1.4 RESEARCH ON TRADITIONAL HERBS SHOULD REFER TO THEORIES AND CLINICAL APPLICATION OF TRADITIONAL MEDICINE
Many traditional herbs are clinically prescribed by practitioners of traditional medicine under the guidance of theories in traditional medicine, such as TCM in China and Ayurveda in India. This aspect has mostly been ignored by scientists in the field of modern research of herbal medicine for product development, particularly in Western countries. Even in Asia, chemists, biologists, and pharmacologists who have been studying herbal medicine with modern knowledge and technology in labs for many years rarely know enough about theories that guide the applications of herbal treatments in the clinic. One of the reasons is that such study is more challenging.
Traditional herbs might treat a disease in a way different from known modern drugs. Take TCM as an example. A disease can be divided into several “zhengs” based on TCM differentiation. “Zheng” is a Chinese word that is similar in meaning to English symptoms or signs. For example, there is “cold zheng,” “hot zheng,” “internal zheng,” “external zheng,” “excessive zheng,” “deficient zheng,” “yin zheng,” “yang zheng,” “damp zheng,” and “bi zheng” (bi means blocked). Different herbs may be used on different patients with same disease but different zhengs. Sometimes, no animal models can be found to match these zhengs for PD study of herbs that are clinically used for treatment of certain types of zhengs. Thus, a new model with a particular zheng has to be established first. To do this, scientists have to be knowledgeable in both traditional and modern medicines. Otherwise, the study results are not reliable. Up to now, Chinese scientists have found out the biological and pathological foundation for most of the zhengs in TCM and established many animal models for pharmacological study of herbal medicine.9
Theories of traditional medicines, such as TCM, cover etiology, pathology, diagnosis, and treatment. Study of these theories can not only help us to explore the mechanisms of herbal treatment, but also help scientists explore possible new etiology and pathology for diseases whose causes are still unknown in modern medicine, thus providing new directions for drug development. For such purposes, a variety of in vitro bioassays on different receptors, enzymes, and other targets and in vivo animal pharmacological tests should be performed on herbs—not only individual ones, but also herbal formulas.
For example, clinical practice has confirmed that Gui Zhi Fu Ling Wan (Cinnamomi and poria composition), a Chinese herbal formula composed of five Chinese herbs, is very effective in decreasing or eliminating uterine fibroids when their diameter is less than 5cm. This has been confirmed by comparing ultrasound exam results before and after the treatment in the clinic and by pharmacological study on rats. The uterine fibroids are usually removed by surgery in modern medicine if they cause severe abnormal bleeding or if they are too big. Quite often, the uterus will be removed together with the fibroids in order to prevent the regrowth of fibroids in the uterus at a later date. The Chinese formula can not only stop abnormal bleeding and decrease and eliminate the fibroid, but also prevent the regrowth of the fibroid because it regulates the imbalance of the hormones, the cause of fibroid growth. Female hormones, particularly estrogen and progesterone, are known to be related to stimulation of fibroids. TCM considers fibroid formation to be related to accumulation of stagnated blood (called “yu zheng”). Therefore, herbs that invigorate blood circulation are added to the formula. Combining the knowledge about formation of uterine fibroids in modern medicine and TCM, the mechanism of herbal treatment can be explained by chemical, biological, and pharmacological study. To study the treatment mechanism of the formula, not only in vitro assays and in vivo animal tests related to hormone regulation should be performed; those involved in blood circulation should also be carried out.
Research on traditional herbal medicine should be performed on the basis of clinical application and reference to the corresponding theories in each system. The main systems of traditional medicine from different countries will be briefly introduced in Section 1.5. TCM is mentioned below only as an example.
The application of traditional Chinese herbs is not as simple as Western drugs in that not all doctors prescribe the same medicines for the same disease. Quite often in TCM, one herbal formula consisting of several Chinese herbs (most often 5 to 15) is used for different diseases. On the other hand, one disease can be treated with different formulas by different doctors. For example, if an herb is unavailable, experienced Chinese doctors can easily modify a formula by replacing one or two herbs to give similar treatment results. This makes research scientists perplexed and frustrated because explanations by clinical doctors using terminology of TCM are sometimes difficult to understand. Due to the current meticulous division of research areas and a limited amount of energy, most scientists focus on indepth study in one field, and have no time to spend on other areas that are not closely related to their research. Even to those familiar with both TCM and modern science, if the knowledge on both sides is not extensive, it is still difficult for them to scientifically explain TCM theories with simple modern medicinal terms.
Many patients turn to TCM treatment after they have tried treatment with Western medicines with no effect. Chinese herbal formulas work better than Western drugs for many diseases, not only chronic ones caused by stress, but also on acute infections such as SARS and the H1N1 flu virus. However, research results show that effects of the components isolated from these herbs are mostly less than those of current Western drugs. Thus the question arises: Why or how are the effects of these formulas better?
According to the experimental results, the answer is definitely not the placebo
effect. The following might explain the reason.
1. Chinese herbs in a formula can work on different targets, that is, on different receptors and enzymes or other substances in the human body and stimulate the functions of nervous, circulatory, endocrine, immune, digestive, and other systems simultaneously. This is why TCM is a holistic medical system.
2. TCM emphasizes the protection of the digestive function as well as regulation of qi (pronounced “chee”) and blood (details about the definition and explanation of qi and the importance of regulation of qi and blood in TCM will be given in Chapter 10). TCM believes that a good digestive system will guarantee an effective supply of essential nutrients from foods to the human body. It also believes that blocked qi and blood circulation may cause hundreds of types of diseases. For treatment of chronic diseases with Chinese herbs, there are always herbs that improve blood circulation in the formulas; if the patient has a digestion problem together with other symptoms, herbs that regulate the digestive system are usually given first. These actually emphasize the importance of maintaining cell functions with enough nutrients and excluding metabolites in a timely manner through functional blood circulation.
Scientists are currently trying to find out the relationship of mutant genes as causes of diseases, such as Alzheimer’s and Parkinson’s. But what are the main causes of the gene mutations? According to TCM, I would propose that the main cause of such diseases or aging is probably poor capillary blood circulation, which can be caused not only by the fats we eat, but also by the accumulation of metabolites from cells or dead cells. My reasoning is based not only on the above TCM theories and my clinical application of Chinese herbs, but also on the confirmation that the disease of agerelated macular degeneration (AMD) is pathologically related to the accumulation of aging retina in the photoreceptor outer segment membrane,18 part of a research program I performed when I worked as a postdoctoral scientist in the group of Professor Koji Nakanishi from Columbia University. No doubt, further experimentation is required.
Soure: Traditional Herbal Medicine Research Methods, Edited by Willow J.H. Liu Copyright © 2011 John Wiley & Sons, Inc.
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