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Medical herbalism. Definition. Medical herbalism may be defined as the practice of using products in which all active ingredients are of herbal origin to treat the sick. In practice rather more detail is required. Definition. - PowerPoint PPT Presentation

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  • Medical herbalism

  • Definition Medical herbalism may be defined as the practice of using products in which all active ingredients are of herbal origin to treat the sick. In practice rather more detail is required.

  • Definition According to the World Health Organization (WHO) Guidelines, herbal medicines are considered to be: Plant-derived materials or products with therapeutic or other human health benefits which contain either raw or processed ingredients from one or more plants. In some traditions materials of inorganic or animal origin may also be present.

  • Definition The European Directive defines a herbal medicine thus: A substance or combination of substances of herbal origin presented for treating or preventing disease or with a view to making a medical diagnosis or to restoring, correcting or modifying physiological functions.

  • History The exact origins of herbalism are unknown. Probably it was several different groups of prehistoric peoples who discovered that some herbs were good to eat, whereas others had curative powers. Humans also discovered plants with peculiar, reality altering, stimulating and inebriating effects. In ancient cultures these were considered to be plants of the gods.

  • History The mechanism of action of herbs remained a mystery for centuries and in some cases still remains a mystery. Only the development of sophisticated techniques of chemical analysis in the last century has begun to provide some of the answers. The first medical records date from ancient Assyria, China, Egypt and India.

  • History William Turner was the first person to study plants scientifically in the sixteenth century. He travelled widely throughout Europe and grew plants in his gardens in south-west London (later the Royal Botanical Gardens, Kew).

  • History At this time the Doctrine of Similars determined how plants were used. It was promoted by Paracelsus (14931541). According to this paradigm every plant acted in effect as its own definition of its medical application, resembling either the part of the body afflicted or the cause of the affliction. Nicholas Culpepper (161654) was an influential proponent of the Doctrine of Signatures as well as various astrological theories, by which herbs were set under the domination of the sun, moon or one of the five planets then known. His herbal, published in 1652, was extremely successful, being reprinted many times.

  • History In America Samuel Thomson (17691843) used simple herbs for bodily correction. He was so successful that opposition from the medical profession was strong and uncompromising. His fame spread to England where, thanks to the promotion by a Mr George Lees, the Thomsonian system was embraced byMr Jesse Boot when he opened the first of what was to become the UKs biggest multiple pharmacy chain, in Goose Gate, Nottingham in 1872. Renewed interest in natural medicines has led to a resurgence of demand for herbal medicines in the last 20 years.

  • Theory Traditionally, the herbalist has recognised four clear stages when offering treatment for any particular condition, individualising the prescription according to holistic methodology to take account of their patients particular needs: 1. Cleansing the body. 2. Mobilising the circulation. 3. Stimulating digestion. 4. Nourishment and repair.

  • Theory 1. Cleansing the body: removal of toxins and other noxious influences real or imagined that might cause a physical or mental barrier to treatment. Diuretics, expectorants and laxatives are involved here. 2. Mobilising the circulation: traditionally disease was seen as a cold influence on the body and before any other treatment the body should be comforted by heating agents. Hot spices and pungent medicines (e.g. ginger) and more gentle warming medicines are available for this purpose.

  • Theory 3. Stimulating digestion: inappropriate or too much heat in the body manifests itself as fevers and inflammatory conditions. Thus, the so-called cooling medicines are those used to treat these circumstances, leading to improved digestion. Anti-inflammatories, antiallergics and sedatives are examples of therapeutic classes of drugs that fall into this category. 4. Nourishment and repair: in this phase the herbalist deals with the debility arising from disease in the body. The term tonic covers a wide range of medicines used to support the body. Examples include hawthorn (Crataegus oxycanthoides), milk thistle (Silybum marianus) and St Johns wort (Hypericum perforatum).

