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Herbal medicine

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Dioscorides’ Materia Medica, c. 1334 copy in Arabic, describes medicinal features of cumin and dill.

Herbalism, also known as herbal medicine, herbology, and phytotherapy, is a folk and traditional medicinal practice based on the use of plants and plant extracts.

Utilizing the healing properties of plants is an ancient practice. People in all continents have long used hundreds, if not thousands, of indigenous plants for treatment of various ailments dating back to prehistory. These plants are still widely used in ethnomedicine around the world.

The first generally accepted use of plants as healing agents were depicted in the cave paintings discovered in the Lascaux caves in France, which have been Radiocarbon dated to between 13,000 - 25,000 BCE.

Anthropologists theorize that over time, and with trial and error, a small base of knowledge would have been acquired within early tribal communities. As this knowledge base expanded over the generations, the specialized role of the herbalist emerged. The process would likely have occurred in varying manners within a wide diversity of cultures.

Plants have an almost limitless ability to synthesize aromatic substances, most of which are phenols or their oxygen-substituted derivatives such as tannins. Most are secondary metabolites, of which at least 12,000 have been isolated, a number estimated to be less than 10% of the total. In many cases, these substances (esp. alkaloids) serve as plant defense mechanisms against predation by microorganisms, insects, and herbivores. Many of the herbs and spices used by humans to season food yield useful medicinal compounds.

The use of and search for drugs and dietary supplements derived from plants have accelerated in recent years. Pharmacologists, microbiologists, botanists, and natural-products chemists are combing the Earth for phytochemicals and leads that could be developed for treatment of various diseases. In fact, many modern drugs have been derived from plants.

The use of herbs to treat disease is almost universal among non-industrialized societies. A number of traditions came to dominate the practice of herbal medicine in the Western world at the end of the twentieth century:

Many of the pharmaceuticals currently available to Western physicians have a long history of use as herbal remedies, including opium, aspirin, digitalis, and quinine.

Biological background

All plants produce chemical compounds as part of their normal metabolic activities. These can be split into primary metabolites, such as sugars and fats, found in all plants, and secondary metabolites found in a smaller range of plants, some only in a particular genus or species.

The autologous functions of secondary metabolites are varied. For example, as toxins to deter predation, or to attract insects for pollination. It is these secondary metabolites which can have therapeutic actions in humans and which can be refined to produce drugs. Some examples are inulin from the roots of dahlias, quinine from the cinchona, morphine and codeine from the poppy, and digoxin from the foxglove, and salicylic acid alpha-hydroxybenzoic acid, C6H4(OH)(COOH). S.A. led to the development of Aspirin, acetyl-salicylic acid, originally a trade name, patented by Bayer.

In 2004 the National Center for Complementary and Alternative Medicine began funding clinical trials into the effectiveness of herbal medicine.[1]

Surveys of a scientific approach to herbal medicine can be found in the books Evidence-based herbal medicine,[2] and Herbal and traditional medicine: molecular aspects of health.[3]

Popularity

A survey released in May 2004[4] by the National Center for Complementary and Alternative Medicine focused on who used complementary and alternative medicines (CAM), what was used, and why it was used. The survey was limited to adults age 18 years and over during 2002 living in the United States. According to this survey, herbal therapy, or use of natural products other than vitamins and minerals, was the most commonly used CAM therapy (18.9%)[5] when all use of prayer was excluded.

Herbal remedies are most common in Europe. In Germany, the term apothecary (Apotheke) is still used, and next to prescription drugs one can order essential oils, herbal extracts, or herbal teas. It is even seen as a preferred treatment over the unnecessary overuse of industrialized production of chemical medication.

In the United Kingdom, the training of medical herbalists is undertaken in private colleges. Recently, Bachelor of Science degrees in herbal medicine are offered at Universities such as Middlesex University, University of Central Lancashire, University of Westminster and Napier University in Edinburgh.

At UCLAN the training of medical herbalists is extensive, and involves the study of anatomy, physiology, biochemistry, pathology, differential diagnosis etc. This enables the herbalist to be able to talk on equal terms with conventional medical practitioners. They learn about when they can treat, and when they should refer. They study the biochemistry of the body and the chemistry and structure of plants. Alongside this, they study traditional herbal medicine: Indications and Actions, and Energetics. They learn to recognise where conventional medical opinion diverges from traditional herbal medicine doctrine. They look at lots of different models for health care. A significant amount of self reflection is required (see http://www.uclan.ac.uk/courses/ug/bsc_hm.htm and http://www.medicalherbalist.eu). A medical herbalist is trained to view a situation from multiple perspectives in a non-dogmatic way.

