- Generally, all herbs contain some essential oil (eo)
- Some species have a higher concentration of eo
- Eos have a strong, usually pleasant, odor
- Obtained predominantly by distillation
- Citrus eos are cold-pressed
- Eos generally occur in special cells or glands of the plant
Essential oils are made up of a variety of constituents that have varied effects on the body.
Some are antiseptic, e.g thymol - a substance found in thyme essential oil and used in mouthwashes and gargles.
Some reduce fever and inflammation, for example, those found in yarrow, chamomile Matricaria recutita and Anthemis nobilis, and peppermint.
Aromatherapy is the healing art employing essential oils for medicinal and relaxation purposes.
Bitter principles are non-poisonous substances. They generally have a strong, bitter, but not unpleasant taste. When taken before meals they stimulate the appetite by promoting the flow of the digestive fluids. They are generally used in the form of alcoholic extract, tinctures, or medicinal wines. Examples are those found in blessed thistle Cnicus benedictus, gentian Gentiana lutea, centaury Centaurium erythraea, and species of artemesia Artemesia spp. The most famous bitter, hops, is used in the production of beer and ale.
Bind albumen in the skin and mucous membranes. Form a watertight protective layer, resistant to disease. Promote rapid healing and formation of new tissue over wounds. Effective compress for bathing inflammations and swellings,gargle for sore throats, mouthwash for inflamed gums, and for diarrhea. Excessive doses can irritate the stomach wall and damage the liver. If a cold infusion is prepared, only a small proportion of tannins are absorbed.
Examples of herbs containing tannins are agrimony Agrimonia eupatoria, eyebright Euphrasia officinalis, walnut Juglans nigra, self heal Prunella vulgaris, and salad burnet Pimpinella saxifraga. Tannins are usually found in the bark of trunks and roots and occasionally in leaves.
All plants produce mucilaginous compounds from metabolic activity
Some plants have a higher concentration, making them useful to herbalists.
The mucilage is a sticky gel and it:
- forms a layer on the surface of mucous membranes
- soothes inflammations
- protects from invading irritants
- mild laxative action
- reduces undesirable fermentation in the intestines.
Examples are those found in marshmallow Althaea officinalis, borage, quince Pyrus cydonia, slippery elm Ulmus rubra, plantain Plantago major or lanceolata, and flaxseed (also called linseed).
Vitamins, Minerals and Trace Elements
- If the soil is deficient in one or several elements, the plants grown in this soil will be deficient. Generally, wild herbs and weeds grow where they can best extract their mineral requirements from the soil. Often ill health is caused by a lack of these vital substances; so include herbs and weeds in your daily diet whenever you can.
- Some vitamins and minerals are soluble in water and can be taken in the form of teas. Oatstraw Avena sativa is an excellent example. When simmered in water, oatstraw releases the mineral silica needed for healthy skin and hair. If oatstraw tea is used regularly over a few months, you will notice the results in healthier hair and nails.