Water as a Solvent

  • Water as an Active Solvent

    • Water should not be viewed as basic; it actively dissolves and extracts chemicals from plant matter.

    • Different solvents extract different chemicals; hence the choice of solvent is crucial.

  • What Water Dissolves

    • Cold Water: Extracts gums, sugars, bitter compounds, some colors, and mineral salts from plants.

    • Extracts glycosides, proteins, enzymes, and especially tannins.

      • Example: Tannins contribute to the dry taste of black tea, affecting mucus membranes in the mouth.

    • Alkaloids can partially dissolve in water, especially in salt form.

    • Oils and Resins: Low solubility in water; better extracted with alcohol or oil.

  • Methods of Extraction

    • Infusion: Herb is steeped in water without further heating.

      • Best for delicate plant parts (leaves, flowers).

    • Decoction: Herb is boiled in water to extract nutrients.

      • Suitable for harder plant parts (e.g. bark, roots).

      • Boiling breaks down plant cells and lignin, enhancing extraction.

  • Advantages of Using Water

    • Cost-effective: Widely available and easy to obtain.

    • Universal Solvent: Capable of extracting a wide array of chemicals from plants.

    • Non-toxic: Safe compared to alcohol and oils, which can be flammable.

    • Neutral Flavor: Encourages patient compliance due to its compatibility with food and drink.

    • Personal Involvement: Making a herbal tea becomes a familiar routine, enhancing treatment adherence.

  • Disadvantages of Using Water

    • Non-selective Extraction: Water pulls out most chemicals, which may not be desired in some cases.

    • Absorption by Plant Material: Plant matter swells, absorbing the liquid and reducing the yield of the final product.

    • Microbial Growth: Water is prone to bacterial and mold contamination.

      • Infusions and decoctions spoil quickly; should be consumed the same day.

      • Fresh infusion required for subsequent uses in products.

    • Enzyme Activity and Hydrolysis: Hydrolysis can lead to cell bursting, leaking active compounds into the solution.

      • Concentrating decoction through heat can lead to loss of volatile components utilized for therapeutic effects.