  • Sources of reference Materia medicaRepertoryThe British Herbal PharmacopoeiaThe American Herbal Pharmacopeia

  • Sources of reference Materia medica: a comprehensive list detailing the main characteristics and uses of medicines, e.g. Potters Cyclopaedia of Botanic Drugs Repertory: a comprehensive list of medical conditions with suggested medicines for treatment, e.g. Herbal Medicine by Miller and Murray

  • Sources of reference The British Herbal Pharmacopoeia gives identification and usage information as well as providing instructions on how medicines should be prepared and the British Herbal Compendium provides up-to-date summaries of the available scientific knowledge on medicinal plants The American Herbal Pharmacopeia (www.herbal-ahp.org) began developing qualitative and therapeutic monographs in 1994, and intends to produce 300 monographs on botanicals, including many of the ayurvedic, Chinese and western herbs most frequently used in the USA.

  • General types of medicinal herbs used Practitioners use medicinal plants with: powerful actions, e.g. liquid extracts of foxglove and belladonna, with substantial toxic riskintermediate actions, e.g. tinctures of arnica and khella, with some adverse drug reactions (ADRs) gentle actions, e.g. infusions of German camomile and peppermint with less risk of ADRs.

    In many instances conditions can be treated by drugs in each of the three groups, e.g. cardiac disease responds to foxglove in the powerful group, arnica in the intermediate group and hawthorn in the gentle group.

  • Examples of the therapeutic use of herbal remedies

  • Active constituents in herbal medicinesBittersThe hot medicinesResinsSaponinsTanninsVolatile oils

  • Active constituents in herbal medicines Bitters Traditionally these were used extensively to stimulate appetite (i.e. in the final fourth stage of the healing process outlined above). It is now thought that they will be effective only if a malnourished state exists. The bitter constituents simulate the bitter receptors in the taste buds at the back of the mouth and give rise to an increase in the psychic secretion of gastric juice. The most effective chemicals are the monoterpene secoiridoid glycosides of gentian. Other extracts that have been used as bitters include quassia, quinine (Cinchona) and strychnine (Nux vomica).

  • The hot medicinesThe three most commonly used hot medicines include black pepper (Piper nigrum), cayenne pepper (Capsicum) and ginger (Zingiber). They are used as metabolic stimulants, more specifically as a facilitating agent to accompany other herbs whose stimulatory activity may be augmented.

  • Resins The term resin is applied to the sticky water-insoluble substance of complex chemical nature often exuded by the plant, soon hardening to protect an injury. Resins are usually produced by the plant in ducts or cavities, but may also be found in special cells elsewhere, e.g. in elements of the heartwood of guaiacum and the internal cells of the male fern.

  • Resins The term may also be applied to that part of a plant that is soluble in ether or alcohol (e.g. guaiacum resin and kava resin). Resins are used as astringents and antiseptics of the mouth and throat and have also been applied to inflammatory conditions of the upper digestive tract.

  • Resins Propolis, a product collected by bees from resinous plants, is used in herbal medicine, although it is not strictly herbal in nature. The product is also used in homeopathy. A balsam (e.g. balsam of Peru and balsam of Tolu) is an oleoresin containing a high proportion of aromatic balsamic acid.

  • Saponins Saponins are glycosides that produce frothy aqueous solutions. Plants containing these compounds (e.g. Quillaia saponaria) have been used for centuries as gentle detergents. Decoctions of soapwort (Saponaria) have been used to wash and restore ancient fabrics. They also have haemolytic properties and when injected into the bloodstream are highly toxic. When taken by mouth saponins appear to be comparatively harmless.Sarsaparilla is rich in saponins but is widely used in the preparation of non-alcoholic drinks.

  • Saponins Two distinct types of saponins may be recognised. The steroidal saponins are of great pharmaceutical importance because of their relationship to compounds such as the sex hormones, cortisone and the cardiac glycosides. Some species of the yam (Dioscorea spp.) and potato (Solanum spp.) contain steroidal saponins.

  • Saponins The second group of saponins is known as the pentacyclic triterpenoid saponins. This includes quillaia bark and liquorice root (Glycyrrhiza). The former is used as an emulsifying agent, the latter as a flavouring agent, demulcent and mild expectorant.

  • Tannins This is not a specific phytochemical group but a name for a group of chemicals that have a particular characteristic. The term tannin was first applied by Seguin in 1796 to denote substances present in plant extracts that were able to combine with animal proteins in the hides, preventing putrefaction and converting them to leather. Most tannins have molecular masses (Mr) of about 10005000 and many are glycoside

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