Types of herbal medicine

Medicinal plants can be used by anyone, for example as part of a salad, an herbal tea or supplement, although some herbs considered dangerous are restricted from sale to the public. Sometimes such herbs are provided to professional herbalists by specialist companies. Many herbalists, both professional and amateur, often grow or wildcraft their own herbs. Many common weeds have medicinal properties (e.g. dandelion).

Medicinal herbs can be used in various forms:

Herbal teas

Main article: Tisane

There are two methods of making herbal teas, infusion and decoction. Infusion is steeping lighter parts of the plant (leaves, flowers, light stems) in boiled water for several minutes. Decoction is boiling tougher parts, such as roots or bark for a longer period of time. Herbal teas are often used as a home remedy, and as an alternative to tea and coffee.

Some popular herbal teas include borage, chamomile, dandelion, elderflower, hibiscus, nettle, and various species of mint. Each herb has unique medicinal properties, and a range of secondary effects; and this is linked to its use as a casual drink. For instance, Borage can be used medicinally (amongst other things) as an aid against depression; and it may be drunk more casually to lift the spirits. It was traditionally served as a pep drink for weary travellers. Secondary effects include use as an anti-inflammatory or balsam; and hormonal and metabolic regulation. Other herbs may have similar side-effects, but in different proportions and are used in different ways.

Mixing Herbs. To counteract the various complications and side-effects of an ailment, or to produce a more rounded taste, a number of herbs may be mixed, and formulas are the preferred method of giving herbs by professional herbalists. A well-known mixture used against a cold includes eucalyptus leaf, mint leaf (which contains Menthol) and juniper berry. Another is the age-old favourite "dandelion and burdock", from which the popular fizzy drink was derived.

Fresh or Dried? Many flower and leaf herbs lose volatile compounds within a few hours, as the juices and oils evaporate, the scent leaks away, and the chemicals change their form. Drying concentrates other compounds as water is removed. Most herbal traditions use dried material and the reported effects for each herb tend to be based upon dried herbs unless otherwise specified.

If you are using fresh herbs, you will need more of them, and the tea will have a somewhat different effect. Finely chop the leaf immediately before using it.

Generic Western Tea is usually the leaf of one specific plant, Camelia Sinensis, which grows mainly in India and China. It can be seen as just one of many herbal teas. It is a stimulant, and its main property is to increase alertness, along with a slightly sedative or calming effect. But unlike a fresh herbal tea, it may include artificial additives to enhance the taste and to preserve it in the shops. More expensive recipes include Darjeeling (from Darjeeling in India) and Earl Grey (which has bergamot added).

Infusion Methods. Some simple methods include -

  • Drop the herb directly into the water, steep and drink, including the chopped leaves.
  • Use a tea strainer which fits over the top of a cup.
  • Use a tea strainer which can be lowered into a teapot.
  • Cut the top off a normal teabag and empty it; replace the contents with your herb; fold over the top and staple it closed - then use it as normal teabag.

With all of these methods, let stand, covered, for at least 15 minutes to get medicinal benefits.

Coffee

Coffee is prepared by roasting and then grinding up the ingredients, or sometimes by decoction. It is normally stored as a powder or as granules. This is dropped directly into the hot water. Some preparations dissolve completely, while others remain partly solid, giving the drink a gritty texture.

Where the coffee remains gritty, it must be left to infuse before drinking. To avoid the gritty texture, a machine such as a coffee percolator or French press may be used.

Generic Western Coffee is the roasted seeds of either Coffea arabica or Coffea canephora. Its properties are similar to the generic tea plant Camelia Sinensis, but it has about twice as much caffeine, a richer, mellower taste, and different additives. The roasting process eliminates caffeine, and (like tea) the darker the coffee, the less caffeine it contains. When coffee is scarce, people often drink coffee substitutes.

Herbal teas include many of the coffee substitutes, and others; but they are used here for a wide range of properties, rather than merely to simulate the taste of coffee.

(article requires examples quoting properties, eg. dandelion root)

Herbal tinctures

Steeping a medicinal plant in alcohol extracts the alcohol-soluble principles into a liquid form that can be stored for long periods. Herbalists may mix several herbal tinctures to form an individualized prescription for each patient. Plant tinctures are also the basis for many homeopathic medicines.

