Native Healers. Anita Ralph

      Mucilage dripping from a plant.

      Medicinal plants containing significant quantities of mucilages include marshmallow, Althaea officinalis L.; comfrey, Symphytum officinale L.; linseed, Linum usitatissimum L.; psyllium seed, Plantago ovata Phil.; and slippery elm, Ulmus fulva Michx.

      Mucilages are graded by the ‘swelling index’, that is, by their ability to swell and increase their surface area.¹³ An alternative word would be gloop!

      In the picture above, we can see a perfect example of a mucilage produced from a plant. The Sierra Mixe maize has aerial roots, which produce large quantities of mucilage, which it gives to bacteria for food in return for nitrogen. This is a fine example of ‘gloop’.

      Linseed, also known as flax seed, and psyllium seed are often left in water to swell before drinking. The product can then coat and soothe the linings of the digestive system. These herbs tend to taste very mild, and pleasant. It is usually the texture that initially offends some people. However, they are a really great way to explore our sensory interaction with plants!

Tannins

      The term ‘tannin’ was first applied to substances present in plants able to combine with the proteins contained in animal hides, preventing their putrefaction and converting them into leather.

      Two main groups of tannins are usually recognised—hydrolysable and condensed.

      Hydrolysable tannins

      If something is hydrolysable, it means it can be broken down by water. Plants that contain large quantities of hydrolysable tannins are not suitable for use internally, nor are they suitable for use on open wounds.

      Condensed tannins

      Condensed tannins are so named because they are formed from a con-densation of molecules called flavans, related to the flavonoids, a group of compounds highly beneficial to health.⁸ Unlike hydrolysable tannins, condensed tannins cannot be broken down by water, and tend to form red, insoluble substances and are largely responsible for the brownish colour of so many herbal tinctures! There is little evidence of ill-effects and much evidence of benefit from condensed tannins, so they are considered suitable for both internal use, and for application to open wounds.

      One example of a very useful plant in the Rosaceae family is tormentil, Potentilla erecta (L.) Raeusch, which has condensed tannins in its reddish-brown roots. Tormentil was traditionally used to stop diarrhoea, and the positive effects of the tannins it contains are as follows:

      •Dries up excessive watery secretions

      •Heals digestive membranes

      •Increases resilience of membranes against invading infection

      •Potentially destroys invading organisms by their ability to precipi-tate proteins

      From the beneficial effects of tannins listed above it is easy to see how and why tannins have a strong history of use externally in the treatment of burns. When a tannin solution comes into contact with tissue it interacts with the tissue proteins to form a tough, leathery structure called an eschar. The formation of this eschar acts to seal the wound, thus preventing subsequent infection and allowing new tissue to form. Use of tannins for this purpose was practised during World War I, and was thought to be responsible for saving many lives.

      Recent research published in the Malawi Medical Journal in 2005 revisited this technique and concluded that;

      This study was not blinded. However, results of this pilot study suggest that the use of tannins may provide benefit by reducing colonisation of Staphylococcus aureus with better quality of healing and at the same time not increasing toxicity.

      —L. Chokotho and E. van Hasselt⁷

      (We would like to stress here that any serious burn should be treated by a healthcare professional as a matter of urgency.)

      It has been observed that some plants increase their production of tannins in response to grazing by animals. This causes the animals to move on, and not over-graze a particular tree or shrub. Interestingly, the response to produce more tannins also occurs simultaneously in neigh-bouring plants, suggesting that some communication between plants is happening and the plants are helping each other out!

      Many tannins have beneficial effects in small to moderate doses by sealing wounds and strengthening mucous membranes. Improvement to the resilience of any epithelial tissue will increase the immunity to infection there.¹¹ Taken in excess, tannins can inhibit nutrient absorption, so that excessive black tea consumption can lead to iron deficiency for this reason.

       Interesting Fact: Tea

      Incidentally, the plant in the UK we call ‘tea’ is in fact Camellia sinensis L. The word ‘tea’ actually refers to the method of preparation of an infusion or ‘tisane’.

      One traditional use of tannin-rich herbs is in mouthwashes to prevent or treat gum disease. Tannin-rich plants were traditionally used as snuff to treat nasal polyps. In barber's shops they were used to stop bleeding from shaving cuts.

      You may already be familiar with witch hazel water, prepared from the medicinal plant Hamamelis virginiana L. This distilled water can be applied externally to bruises, helping to seal up the internally broken blood vessels that lead to bleeding under the skin, as in a bruise. Witch hazel water has been a common first aid box ingredient for bruises and sprains. It is prepared from the leaf of the witch hazel tree, and contains hydrolysable tannins that should be used externally only, and on unbroken skin. The bark of witch hazel contains only condensed tannins, and can therefore be used internally.

      The sensation we associate with tannins is known as astringent, and the taste is described as Sour. Use of the word Sour with a capital S, suggests an energetic property. Western herbal medicine embraces modern science, but also honours the rational aspects of a more traditional or energetic approach.

      Note: Western herbal medicine perspective on ‘sour’ taste. Small amounts of Sour tasting herbs are traditionally considered to increase digestive vigour and tone. They stop the membranes of the body from becoming too flaccid or floppy, and by doing so improve function. They stop ‘leakage’ and loss of vital reserves or nutrients and increase resilience and dynamic strength. These are qualities observed by our forebears that can be explained today in more scientific terms—endothelial resilience.

Saponins

      Saponins are glycosides, characterised by their ability to produce frothy foam in water. Their molecular structure allows them to bind to water-soluble (hydrophilic) sugars at one end and fat-soluble (lipophilic) aglycones at the other end.

      Taken by mouth, they are relatively harmless, absorbed poorly from the gut following interaction with bacteria in the colon and are regularly consumed in everyday foods. Tomatoes, Solanum lycopersicum L. contain saponins as do many grains.

      Note: Plants in the Solanaceae (deadly nightshade) family, such as tomatoes, potatoes, peppers and chilli, contain a distinct sub-group of steroidal saponins known as steroidal-alkaloids that are possibly responsible for lowering plasma cholesterol concentrations.

      Medicinal herbs that contain beneficial saponins include sarsaparilla, Smilax ornata Lem., a medicinal herb from the Americas used in non-alcoholic beverages. It was, and still is, used as a therapeutically valuable and safe saponin containing plant.

      Saponins have a high molecular weight, and according to their structure are divided into two main groups: steroidal saponins (tetracyclic triterpenoids) and triterpenoid saponins (pentacyclic triterpenoids).

      The systemic effects of