LEUNG'S
(CHINESE) HERB NEWS
Number 35
November/December 2001

Herbs in this issue:

Aloe vera

Tufuling (Smilax glabra)

 

A Note From Dr. Leung

 

      This is not the first time I have spoken out about the poor quality of research in natural therapeutics and its related literature.  In fact, over the past 5 years, this topic has appeared repeatedly in this Newsletter.  I strongly believe the major cause of this poor quality is the failure of researchers, authors, editors, journal reviewers, abstractors, indexers, and others to recognize the impact of poorly defined or undefined natural products used in the research or described in a report.  Consequently, no matter how well designed a study is, if the product being studied is not precisely defined, the results can not be reproduced by others, which means they are worthless.  For example, if you were going to study aloe vera and you did not know what the aloe vera was (was it the dried bitter latex or the dried gel, or the so-called ‘pure aloe vera’ with mostly carriers?), you might as well go to a health food store and pick out any product labeled as ‘aloe’ or ‘aloe vera’ from its shelf.  This topic appears to be so straightforward, yet time and again I have come across research publications that describe otherwise well-designed research

 

Dr. Leung is author of the Encyclopedia of Common Natural Ingredients Used in Food, Drugs, and Cosmetics (Wiley-Interscience), which was published in 1980 and revised in 1996. He is also creator of PHYTOMED, a prototype computer database on Chinese herbal medicine developed under contract with the National Cancer Institute.


 

protocols studying such-a-such herb in ‘capsules’ or other forms with no precise product definition whatsoever.  The researchers invariably treat these herb ‘capsules’ or ‘tablets’ as if they were well-defined pure chemicals such as acetylsalicylic acid (aspirin) or codeine.  As far as I am aware, none of my well-known colleagues, except Dr. Varro E. (Tip) Tyler (Issue 34, p. 3) has found this problem to be important enough to take time to write specifically about it.1  This really puzzles me, because without a well-defined product for any study, how can one obtain any meaningful and reproducible results?  Yet many of my silent colleagues are well-known in the field.  Since these useless results constitute a sizable part of the ‘scientific literature’ of natural products, it is no wonder we continue to get such contradictory results (hence controversy) in the ‘scientific’ study of natural medicines.  Although the quality of such research has improved some over the past few years, thanks to a new crop of young scientists, herbalists, and naturopathic physicians who are more aware of the issues involved, there are still too much dubious research being conducted and too many questionable and often worthless results being published.  In addition, the existent dubious literature is still there for uninformed or unsuspecting scientists, researchers, and popular herb writers (who usually have no proper scientific training), to quote and use as legitimate data for further research, which lead to the production of more dubious data.  This situation is not going to change unless serious efforts are spent in educating the potential natural products researchers and writers to recognize the importance of product definition and to demand it as an absolute prerequisite for any study and publication in herbal medicines/supplements. 

(1) Tyler, V.E., Product definition deficiencies in clinical studies of herbal medicines,Scientific Review of Alt. Med. 4(2): 17-21(1999).

 

         To try to alert scientists, medical researchers, authors, editors, and information scientists to this problem in the phytomedicine and herbal supplement field, I published some preliminary criteria about 3 years ago in this Newsletter for evaluating botanical research.  The information contained in these criteria is still relevant today.  So I am having them reprinted below for your reference. 

 

 

Reprinted from Issue 19 (March/April 1999):

          Criteria for evaluating research on herbs and other natural products

Too many scientists and researchers investigating botanical medicines frequently treat herbal materials as if they were pure single-component drugs.  This has resulted in countless numbers of publications that are meaningless (Issue 18, pp. 1-2), which in turn has wasted considerable amount of our precious resources and mental energy in disseminating and/or debunking.  To help scientists and writers/editors who are not familiar with the intricacies and complexities of natural product research, the following are some guidelines for evaluating and accepting natural products for study or manuscripts for publication. They also will serve as basic information for abstractors to include in their abstracts of published papers.  I have divided them into 2 standard levels.  The higher-level criteria should be ones whose attainment is our ultimate goal.  With this higher standard, results of investigations in this field are more likely to be consistently duplicated.  On the other hand, the minimal-level criteria are ones that should constitute the basic requirements for accepting a natural product for research or a manuscript for publication as well as minimal information to be included in abstracts.  This lower standard is necessary for now because, at present, there are not too many publications that meet the ideal criteria.  However, as researchers not trained in the comprehensive aspects of natural products research get acclimated to this field, the ideal criteria naturally will then be adopted.

 

1.         Commercial products without disclosure of formulas.  Frequently, researchers publish reports based on a commercial or proprietary product, without revealing what the product is.  In the Chinese herbal/medical literature, there are many publications of this type.  The information in them is meaningless and useless, except to manufacturers and marketers of the investigated products.

Minimal (to allow traceability):

          Name and address of manufacturer

          Concentration(s) used in the study

          Method(s) of administration

          Source of financial support if other than manufacturer/marketer

Ideal:

          Reject the material or manuscript

2.        Pure natural compounds.  They should be treated as any pure natural chemicals (e.g., caffeine, ephedrine, huperzine A, synephrine), with indication of whether they are isolated from plants or chemically synthesized..

