Extracting with Solvents
Apart from the crude drugs, the base materials of compounding, are its solvents and carriers. The solvents are alcohol (ethanol) and distilled water. The carriers are solutions, emulsions, mucilages, syrups, water and alcohol. An essential part of some carrier substances are the fixed oils and waxes. By far, the most important substance is alcohol, without it, a complete extraction of herb constituents is not possible.
Solvents used for Extraction Purposes
From the standpoint of pharmacy, the purpose
of a solvent is to remove from a solid, either in part or in its
entirety, such substances that may be rendered to a liquid. In
chemistry the solvent is known as the 'SOLUTION' and the extracted material
as the "SOLUTE'. In pharmacy the solvent used for extraction is
referred to as the "MENSTRUUM'. When the material has been extracted, the
menstruum is known as the "VEHICLE' or "CARRIER" of the extracted material.
Solvents used for Herbal Preparations
The majority of solvents are toxic to a greater or lesser degree. It should also be remembered that it is not possible to remove all traces of a solvent from an extracted substance. There are no perfect solvents, each one has its drawbacks. When considering the suitability of a solvent it should meet the following criteria;
The alcohol of the British Pharmacopoeia, is a
95% mixture of ethanol and water, which is obtained by the
distillation of fermented sugars or by synthesis. It is a clear, colorless,
volatile liquid. It has a burning taste, with a characteristic odor
and boils around 78�C. It is miscible with water in all proportions,
however, when mixing with water, a contraction of volume and a rise in
temperature occurs. The mixture must cool to 20�C before it is adjusted
to its final volume. Its Specific Gravity (SG) at 20�/20�C (atmosphere 20�C
- liquid 20�C), is 0.8119, for practical purposes we can say 0.800,
its molecular formula is
The alcohol produced by such methods is cheaper, and therefore, attractive. On analysis, its formula is C2H5OH. The physiological effects are manifestly different to those of alcohol produced by fermentation methods. What is produced is determined by the strain of the yeast and the material (substrata) upon which the yeast must work. The perfumers preference, is for a grain based alcohol to produce the ethereal and elusive top notes of fine perfumes. Whereas, for the herbal pharmacist, a fruit or herb based alcohol is the preferred solvent.
Alcohol from Carbohydrate
The carbohydrates are found as complexes in all higher plants, those that occur in the lower plants, such as the ferns, mosses and their allies, are substantially the same, therefore, with the correct treatment, we may use them as fermentation substrata, with or without, the addition of sucrose. Remember that carbohydrate synthesis in plants is photosynthesis. This is an important point for the Spagyric Pharmacist, because the alcohol used to extract a plant, is made from the same species. The following table may be used as a rule of thumb to estimate the amount of plant material required, to produce a given amount of alcohol.
The rule is; that all such plant parts must be treated with amylase to convert the carbohydrate to fermentable sugars. We may see from the above table, that the leaf part of the plant contains the least amount of carbohydrate.
The conversion of sugars by yeast to alcohol, is performed by enzymes; over a dozen have been identified; the total of which is called the ?ZYMASE COMPLEX', all of which are involved in the fermentation process. Not all of the functions are understood. The most important enzymes, from the alcohol production point of view, may be summarized as follows.
It should be understood, that the clear cut divisions between substances and sugars that are shown in table only indicate the major type of sugar to be found in a plant, for they will undoubtedly contain a complex of sugars.
Honey, Malt or Molasses may be treated as
mono-saccharide. Commence the process at the 2nd treatment.
Distillation is an ancient technique known to
many cultures. Western science historians usually credit its discovery
to the Arabs in the 11th or 12th century AD. However translations of
far older Indian and Chinese medical documents mention products that
would need spirits of wine to produce. Therefore would it be
reasonable to assume the technique arrived in Arabia from points East and
then percolated into Europe, via Spain, which then, were strongly influenced
by Arab culture.
Fractional distillation is another technique
which is used to separate the different components of a mixture.
Separation may also be achieved by simple distillation, but the
technique is discontinuous and can become tedious. Whereas the
fractional technique is a continuous process that conserves time and
The Pharmageddon Herbal
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