Terpenes: Non-polar solvents like hexane and chloroform are effective
• Flavonoids: Polar solvents like methanol and ethanol are effective

Solvent Selection in Extraction in Pharmacognosy

Importance of Solvent Selection

• Suitable solvent selection is crucial in extraction as it directly affects the quality and quantity of extracted phytoconstituents
• A good solvent should selectively extract desired compounds while leaving behind unwanted ones

Factors Affecting Solvent Selection

Polarity and Solubility

• Solvents with similar polarity to phytoconstituents are more effective in extraction
• Solvent should be able to dissolve phytoconstituents of interest

Selectivity and Toxicity

• Solvent should selectively extract desired compounds while minimizing impurities
• Solvent should be non-toxic and safe for use

Practical Considerations

• Solvent should be cost-effective and easily available
• Solvent should have a minimal environmental impact

Types of Solvents Used in Extraction

Polar Solvents

• Water
• Methanol
• Ethanol
• Acetone

Non-Polar Solvents

• Hexane
• Chloroform
• Ether

Intermediate Polarity Solvents

• Ethyl acetate
• Isopropyl alcohol
• Acetonitrile

Solvent Selection Criteria for Different Phytoconstituents

Alkaloids and Glycosides

• Polar solvents like water, methanol, and ethanol are effective for alkaloid extraction
• Polar solvents like water and methanol are effective for glycoside extraction

Terpenes

• Non-polar solvents like hexane and chloroform are effective for terpene extraction

Flavonoids

• Polar solvents like methanol and ethanol are effective for flavonoid extraction