Virtually all cultures have, throughout history, used a variety of plants or materials derived from plants for the prevention and treatment of disease. Evidence of the beneficial therapeutic effects of these medicinal herbs is seen in their continued use. Additionally, the development of modern chemistry permitted the isolation of chemicals from medicinal herbs that have served as drugs or starting materials for the synthesis of important drugs used today. Several modern drugs have been synthesized as a result of knowledge gained from studies of mechanisms of actions of chemicals first isolated from medicinal herbs. Thus, medicinal herbs have played a major role in the development of modern medicine and continue to be widely used in their original form. Whereas it is generally agreed that most medicinal herbs are safe under the conditions used, some are toxic and should be avoided even though they are readily available, and others have significant adverse side effects when misused.
Over the last decade, the consumption of medicinal plants has almost doubled in Western Europe. This trend is certain to continue, in view of the widespread interest in green medicine and the recent success of plant-derived drugs, such as the anticancer agent taxol and its derivatives, from Taxus baccata and T. brevifolia, and the antimalarial artemisin from the Chinese wormwood Artemisia annua.
Drugs of actuality:
Echinacea (Echinacea purpurea) is commonly used as a nonspecific immuno-stimulant, to treat cold, flu, bacterial and fungal infections, cancer, and arthritis. The popularity of this herb is assessed as a useful preventive agent in the therapeutic treatment for colds and influenza.
Garlic (Allium sativum) has thousands of years of medicinal use history and is marketed today as an antibiotic, antiviral, general tonic, and particularly for treating arterio-sclerosis, for reducing blood cholesterol levels and blood pressure.
Ginseng (Panax ginseng) is a venerable folk medicine typically used as a tonic or adaptogen, and an aphrodisiac. Clinical trials have yielded ambiguous results. Several scientists are very skeptical about its medicinal value and the quality of manufactured ginseng products, although they feel its use involves little risk.
Ginkgo (Ginkgo biloba) seeds, fruit and leaves have been used medicinally for almost 5.000 years. Today ginkgo leaf is used to treat Alzheimer's dementia, multi-infarct dementia, peripheral vascular disease, vertigo, and tinnitus. Ginkgo is also used to promote blood flow.
St. John's Wort (Hypericum perforatum) is an old-established medicinal plant. The oil was much used in the past in external treatment of wounds, burns, etc. Some time ago it was rediscovered and found to have quite special properties. It has been found that it has not only a sedative effect, but also specifically antidepressant properties.
I must mention several plants of the Greek flora:
Sage, Salvia fruticosa widely used in Greece, is an antiphlogistic, more especially for inflammation, of the mouth and throat. In addition to S. officinalis a monograph for S. fruticosa is scheduled to be prepared by the European Pharmacopoeia.
Thyme, Thymus capitatus. The dry leaves and flowers are used as a spice as a stimulant and antispasmodic against whooping cough.
Origanum dictamnus is known for its healing properties from the Antiquity. It is used in troubles of the stomach, of the digestive tract, in rheumatism, in arthritis and for gynecological troubles.
Origanum heracleotecum is used in infusion, as a stomachic, antispasmodic in cases of abdominal troubles of women, in respiratory catarrhs, in asthma, in urinary retention and in the form of gargles for the infection of the throat and the gums. It is also used as a spice in cooking.
The techniques used in the production of herbal products are the main topic related to modern Pharmacognosy
There is a tremendous range of sophistication in the processing of herbs-from crude herb to highly concentrated standardized extracts. Nonetheless, there are some common stages: collection/harvesting, drying, grinding, extraction, concentration, drying of extracts, and analytical methods.
Improvements of analytical methods have definitely led to improvements in harvesting schedules, cultivation techniques, storage, activity, stability of active compounds, and product purity. All these gains have resulted in tremendous improvements in the quality of herbal preparations now available.
The methods currently utilized in evaluating herbs and their extracts include organoleptic, microscopic, chemical, physical, and biological properties.
Organoleptic means the impression on the sense organs. Organoleptic analysis involves the application of sight, taste, touch, and occasionally even sound, to identify the plant.