Fluid extracts

Fluid extracts are stronger than herbal tinctures, and can be made with alcohol or glycerin. They are just highly concentrated tinctures, made by distilling off some of the alcohol used in the tincture process. The final result is a liquid plant compound that is roughly 40 times more potent than a tincture.

Solid extracts

Solid extracts are made from tinctures just like fluid extracts, but the entire solvent is separated from the plant compound, leaving a soft paste-like solid exract or a dry solid extract that is 400 times more potent than tinctures. Solid extracts can be diluted back to either fluid extracts or tinctures.

Herbal poultices

Poultices are a solid, vegetable fat-based mixture used externally. They have the shortest life span of any herbal remedy and must be made fresh for every use.

Powdered herbs and tablets

Herbs that are dried and (sometimes) certain parts are separated out then diced to powder fine consistency. Powered matter can then be compressed or put in an empty pill coating to form a tablet.

Herbal ointments

An ointment or salve is a semi-solid preparation made to be applied to the skin. Depending on the purpose for which it is designed and its method of preparation, the texture can vary from very greasy to a thick paste. The simplest ointments use petroleum jelly as a base. In traditional ointments, a combination of carrier oils is used that helps them to be absorbed through the skin, plus hardening agents to create the desired texture.

Essential oils

Main articles: Essential oil and Aromatherapy

Extraction of volatile liquid plant materials and other aromatic compounds from plants gives essential oils. These plant oils may be used internally in some forms of herbal medicine as well as in aromatherapy and generally for their perfume, although their medicinal use as a natural treatment (alternative medicine) has proved highly efficacious in the treatment of headache and muscle pain[6], joint pain[7] and certain skin diseases[8]

Herbal supplements

Herbal supplements tend to be commercial products in tablet or capsule form manufactured and marketed by the health food industry for sale in retail outlets to the general public, although there are some types that are sold only to healthcare practitioners for prescription. Herbal supplements are often standardized to contain stated levels of active phytochemicals. Some herbalists may not agree with the standardization of active ingredients, preferring instead to use the whole plant.

Examples of herbal medicine

Main article: List of medicinal herbs

There are hundreds of herbal remedies. An experienced practitioner can offer a comprehensive holistic approach to health. Examples of some commonly used herbal medicines:

Risks and benefits

A common misconception about herbalism and the use of 'natural' products in general, is that 'natural' equals safe. However many plants have chemical defence mechanisms against predators that can have adverse or lethal effects on humans. Examples are poison hemlock and nightshade, which can be deadly, although they are not sold as herbs. Herbs can also have undesirable side-effects just as pharmaceutical products can. These problems are exacerbated by lack of control over dosage and purity. Furthermore, if given in conjunction with drugs, there is danger of 'summation', where the herb and the drug have similar actions and add together to make an 'overdose'. In animals, there are other dangers. There may be residues in food from farm animals (e.g. eggs, milk, meat) or danger of 'doping' in competition animals. The latter may also apply to human athletes.

There is a danger that herbal remedies will be used in place of other medical treatments which have been scientifically tested for safety and efficacy, resulting in the development or worsening of a medical condition which could have been better prevented or treated. There is also a danger that an herbal remedy may itself cause harm which is unanticipated due to a lack of a full understanding of its composition and biochemical effects.

However, if a qualified Medical Herbalist, is consulted, he or she will have the required knowledge to prescribe and dispense herbs tailored to the individual, taking into account their medical history and any other medication. A qualified Herbalist will have studied for four years and passed exams in botanical and medical subjects, and will be a member of one of the profession's governing bodies. These include The College of Phytotherapy Practitioners and The National Institute of Medical Herbalists.

Forthcoming changes to laws regulating Herbal products in the UK, will ensure the quality of herbal products used. Most Medical Herbalists will be using herbal products from a supplier who already meets these standards.


Effectiveness

As noted above, there have been scientific studies which show that certain plant products can cure or prevent certain diseases. The gold standard for pharmaceutical testing is repeated, large-scale, randomized, double-blind tests. Some plant products or pharmaceutical drugs derived from them are incorporated into mainstream medicine. To recoup the considerable costs of testing to the regulatory standards, the substances are patented by pharmaceutical companies and sold for high profit. Pharmaceutical firms argue that the regulations protect public safety. Cynics point out that they have a secondary effect of setting a high financial barrier to competition.

