《Optimizing new therapeutic discoveries from ethnomedical and.doc》由会员分享，可在线阅读，更多相关《Optimizing new therapeutic discoveries from ethnomedical and.doc（19页珍藏版）》请在三一文库上搜索。
1、Optimizing new therapeutic discoveries from ethnomedical and ethnobotanical data.Memory Elvin-LewisWashington University Department of BiologySt. Louis MO 63130INTRODUCTIONOnly a few years ago, old concepts hampered the acceptance of the use of herbal remedies as having any potential therapeutic val
2、ue. There were a variety of reasons why they were poorly understood and disregarded, and overall were viewed as having little potential value, considered unreliable, old fashioned, and if formulated as mixtures of plants, totally incomprehensible as to worth. Furthermore pharmaceutical companies loo
3、king for potent and unique compounds often applied high-throughput mechanistic methods to screen both random and ethnobotanical collections with total disregard for the valuable ethnomedical data accompanying certain specimens. Without matching to presumed bioreactivity their rate of discovery was d
4、isappointing and thus these results continued to discredit their significance. Also, up until recently clinical trials were poorly conducted, and often so biased as not to be reproducible outside the country of origin. Thus claims of efficacy continued to be anecdotal and thus circumspect. In the pa
5、st decade there has been a radical change in opinion regarding the worth of utilizing ethnomedical and ethnobotanical data for the discovery of new therapeutic agents. In part, this has been related to the increasing interest in utilizing these sources as the basis for alternative and complementary
6、approaches to medicine; a concept that only a few years ago would have been disregarded as having little value to serving the needs of global medicine. With rising health care costs, expanding populations with increased life spans on one hand, and the seriousness of emerging infections that are deci
7、mating others, it is appropriate to search for remedies that could have a greater cosmopolitan application. Currently, with support from both the World Health Organization, and in the United States, the National Institute of Health and particularly, the National Center for Complementary and Alternat
8、ive Medicine (NCCAM), serious attempts are being made to understand the basis for their mode of actions and their clinical efficacy. In definition, an herbal remedy may be traditionally or serendipitously derived, varying in formulation and preparation, often unreliable as to plant identification, a
9、nd depending upon its cultural source, infrequently validated as to efficacy. It may be prescribed by a healer of experience or of questionable skill, or used in self-medication. Generally most of these remedies have moderate potency and toxicity, and thus are not fast acting nor overtly dangerous.
10、They are, however, not inert and adverse reactions, or interactions with other medications can occur (Elvin-Lewis, 2001). Treatments do not necessarily depend upon one plant. Many involve using plants in a sequential manner, or in many traditional Asian formulations they carefully mixed for maximum
11、efficacy of each bioreactive ingredient. Today, many of these ancient remedies are being clinically evaluated, and modified for optimal efficacy. If bioreactive components are known, the plant or plants may be formulated or blended into standardized botanicals or phytopharmaceuticals. In these forms
12、 they are likely to contain several bioreactive components, which can act together to affect an optimal therapeutic response. With anti-infectives, for example, the risk of evolving resistance to the medication is lowered. Moreover, this form of combinational therapy, may elicit additive or synergis
13、tic effects that are not apparent when the bioreactive compounds are used independently from one another. Only rarely will any plant yield a compound low in toxicity, potent and unique enough to be worthy of becoming a pharmaceutical. There are many reasons why regional variations in herbal remedies
14、 using the same flora can occur, particularly since cultural differences often dictate how diagnosis and efficacy is determined. Much depends upon the origins of the medicinal systems that are being applied, as well as outside influences that are affecting both formulation and application. For examp
15、le, knowledge may be widespread within a population, known to only a few specialized healers through oral tradition, or applied by trained practitioners using well-documented formulations outlined in traditional pharmacopeias. Many pharmacopeias are constantly evolving, and those of current Western
16、origin may incorporate both traditional and novel uses of phytomedicines. Within this context, one can expect to find deviations in appropriate plant identification, nuances of formula preparation, dosage, and types of treatment regimens. The formulations are comprised of individual or mixed formula
