Preparing Medicinal Plants

Introduction

Harvesting Medicinal Plants

Main Preparations : Plants in Powder, Infusion, Decoction and Maceration,
                                  Alcohol Tincture and Mother Tincture, Essential Oils

Commercial Phytomedicines

Around the World : Creole Medicine, Medicine with the Amerindian of the Guyanas
                            Plants in Polynesia, Indigenous Australian Medicine
Introduction TOP

In tropico-equatorial areas, when people need medicinal plants, they mostly use those around without stocking or preserving them.

On the contrary, in very cold or very hot countries, we must use medicinal plants as they are flowering. We also try to preserve them in order to be able to reuse them later in the bad season.

In developped countries, even though it is not necessary to prepare remedies for oneself, people are fairly satisfied to heal themselves using "natural" methods. They are cheap and enable not to consume synthetic medicines whose effects are much too powerful or improper. Medicinal plants often are the only one way to heal in many countries where health services are disorganized and synthetic medicines unavailable.
Harvesting Medicinal Plants
 TOP

Traditionally medicinal plants are preferably harvested in their natural environment. Nevertheless in many regions, plants become harder and harder to harvest because of:

  • the permanent increase of agricultural areas treated with pesticides -including pastures, hedges and fallows
  • the critical disappearance of some wild medicinal plants since they are either overexploited -to respond to the increasing demand from traders and merchants in medicinal plants of the pharmaceutical industry on a global scale- or weakened by the modifications of natural surroundings such as pollution, industrial agriculture, agroforestry, desertification and overgrazing.


Nowadays, most of the medicinal plants in great demand are cultivated in a reasonably organic manner. But sometimes fertilizers and pesticides are used intensively.
In any case, when harvesting wild plants, only the necessary amount of plant has to be deducted the amount of plants necessary; if possible, away from busy roads and agricultural areas; and finally we should ask a botanical guide, a pharmacist or a traditional practitioner to verify the identity of the medicinal plant needed.    


When is it Time to Harvest?

  • full plants: when flowering;

  • leaves: after complete development and if possible, before flowering;

  • flowers and sprays: right before total flowering;

  • roots of annual plants: at the end of the vegetative period, i.e. at the end of growth;

  • roots of bisannual plants: at the end of the vegetative dormancy of the first year and before the resumption of vegetative growth of the second year;

  • roots of perennial plants: during their second or third year; before becoming too rough and fibrous namely before the lignification process;

  • fruits and seeds: mature or very slightly before -if fruits are to be dried-;

  • tree bark: in winter or at the beginning of spring -during the dry season-; shrub bark after the hot season -at the end of the wet season.

Thanks to cold preservation or immersion of roots into water, medicinal plants are preserved for 24 to 48 hours. If they are not meant to be used, plants have to be desiccated (or transformed into mother tincture):

  • drying in the shade if possible, in an open and ventilated space: e.g. barn, solar furnace or drying terrace;

  • sometimes kiln drying -soft heat- in regions very sensitive to humidity and most of the time, for big fleshy roots after being cut into slides or into pieces.
After dehydration, plants are set into bunches when they are meant to be used or sold soon. Otherwise plants are preserved -in their full form, in snippets, in powder- in water and air-tight containers for 6 to 12 months.

   
Main Preparations of Herbal Remedies
Plants in Powder TOP

Properly desiccated plants are ground and used unprepared.
They may be blended with a little water or food. The taste is often outrightly unpleasant: it is mainly due to the bitterness that is much too strong for humans. That is why pills and capsules of dry powder ready to pop are prepared. They will dissolve into the stomach and/or the bowel.
Infusion, Decoction and Maceration TOP

The easiest way to extract the active principles from medicinal plants is by water.
Some components are sensitive to heat; others are difficult to combine in solution. Therefore water temperature and duration of water containment may be varied to extract specifically interesting components.
  • Infusion or Tea or Tisane
    the dry or fresh plant -sometimes in powder or in pieces- is covered with very hot or boiling water for 3 to 6 minutes. Then softly agitated and filtered.
    To be drunk warm or cold immediately. Infusion may be preserved in a cold place 6 to 12 hours.

  • Decoction or Concentrated Tea
    the dry or fresh plant -sometimes in powder- hashed or mashed is put into a container of cold water. Boil; let the mixture simmer 10 to 20 minutes; and filter.
    Decoction may be preserved 2 to 3 days in a cold place.

  • Aqueous Maceration
    maintain the fragmented medicinal plant in cold water, in a cool place for 12 to 24 hours; stir the mixture from time to time; and filter. To be drunk within 6 hours.
Alcohol Tincture and Mother Tincture TOP

By definition mother tincture is "a liquid preparation resulting from the solvent action of an alcoholic vehicle on fresh herbal drugs".