Microscopic evaluation is indispensable in the initial identification of herbs, as well as in identifying small fragments of crude or powdered herbs, and in the detection of adulterants.
In crude plant evaluation, physical methods are often used to determine the solubility, specific gravity, melting point, water content, degree of fiber elasticity, and other physical characteristics.
Various chemical/physical methods are also used to determine the percentage of active principles (alkaloids, flavonoids, vitamins, essential oils), fats, protein, ash, acid-insoluble ash, or crude fiber present.
New sophisticated manufacturing processes. Supercritical fluid extraction is a method of major interest nowadays, with numerous advantages in the manufacturing process. Thus, we can eliminate undesired lipophilic compounds such as pesticides. If this new manufacturing process is applied to obtain new types of extracts, such extracts are very different from those of traditionally used ways. Hence, they constitute a new type of future generation plant extracts. For the moment, because the specific extracts represent a part of the whole plant with no traditional use, they must be considered as new products, requiring toxicological and clinical documentation.
Sophisticated techniques, such as high performance liquid chromatography and nuclear magnetic resonance, are often used to isolate out molecules and to identify chemically the constituents.
The plant or extract can be evaluated by various biological methods, mostly animal tests, to determine pharmacological activity, potency, and toxicity. Outstanding toxicological data on plant drugs have been published. Seven cases of acute cytotoxic hepatitis were found after the use of phytomedicines containing Teucrium chamaedrys. Commercial preparations containing T. chamaedrys have been removed from the market, and prescription preparations have been forbidden. Other cases have been observed in Belgium with a preparation of Chinese herbs, Magnolia officinalis and Stephania tetrandra contaminated by the toxic herb, Aristolochia fung chi.
Quality control guidelines based on methods described in pharmacopoeias from more than a dozen nations have been compiled in a recent document prepared by the World Health Organization (WHO).
A widely acknowledged system for the development of therapeutic monographs is that of the German Commission E. Commission E monographs are geared toward therapeutic information on each herb, its botanical and chemical constituents, pharmacological properties, pharmacokinetics and toxicology, as well as clinical information.
In parallel two European organisms have recently been instituted to normalize medicinal plants.
The general purpose of ESCOP (European Scientific Cooperative on Phytotherapy) is to develop a coordinated scientific framework, to promote the acceptance of phytomedicines, to support and initiate clinical and experimental research, and to improve international accumulation of scientific and practical knowledge. Its main objective is to establish criteria that will contribute to the acceptance of phytotherapy on a European level.
European Pharmacopoeia. The pharmacopoeia was created in 1963 and now represents 25 European countries. It consists of 16 groups of experts and has published more than 700 monographs. One of the main purposes of the Pharmacopoeia is to define assurance of the quality of the raw material. This is accomplished by describing control security, batch consistency, and batch safety. It employs analytical methods that are provided in the pharmacopoeia monograph, which consists of the definition, the characters, identification, and the assay.
We believe that Phytotherapy of this millenium will evaluate in the following way.
By developing the analytical bases of raw materials (drugs), applying old and new knowledge, establishing identity, purity and health parameters.
Providing compounds that would constitute new lead compounds as was previously done in the majority of known therapeutic groups; compounds which will show to be true tools for the study of different mechanisms of action the drugs.
By developing therapeutic validation using phytochemical-pharmacological knowledge of medicinal plants obtained from Ethnopharmacology, originating drugs with their own therapeutic identity which will be used alongside with synthetic drugs for the sanitary needs of the population.
An imaginative hope for the future may be concretely developed in two directions.
In terms of research - the constant discovery of new leader compounds gives rise to the industrial production of highly sophisticated molecules against severe pathologies.
In terms of public health - the development of our environmental resources for producing new products such as herbal remedies.
In each case, scientists and specialists from different disciplines need to develop a very close collaboration, because natural products are burdened by very specific and complex problems. A platform is needed to discuss these problems, to exchange experiences on the assessment of herbal drugs, and to create a special group facilitating mutual recognition.
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