17、tions of plant material and sometimes other products, used together or sequentially and are prepared to be used as infusions, decoctions, poultices and salves, eye, ear and nose drops, enemas, purgatives, suppositories, emetics, snuffs, vapor baths, inhalants, and injectibles etc. To determine how a
18、 particular remedy is impacting upon the health of its users, this type of expected variability needs to be understood. By accumulating sufficient data, general patterns of choice can become apparent that can allow the evolution of appropriate formulations and treatment regimens. Appropriate use of
19、a particular remedy may have a significant impact on the patterns of health care that are observed. However in the evolution of any new therapeutic agent, it is also important to establish its basis for bioreactivity and to conduct appropriate clinical evaluations based upon conventional (allopathic
20、) criteria. .When a specific disease can be related to its etiology, its clinical definition is apparent to both patients and practitioners, and clinical assay parameters are available to establish efficacy, patterns of change can be followed during treatment. Allopathic parameters can include modif
21、ications in clinical presentation, physiologic, serologic or other defined responses relative to the disease entity before, during and after treatment. Value is further confirmed by showing how a remedy affects degrees of incidence, that specific bioreactivities can be identified, dereplications aff
22、irm value, clinical evaluations have merit, and toxic or adverse effects are minimal. While definitions of resolution may vary among herbal practitioners, a well-defined response to therapy is an important factor if allopathic confirmation is to be obtained. Fitting remedies for these types of studi
23、es are Hepatitis B (Elvin-Lewis et al 2002, Elvin-Lewis, in manuscript) and diabetes (Lewis and Elvin-Lewis, 2003). Applying these techniques would be unsuitable when symptoms are vague and confusing, multiple etiologies are known, the disease is of minor importance, treatment regimens unclear, and
24、complex diagnostic procedures are required. When numerous bioreactive remedies for a disease make identifying the best for a region challenging then it is important to evoke a consensus of worth throughout a population by eliciting appropriate clinical data, and proof of efficacy from individuals us
25、ing the remedies, as well as practitioners that may be prescribing. This technique referred to as ethnomedical focusing avoids bias associated with limited interviews and provides a more accurate assessment of value. It is noteworthy, that uses within a family unit can vary, so depending on only a f
26、ew informants could skew the accuracy of the results. In my research this technique has been applied to chewing-stick use in Ghana Adu-tutu et al, 1979, Elvin-Lewis et al, 1980b) and tooth blackening (Elvin-Lewis, 1983; Lewis and Elvin-Lewis, 1984) and use of hepatitis remedies in Amazonia (Elvin-Le
27、wis et al 2002). It followed that the most popular remedies are generally the most bioreactive. Moreover, selective criteria are applied, and plant use can vary in the same region depending upon tribal or community preferences, age, gender, availability and the like.POLYETHNIC DERIVATION OF PHARMACO
28、PEIAS OF THE CARIBBEAN BASIN.Countries of the Caribbean Basin with their evolving polyethnic herbal medicines have the potential of contributing significantly to this effort primarily because so many types of traditional medicines have employed this regions unique flora. Empirical evaluations are no
29、t just of post Colombian origin but have been ongoing for over 500 years. While contributions of the original inhabitants of the Caribbean island nations are unknown, it is clear that both indigenous plant sources and those imported from elsewhere are being widely utilized for medicinal purposes. Th
30、is knowledge has not been necessarily exclusive to one group or another, and with the admixture of cultural approaches to healing has resulted in the development of pharmacopeias that deserve appropriate assessment as sources of new therapeutic agents whether they be eventually used as botanicals, p
31、hytopharmaceuticals or pharmaceuticals. To appreciate present-day medicinal practices within the Caribbean Basin it is important to recognize the contribution of these various medicinal systems (Elvin-Lewis, 2001). While several decades old, Mortons Atlas of Medicinal Plants of Middle America is suf
32、ficiently comprehensive to provide the basis for understanding the therapeutic uses of this regional flora (Morton 1981). Nowadays, national policies related to the collection and utilization of primary data within Caribbean countries may differ fundamentally from several decades ago when collection
33、 of information was obtained without fiduciary constraints. Within this context all laws and policies regarding bioprospecting activities to which the host country is a signature must be understood and applied to prevent the project being labeled as “biopiracy”. This is particularly true when indige