Mother tincture is obtained by maceration of fresh or stabilized plants in ethyl alcohol. If the plant is dry, the mixture is called alcohol tincture.
Even if the alcohol component may be unacceptable for some people, alcohol tincture and mother tincture are very interesting. They are easy to prepare; the product is fairly regular; the concentration in an active substance controllable: a good point for an easy prescription. Its preservation is really satisfying.

How to Prepare a Mother Tincture?
  • Screen and trim medicinal plants or fragments -defined beforehand with care-

  • Grind and let immediately macerate in ethyl alcohol 95°; add to the blend the amount of distilled water necessary to get a degree of about 60 to 70 alcohol;

  • At the same time, put aside a part of the fresh medicinal plant -which after being weighed- is dried out to the autoclave at 50°C for 12 to 24 hours. Weigh the mixture again to get its dry weight, that generally corresponds to 20-30% of the fresh weight;

  • The macerate is preserved in a cool and dark place in a water and air-tight container for 3 weeks; shake from time to time;
  • At the end of the 3 weeks, filter and also retrieve the liquid from pressing strongly out the residue of the macerated plant; blend the whole mixture;

  • Measure the liquid obtained; adjust the alcohol degree (60°) and the volume of tincture to get the requested ratio -compared with the theoretical weigh of the dry matter.
    In a tincture to 1/10 -the most common in France-: 1 litre of tincture corresponds either to 100 grammes of dehydrated medicinal plant or to 250-300 grammes of fresh plant.
    The other current ratios are 1/5 and 1/20.

 
For private and non-commercial uses, there is an easier method to prepare a tincture.
100 grammes of dry plant in 1 litre of alcohol 60° or 250 grammes of fresh plant in 1 litre of alcohol 70° produce -after fews weeks of maceration; filtration and expression of residue- an alcohol tincture about to 1/10 in alcohol 50°-60°. For a good preservation, tincture must not contain less than alcohol 45°.

If an alcohol tincture is concentrated by evaporation, the product is called fluid extract. The ratio -1/1- corresponds to 100 grammes of dry plant in 100 grammes of fluid extract, that is much more concentrated in active principles.
If evaporation is prolonged, the material is called soft extract. Its syrupy texture is similar to consistency of honey.

Alcohol tincture is very convenient: it may be used internally or externally. Alcohol tincture keeps several years in a cool and dark place (e.g. coloured or opaque glass), in a waterproof non-metallic container.
Alcohol tincture may be mixed with a lotion, a pomade, a cataplasm and an enema. Various herbal tinctures may be blended together.
Essential Oils TOP

By definition, essentials oils are "products that contain volatile principles from plant species".

How to Obtain and Condense Volatile Substances?
  • hot steam distillates volatile substances and then condenses them. With the difference of gravity essential oil gets separated from water;
  • when plant have secretory cavities their content is presssed out (e.g. in the citrus family);


There are other ways to prepare essential oils: extraction by volatile solvents, supercritical carbon dioxide extraction, extraction by a fatty solvent. All these techniques require very specialised tools and a specialist knowledge.

Nevertheless, volatile principles of essential oils may be retrieved with alcohol maceration such as alcohol tincture.

Besides the components of essential oils become volatile to heat. Therefore it is possible to:

  • heat leafy branches, aromatic wood, bark and seeds, resin (frankincense) and thus breathe the components of essential oils. They will be absorbed by airway.
  • dip aromatic leaves into very hot water and obtain an aromatic bath, remembering that the components of essential oils easily penetrate skin when bathing.

The components of essential oils are soluble in glycerids: glycerids may be used in a dissolved form but the process is easier with vegetable oils like those of coconut, olive, sweet almond, etc.. The preparation finally offers an aromatic oil. The oil contains a major part of essential oil but also other liposoluble components. (which is not always interesting)

PREPARATION: fill in half a container with the aromatic dry medicinal plant roughly ground; complete with the oil; let macerate for 2 to 4 weeks at room temperature and shake from time to time. Let oil settle, otherwise filter it with a clean cloth. Preserve this aromatic oil in tinted glass in a dark and cool place. Examples: monoï coconut oil, aromatic (or infused) oil of flowers (rose, St John's worth) or of labiates (thyme, rosemary, sage, etc.) .
These aromatic oils will be used as massage oils or in local skin application (St John's worth) or quite simply when cooking (thyme, rosemary).
Commercial Phytomedicines TOP

The pharmaceutical industry mainly offers:
preparations that correspond more or less to the whole plants:
  • packed fresh plant juice;
  • split or ground dry plants;
  • micronised dry powder;
  • dry powder of plant after cryogrinding;
  • full suspension of dry plant ground and stabilized.
extracts:
  • hydro-alcoholic extracts, similar to tincture, fluid extract or soft extract;
  • aqueous extracts, similar to infusions, decoctions, syrups;
  • dry and sometimes atomized extracts -in general called nebulisate-;
  • special: intrait, a fresh plant extract beforehand stabilized chemically; glycero-alcoholic macerate -at the heart of gemmotherapy- a little similar to mother tincture but with addition of glycerin to better extract some active principles of buds and very small branches; essential oil, that is at the base of aromatherapy.
Moreover pharmaceutical laboratories extract useful active substances; purify them; at times modify or use them to synthetize new molecules more or less toxic for the organism.
At the drugstore, there is a wide range of preparations that associate sometimes several plants, several modes of preparation.

