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Extraction Method :
The preparation and consumption of therapeutic herbs
has progressed through time from vaguely measured formulas
and dosages to specifically quantified amounts. Irregularity
and uncertainty in the preparation of medicines was
a serious shortcoming till date. But with the advent
of standardization procedures, this flaw has been reasonably
solved. There are several extraction methods for making
resins and extracts from plants, and each will be discussed
briefly below. Some plants contain alkaloids as part
of their chemical composition, and these different alkaloids
will extract into different solvents. For example, Blue
Lotus contains alkaloids that will only extract into
alcohol, whereas Amanita muscaria contains an alkaloid
that will extract into water, but will be destroyed
in alcohol. When doing resin extractions from plants,
it is important to know what chemical compounds will
extract into what solvents.
1. Solvent Extraction:
A hydrocarbon solvent is added to the plant material
to help dissolve the essential oil. When the solution
is filtered and concentrated by distillation, a substance
containing resin (resinoid), or a combination of wax
and essential oil (known as concrete) remains.
From the concentrate, pure alcohol is used to extract
the oils or fats. When the alcohol evaporates, the oil
is left behind.
This is not considered the best method for extraction
of essential oils, as the solvents can leave a heavy
residue behind, but it's great for making resins for
this very reason.
2. High Pressure CO2 Extraction/ Supercritical
Carbon Dioxide extraction:
Only recently developed, these methods
use Carbon Dioxide to extract the alkaloids, essential
oils, or resins from the plant when liquefied under
pressure.
Once the liquid depressurizes, the carbon dioxide returns
to a gaseous state, and only pure essential oil, resins,
or alkaloids remain.
The lower pressure CO2 extraction involves chilling
carbon dioxide to between 35 and 55 degrees F, and pumping
it through the plant material at about 1000 psi. The
carbon dioxide in this condition is condensed to a liquid.
Supercritical CO2 extraction (SCO2) involves carbon
dioxide heated to 87 degrees F and pumped through the
plant material at around 8,000 psi – under these
conditions, the carbon dioxide is likened to a 'dense
fog' or vapor. With release of the pressure in either
process, the carbon dioxide escapes in its gaseous form,
leaving the essential oil behind.
These carbon dioxide methods have a couple of advantages:
Like steam distillation, there are no solvent residues
left behind, and the resultant product is quite pure.
Like solvent extraction, there is no heat applied to
the plant material or essential oil to alter it in any
way. The oil produced is very accurate with respect
to the original state of the plant. The CO2 methods
also are the most efficient, producing the most oil
per amount of plant (one of the reasons for the high
cost of essential oils is the low yield of oil from
most plants – one ton of Rose petals produces
less than 1 pound of oil, for example). The efficiency
of CO2 extraction is particularly important when rare
or endangered plant species are involved, such as Indian
Sandalwood oil – less of the precious plant is
needed to produce an equivalent amount of oil.
3. Naturally Concentrated herbs
- This method yields herb concentrate by the application
of natural methods.
- Fortified herbal extracts:
Bioefficiency of the herbs can be improved
to large extent by our unique natural methods.
4. Whole herb extracts:
They are extracts of the whole herb with all the useful
and effective soluble compounds extracted. They contain
all components except nonsoluble compounds (such as
cellulose and fiber.), and noneffective or toxic ones.
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