34、nous pharmacopeias are being explored. In this respect, it is important to engage oversight from national authorities and to employ a comprehensive scientific team and legal entities representing all parties, so that parameters of access are appropriately defined, collection of data and specimens ar
35、e optimally achieved, and equitable benefit sharing is officially evolved and appropriately understood. When evolution of commercial products is the goal, appropriate entities must be identified to make this possible, and renewable resource strategies well thought-out. EUROPEAN TRADITIONAL MEDICINEE
36、uropean traditional medicine has its origins in ancient Egypt, Assyrian, Greek, Arabian and Roman cultures. Many plant choices were the product of the concept of the Doctrine of Signatures. The plants appearance (e.g., shape, color) often determined its use in specific therapies. During the 19th cen
37、tury, formal types of herbalism in the form of both homeopathy and naturopathy evolved that are still practiced today. In addition, many herbalists undergo specified apprenticeships and belong to professional societies. Although regulatory standards for herbal drugs vary from country to country the
38、policies regarding their formulation and use continue to develop. The current pharmacopeias often appear in the form of monographs outlining parameters of formulation, use, efficacy and toxicity of each individual herb. The uses of phytopharmaceuticals standardized to bioreactivity levels are becomi
39、ng increasingly popular, and in Germany, appear in monographs that carefully outline parameters of use and safety. There, physicians may prescribe certain types. Currently new formulations may contain plants obtained from any where in the world. Self-medication is common (Elvin-Lewis, 2001).ASIAN TR
40、ADITIONAL MEDICAL SYSTEMS.Asian medical systems are based on a long tradition of use of pharmacopeias that appear in ancient texts. Practitioners are formally schooled, and generally adhere very closely to well-defined methods of diagnosis, formulation of drugs containing plants, sometimes, animal p
41、arts and minerals, and treatment regimens. In India, for example, practitioners of Aryuveda (Hindu), Unani (Arabic) and Siddha may work in the same medical centers with conventional allopathic physicians. Also in India, the regional “tribal” pharmacopeias are now being recognized as a valuable new r
42、esource of healing plants, and are being actively investigated for their value. Sometimes these medicinal plants are used as substitutes in traditional formulations. It is unclear if this “tribal” knowledge resides primarily with traditional healers or is generally known to a particular group. Howev
43、er when appropriately identified, policies are in place for appropriate benefit sharing should a commercially viable discovery be made.The medical systems of East Asia e.g., China (Wu-Hsing) and Japan (Kampo) are philosophically linked through commonalities in diagnosis, formulation and treatments.
44、In some instances, only slight variations in the concentration of components may exist as seen for hepatitis remedies used in China (Xiao Chai Hu Tang) and Japan (Sho-Saiko-To), respectively. Bioreactivities associated with plants used in these formulations denote complementary modes of action and s
45、everal are considered hepatoprotective, anti-inflammatory, immunostimulating, antiviral, antiemetic and antipyretic.Many of these Asian formulations represent complex mixtures of plants designed to optimize the value of the remedy, however accompanying packaging inserts may not describe all ingredie
46、nts or potential adverse effects. Unfortunately, undesirable reactions to traditional Asian formulations exist. Because of the lack of regulatory policies, advertent or inadvertent substitutions of ingredients can occur. Since the practitioner often formulates according to the patients needs, remedi
47、es bearing the same name may vary in content. This may be problematical if adverse reactions result. Disconcerting also is the inclusion of unapproved ingredients including potent pharmaceuticals, toxic and allergenic substances, and a number of heavy metals in concentrations of over 30 ppm. General
48、ly, when compared to pharmaceutically derived drugs, the incidence of life-threatening situations is significantly lower with most of these therapeutic remedies. However, until the time that appropriate regulatory practices are properly instituted so that drug content and treatments are standardized
49、, the meaning of well-designed clinical evaluations will remain circumspect. Unlike a few years ago when claims of efficacy could not be substantiated, suitable studies are beginning to be published that indicate that attempts are being made to overcome these difficulties. Moreover, the increased interaction of scientists studying these complementary Asian medicinal systems should be valuable in authenticating their cosmopolitan value (Elvin-