Medicinal Plants around the World
Creole Medicine in the Antilles TOP

In the Antilles the Creole medicine advocates for infusion and decoction. Several plants may be blended together. People differentiate between tisane that refreshes and tea that warms up. Tea is less profuse in quantity than tisane. In the Creole mentality the opposition between hot and cold, between inflammation and cooling balances health. This notion also exists in Europe and in other countries.

If infusion and decoction are common, there is another preparation less common: thelooch. It is an aqueous extract concentrated by evaporation.

Alcoholic maceration -into rum of course, but also into cognac, brandy or cooked wines is a common process. Leaves, roots, wood and/or bark fragments, at times animals (e.g. heads of snake) may be added. Juice of plants is harvested by expression or after searing it lightly.

Traditionally in Africa but also in the Antilles-Guyanas, vegetable ashes treat skin lesions.Parents put easily their children into a bath of plants or spray them with it. Plasters and cataplasms of fresh plants are frequently used. People blend on a lesser scale dry plant and animal fat.
Medicine with the Amerindian of the Guyanas TOP

With the Amerindian of the Guyanas, plants are generally harvested, prepared and used during the day. Around villages, forests are omnipresent.

Every vegetable parts of plants are usable: leaf, bud, fruit, seed, flower, bark, wood, root, sap, latex and exudate.
Plants are macerating into cold water or prepared in decoction.
At times leaves are slowly cooked at a low temperature above embers. Afterwards the material is ground or transformed into a medicinal smoke.

Juice of leaves and buds is gathered. Bark is softened by more or less searing it.
The Amerindian absorb healer's preparations through the mouth. Nevertheless people currently pour a calabash containing medicinal preparation on their heads and shoulders as an external washing. People use also the preparation as a gargle.

Steam bath with plants is rather reserved to shamans or healers so as to favour their visions.
Bodily friction with leaves or bark -sometimes seared lightly to soften them or to make them sweat-; plasters of plants and of sap are common.
Medicinal Plants in Polynesia TOP

Polynesian people do not drink any infusion or decoction.

Medicinal plants -which include full plants, leaves, flowers, fruits, roots, wood, bark- are generally ground with a stone pestle and blended with:
  • green coconut water -to degres of maturation that depend on recipes-
  • or with coconut milk -prepared in a special manner, at times with green walnuts-
  • or with coconut oil. Brown sugar is sometimes added to reduce bitterness.
The preparation is carefully filtered with vegetable fibers.

In some cases the plant ground or its pure juice is directly administered on the affected and/or painful part.
Plaster -kept on the harm- and the liminent are well-known by the Polynesian.
Most of the recipes associate various plants.
Indigenous Australian Medicine TOP


First colonialists considered Indigenous Australians as an healthy people even though they lived in very difficult conditions. Indigenous people resort to plants from the Australian bush to heal wounds and ulcers, to fight against fairly common diarrhoea, muscular pains, eye infections and ophtalmias; and wounds due to venomous stings, etc.
As often in folk medicine plants have a symbolic clan value. This healing power is expected by Indigenous people but leaves modern pharmacologists confused.

As opposed to Polynesian they were regular drinkers of infusions and aqueous decoctions.
As many populations living close to nature, Indigenous Australians often employed fresh plants: sap, latex, leaves as well as young shoots and bark ground as plaster or in temporary application. For instance to cure mouth disorders and dental pains, people chewed leaves and spat the juice.

Indigenous Australians discovered the powerful physiological effect of nicotine.
There are indeed in Australian bushes some genera of Solanaceae, Duboisia and Nicotiana. The leaves of the small tree Duboisia hopwoodii were the most wanted leaves (to be differenciated from D. myoporoides and D. leichardtii containing rather other alcaloids, scopolamine or hyoscyamine, (see Datura)). People chewed leaves and later smoked them, as European people did.

Leaves and sprays were dried, ground and preserved with care in a very small bag (because good Duboisia is rare), or dried on fire and moistened and rolled like a cigar but after being blended with vegetable ash of special trees and sometimes with natural wax to better stick them together.
Chewing basic components of ash released nicotine of quid, thus increasing the sensation felt. The lime of betel quid in Asia or of coca in South America also helps release alcaloids.

Copyright 2006: Dr Jean-Michel Hurtel. All Reproduction Prohibited 		TOP