such as for example azulene in German chamomile which is particularly applicable for the relief of inflamed and irritated conditions of the digestive tract, while those in dill relax spasm and colicky pain in the gut. Some oils have an expectorant action such as in thyme and hyssop, clearing mucous from the chest, while others are diuretic, useful for fluid retention and urinary infections. While they exert their beneficial effects on the physical body, they also reach the brain and nervous system and have a wide range of mento-emotional applications.
Fixed Oils
These are the lipids found in all plants, especially in the seeds, and they contain fatty acids which are either saturated, monounsaturated or polyunsaturated. They are vital for growth and health, the formation of cell membranes andthe healthy functioning of the immune and cardiovascular systems. Two fixed oils that exist in every cell, particularly in the nervous system, known as essential fatty acids, are linoleic (found in evening primrose oil, and saw palmetto berries), and linolenic acid (found in flax seed). These essential fatty acids are not able to be synthesised in the body and so need to be taken in through our diet. In the body linoleic acid is converted into gamma linolenic acid (GLA); atopic allergies such as eczema and asthma and other immune problems have been related to the lack of the enzyme responsible for this conversion in some individuals. Evening primrose oil contains GLA and for this reason is very useful for treating such problems.
Polysaccharides
These large sugar molecules are found widely in the plant world, for example in fructose, glucose, and cellulose, and consist of chains of sugars linked to other molecules. They include mucilage, gums, and fructans. Some polysaccharides, particularly beta-glucans found in, for example, reishi and shiitaki mushrooms, have immune-stimulating properties. They achieve this through throughactivating cytokines which enhance the production of white blood cells and antibodies, and with their anti-inflammatory and anti-tumour properties. Liquorice, codonopsis, aloe vera, rehmania and cinnamon also contain immune-stimulating polysaccharides.
Mucilage
This is a sugary, gel-like substance with the ability to draw water to it to form as viscous fluid. When taken orally, mucilage coats the mucous membranes of the digestive, respiratory and genito-urinary tracts and protects them from irritation and inflammation. Herbs rich in mucilage including slippery elm, marshmallow and plantain are prescribed for their cooling and soothing properties. They can relieve diarrhoea by reducing peristalsis caused by irritation of the gut lining, but can also be used as laxatives as they absorb water into the bowel and bulk out the stool, e.g. psyllium seeds.
Aloe Barbadensis, or aloe vera, contains polysaccharides, which stimulate the immune system.
Gums
These are protective and healing exudates composed of monosaccharides which are released when a plant is damaged. Those in guggulu enhance the liver's metabolism of cholesterol by promoting the uptake of LDL cholesterol from the blood (Tillotson, 2001). Marigold is high in gums with antimicrobial, antifungal and anti-inflammatory effects.
Fructans
These are composed of fructose and occur especially in the Asteraceae family as inulin. Herbs rich in inulin include elecampane, globe artichoke, goldenrod, gentian, codonopsis and burdock. Inulin helps regulate blood sugar and enhances the immune system by acting as a prebiotic to nourish the beneficial flora in the gut.
Calendula officinalis, or marigold, is high in gums.
Alkaloids
A diverse group of chemicals that contain a nitrogen-bearing molecule and are pharmacologically very potent. Many of the more toxic plants contain alkaloids, such as atropine in belladonna and morphine from the opium poppy, the first alkaloid to be isolated in 1806 (Tillotson, 2001). Caffeine, ephedrine, quinine, strychnine, piperine, nicotine and codeine are all alkaloids with diverse actions, ranging from stimulants, bronchodilators, antimicrobials and anti-inflammatories, to narcotics and painkillers.
Sources
Pengelly, A. (2004), The Constituents of Medicinal Plants. Oxford: CABI Publishing.
Huang, K. (1993), The Pharmacology of Chinese Herbs. Boca Raton: CRC Press.
Tillotson, A. K., et al (2001), The One Earth Herbal Sourcebook. New York: Kensington Publishing Corps.
Medicinal Actions of Herbs
The following guide classifies herbs according to their medicinal action (see the Materia Medica, pages 93-275).
Alteratives
Barberry, Bladderwrack, Blessed thistle, Blue flag, Burdock, Cleavers, Dandelion, Devils claw, Elderflower, Eyebright, Echinacea, Garlic, Wild lettuce, Golden seal, Gotu cola, Liquorice, Marshmallow, Nettles, Oregon grape root, Poke root, Red clover, Sarsaparilla, St John's wort, Uva ursi.
Analgesic/Anodyne
Chamomile, Hops, Passion flower, Poppy, Skullcap, St John's wort, Valerian.
Anthelmintic
Aloe, Black walnut, Garlic, Senna, Thyme, Wormwood.
Antibilious
Barberry, Dandelion, Golden seal, Mugwort, Vervain, Wild yam, Wormwood.
Anticatarrhal
Bearberry, Boneset, Cayenne, Elder, Elecampane, Eyebright, Garlic, Golden seal, Goldenrod, Hyssop, Marshmallow, Mullein, Sage, Thyme, Yarrow.
Anti-emetic
Lemon balm, Cayenne, Dill, Fennel, Lavender, Meadowsweet.
Anti-inflammatory
Chamomile, Devil's claw, Frankincense, Liquorice, Ginger, Marigold, St. John's wort, Witch hazel, Turmeric.
Anti-lithic
Bearberry, Corn silk, Couch grass, Gravel root.
Anti-microbial
Bearberry, Cayenne, Clove, Coriander, Echinacea, Elecampane, Garlic, Liquorice, Marigold, Myrrh, Peppermint, Rosemary, Sage, St John's wort, Thyme, Wormwood.
Anti-spasmodic
Black haw, Black cohosh, Chamomile, Cramp bark, Lime blossom, Mistletoe, Motherwort, Pasque flower, Skullcap, Thyme, Valerian, Vervain, Wild yam.
Aperient (See Laxative).
Aromatic
Chinese angelica, Cardamom, Celery, Chamomile, Cinnamon, Coleus, Coriander, Dill, Fennel, Hyssop, Ginger, Meadowsweet, Peppermint, Rosemary, Valerian, Wood betony.
Astringent
Agrimony, Bayberry, Bearberry, Beth root, Bistort, Cramp bark, Elecampane, Eyebright, Goldenrod, Ground ivy, Meadowsweet, Mullein, Myrrh, Raspberry, Rosemary, Sage, Vervain, Witch hazel Leaf.
Bitter
Barberry, Dandelion root, Devil's claw, Globe artichoke, Golden seal, Hops, Polygonum multiflorum, Qing hao, White horehound, Wood betony, Wormwood, Yarrow.
Cardiotonic
Astragalus, Coleus, Hawthorn, Motherwort.
Carminative
Angelica root, Cayenne, Chamomile, Cinnamon, Dill, Fennel, Ginger, Hyssop, Lavender, Lemon balm, Peppermint,