Most herbal traditions have accumulated knowledge without modern scientific controls to distinguish between the placebo effect, the body's natural ability to heal itself, and the actual benefits of the herbs themselves. Many herbs have shown positive results in in-vitro, animal model or small-scale clinical tests. The few randomized, double-blind tests that receive attention in mainstream medical publications are often questioned on methodological grounds or interpretation. Studies tend to carry more weight if they are performed in the same country as the medical scientists evaluating them. Likewise, studies published in wide circulation magazines such as JAMA receive more consideration than those published in specialized herbal journals. Fortunately there is now much scientific research into the action and effectiveness of herbal remedies and many are justifying their traditional use. High quality trials involving proper controls and double blind methods are being increasingly carried out, with many useful results.

Herbalists tend to use parts of plants, such as the roots or leaves but not isolate particular phytochemicals. They argue that the synergy of the combined substances enhances the efficacy and dilutes toxicity. Western medicine on the other hand prefers single ingredients on the grounds that dosage can be more easily quantified. Dosage is in general an outstanding issue for herbal treatments: while most conventional medicines are heavily tested to determine the most effective and safest dosages (especially in relation to things like body weight, drug interactions, etc.), there are few established dosage standards for various herbal treatments on the market. Furthermore, herbal medicines taken in whole form cannot generally guarantee a consistent dosage or drug quality (since certain samples may contain more or less of a given active ingredient).

The issue of regulation is an area of continuing controversy in the EU and USA. On one end of the spectrum, some herbalists and consumers maintain that traditional remedies that have a long history of use do not require the level of safety testing as xenobiotics or single ingredients in an artificially concentrated form. On the other hand, others are in favor of legally enforced quality standards, safety testing and prescription by a qualified practitioner. Some professional herbalist organizations have made statements calling for a category of regulation for herbal products. Yet others agree with the need for more quality testing but believe it can be managed through reputation without government intervention. Clearly the full debate involves issues of politics, economics and the role of government that are beyond the scope of this article.

Name confusion

The common names of herbs (folk taxonomy) may not reflect differences in scientific taxonomy, and the same (or a very similar) common name might group together different plant species with different effects. For example, in 1993 in Belgium, in a formula created by medical doctors including someTCM herbs for weight loss, one herb (Stephania tetrandra) was swapped for another (Aristolochia fangchi) whose name in Chinese was extremely similar but which contained higher levels of a renal toxin, aristolochic acid; this quid pro quo resulted in 105 cases of kidney damage. Note that neither herb used in a TCMcontext would be used for weight loss or given for long periods of time. In Chinese medicine these herbs are used for certain forms of acute arthritis and edema. [19] [20] [21]

Standards and quality control

The legal status of herbal ingredients varies by country. For example, Ayurvedic herbal products may contain levels of heavy metals that are considered unsafe in the U.S., but heavy metals are considered therapeutic in Ayurvedic medicine.

In the United States, most herbal remedies are regulated as dietary supplements. Many herbs for home use could also be grown in a small home garden.

In the UK, herbal remedies that are bought over the counter are regualted as supplements,as in the US. However, herbal remedies prescribed and dispensed by a qualified Medical Herbalist, after a personal consultation, are regualted as medicines. A Medical Herbalist can prescribe some herbs which are not available over the counter, covered by Schedule III of the Medicines Act, for example.

Medical interaction

In consultation with a physician, usage of herbal remedies should be clarified, as some herbal remedies have the potential to cause adverse drug interactions when used in combination with various prescription and over-the-counter pharmaceuticals. Dangerously low blood pressure may result from the combination of an herbal remedy that lowers blood pressure together with prescription medicine that has the same effect. In particular, many herbs should be avoided during pregnancy.[22] However, most herbal books alert the reader to necessary precautions.

Not all physicians may be familiar with the effects of different types of herbal medicine, but general practitioners should be able to refer patients to a specialist, or investigate the medical literature on their behalf. A qualified Medical Herbalist, however, will be familiar with most commonly used medical drugs and their modes of action and therefore will only prescribe herbal remedies which will not interfere with these.

See also

References

  1. ^ NIH Institute and Center Resources, National Institute of Health.
  2. ^ "Evidence-based herbal medicine" edited by Michael Rotblatt, Irwin Ziment; Philadelphia: Hanley & Belfus, 2002
  3. ^ "Herbal and traditional medicine: molecular aspects of health", edited by Lester Packer, Choon Nam Ong, Barry Halliwell; New York: Marcel Dekker, 2004.
  4. ^ More Than One-Third of U.S. Adults Use Complementary and Alternative Medicine Press release, May 27, 2004. National Center for Complementary and Alternative Medicine
  5. ^ Barnes, P M (2004-05-27). "Complementary and Alternative Medicine Use Among Adults: United States, 2002" (PDF). Advance data from vital and health statistics; no 343. National Center for Health Statistics. 2004. p. 20. {{cite web}}: Cite has empty unknown parameter: |month= (help); Unknown parameter |accessmonthday= ignored (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help); Unknown parameter |coauthors= ignored (|author= suggested) (help) (See table 1 on page 8).
  6. ^ "Herbal Alternatives to Drugs in Pain Management, Part II". 2006. {{cite web}}: Text "author:John K. Chen, PhD, PharmD, OMD, LAc" ignored (help)
  7. ^ S. Y. MILLS, R. K. JACOBY, M. CHACKSFIELD and M. WILLOUGHBY (2006). "EFFECT OF A PROPRIETARY HERBAL MEDICINE ON THE RELIEF OF CHRONIC ARTHRITIC PAIN: A DOUBLE-BLIND STUDY". {{cite web}}: Unknown parameter |accessmonthday= ignored (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help)CS1 maint: multiple names: authors list (link)
  8. ^ White, H (2006-10-22). "Herbal Medicine and wart removal, hemorrhoids treatment and herpes prevention - without drugs: Canada, 2006". doc 102. various. {{cite web}}: Cite has empty unknown parameter: |month= (help); Unknown parameter |accessmonthday= ignored (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
  9. ^ Thompson Coon JS, Ernst E. "Herbs for serum cholesterol reduction: a systematic view." J Fam Pract. 2003 Jun;52(6):468-78. PMID 12791229
  10. ^ Kronenberg F, Fugh-Berman A. "Complementary and alternative medicine for menopausal symptoms: a review of randomized, controlled trials." Ann Intern Med. 2002 Nov 19;137(10):805-13. PMID 12435217 annals.org (133 K PDF file) Full text article
  11. ^ Block KI, Mead MN. "Immune system effects of echinacea, ginseng, and astragalus: a review." Integr Cancer Ther. 2003 Sep;2(3):247-67. PMID 15035888
  12. ^ www.herbaled.org Garlic
  13. ^ Ganzera M, Aberham A, Stuppner H. Development and validation of an HPLC/UV/MS method for simultaneous determination of 18 preservatives in grapefruit seed extract. Institute of Pharmacy, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria. J Agric Food Chem. 2006 May 31;54(11):3768-72. PMID 16719494
  14. ^ Takeoka, G., Dao, L., Wong, R.Y., Lundin, R., Mahoney N. Identification of benzethonium chloride in commercial grapefruit seed extracts. J Agric Food Chem. 2001 49(7):3316–20. PMID 11453769
  15. ^ von Woedtke, T., Schlüter, B., Pflegel, P., Lindequist, U.; Jülich, W.-D. Aspects of the antimicrobial efficacy of grapefruit seed extract and its relation to preservative substances contained. Pharmazie 1999 54:452–456. PMID 10399191
  16. ^ Sakamoto, S., Sato, K., Maitani, T., Yamada, T. Analysis of components in natural food additive “grapefruit seed extract” by HPLC and LC/MS. Bull. Natl. Inst. Health Sci. 1996, 114:38–42. PMID 9037863
  17. ^ Takeoka, G.R., Dao, L.T., Wong, R.Y., Harden L.A. Identification of benzalkonium chloride in commercial grapefruit seed extracts. J Agric Food Chem. 2005 53(19):7630–6. PMID 16159196
  18. ^ Gupta RK, Moller HJ. "St. John's Wort. An option for the primary care treatment of depressive patients?" Eur Arch Psychiatry Clin Neurosci. 2003 Jun;253(3):140-8. PMID 12904978
  19. ^ Dan Bensky, Steven Clavey, Erich Stoger, and Andrew Gamble. Chinese Herbal Medicine: Materia Medica, Third Edition. 2004: 1054-1055
  20. ^ Vanherweghem JL, Depierreux M, Tielemans C, et al. "Rapidly progressive interstitial renal fibrosis in young women: association with slimming regimen including Chinese herbs." Lancet. 1993 Feb 13;341(8842):387-91.
  21. ^ Vanhaelen M, Vanhaelen-Fastre R, But P, Vanherweghem JL. "Identification of aristolochic acid in Chinese herbs." Lancet. 1994 Jan 15;343(8890):174. PMID 7904018
  22. ^ gaiagarden.com Herbs to avoid during pregnancy

Regulation

Neutral

Criticism

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