Minimal:

          Chemical name

          Purity

          Concentration(s) used in study

          Method(s) of administration

Ideal (      all above, plus):

          Plant source (Latin binomial), with authenticating authority

          Plant part (s), with authenticating authority

3.        Purified extracts containing artificially high concentrations of specific chemical compounds or groups of chemicals.  They include extracts of green tea with high amounts (e.g., 90%) of certain polyphenols (catechin, epigallocatechin, epigallocatechin gallate, etc.), of Asian ginseng with high total ginsenoside content (e.g., 80-90%), of grape seed or pine bark with high proanthocyanidin content (e.g., >80%), and of milk thistle with silymarin.  Since the contained chemicals are present in such artificially high levels, they no longer bear resemblance to the botanicals from which they are extracted.  These extracts are the ones that can cause the most problems.  Unless the whole extraction process (including solvents) is revealed, there is no easy way to ascertain, besides the named chemicals (markers or actives), what else is present in the extract.  For example, does the remaining part of the extract contain other even more active components from the botanical drug, or is it made up of only excipients?  What is the chemical profile of the extract?  Is this chemical profile consistent and how comparable is it to ones previously reported?  Variations among these factors can greatly affect the biological activities of these extracts.  The more precisely we identify these parameters, the more likely can the results be duplicated by future studies.  To perform scientific studies on these natural materials without addressing these issues would not yield consistent and meaningful results.

Minimal:

          Plant source(s) (Latin binomials), with authenticating authority

          Plant part(s), with authenticating authority

          Percent purity of marker(s)/active(s) in extract

          Chemical profile of marker(s)/active(s) (minimum 2 of: HPLC, TLC, GC, etc.)

          Concentrations used in study

          Method(s) of administration

Ideal (all above, plus):

          Nature of extract (solvents used and ratios)

          Total chemical profile of extract (minimum 2 of: HPLC, TLC, GC, etc.)

          Excipients used in extract

4.        Standardized extracts.  These are extracts with a standardized amount of one or more marker or active compounds.  There are 2 major types: total extracts containing specified amounts of markers or actives; and partial extracts containing specified amounts of markers and actives, but lacking other components present in total extracts.  As with purified extracts containing high concentrations of specific markers or active compounds, the same types of issues relating to solvents used and consistency of chemical profile apply. 

Minimal:

          Plant source(s) (Latin binomials), with authenticating authority

          Plant part(s), with authenticating authority

          Percent purity of marker(s)/active(s) in extract

          Total chemical profile of extract (minimum 1 of: HPLC, TLC, GC, etc.)

          Concentrations used in study

          Method(s) of administration

Ideal (all above, plus):

          Nature of extract (solvents used and ratios)

          Chemical profile of marker(s)/active(s) (minimum 2 of: HPLC, TLC, GC, etc.)

          Total chemical profile of extract (1 more of: HPLC, TLC, GC, etc.)

          Excipients used in extract

5.        Regular extracts.  These are extracts with no standardized amounts of marker or active compounds.  Their strength may be expressed in ratios between raw herbs and extracts (e.g., 4:1, meaning 1 kg of extract is derived from 4 kg of raw herb) or as percent of herb material in a specific solvent (e.g., 20% extract in 70% ethyl alcohol, meaning 100 g or mL of the hydroalcoholic extract is derived from 20 g of crude herb).  However, these strengths are meaningless unless solvents used in their extraction are given.  For example, a strength of 10:1 to describe extracts of astragalus root or Asian ginseng root is meaningless, unless the solvent(s) are clearly stated, because a normal exhaustive extraction of either herb with water will result in extracts of no more than a 3.5:1 strength.  On the other hand, an extraction with 1-butanol would yield very little extractives and thus would result in extracts of high strength (e.g., 10:1).  However, these extracts do not represent these botanicals in traditional properties or in chemical profiles.

Minimal:

          Plant source(s) (Latin binomials), with authenticating authority

          Plant part(s), with authenticating authority

          Type of extract (tincture, fluid extract, solid extract, powdered extract, etc.)

          Solvent(s) used and ratios

          Strength (ratio of crude herb to extract)

          Concentration(s) used in study

          Method(s) of administration

Ideal (all above, plus):

          Total chemical profile of extract (minimum 2 of: HPLC, TLC, GC, etc.)

          Dosage form used (tablets, capsule, syrup, drink, etc.)

6.        Crude botanicals.  Sometimes powdered herbs and fresh herbs or juices are used in studies.  It is important to be sure the following minimum information is provided.

          Plant name(s) (Latin binomials), with authenticating authority

          Plant part(s), with authenticating authority

          Form used (fresh, juice, dried, dried after processing, etc.)

          Dosage form used (capsule, tablet, drink, etc.)

          Method of administration or application (oral, topical, etc.)

          Amount(s) used in study

The above guidelines I have provided are by no means complete.  But at least they can serve as a start.  I am sure some of my esteemed colleagues who are well versed in this field will provide further suggestions and comments.  However, there are several caveats.  Thus, despite all these criteria, an uninformed investigator could always provide a plant name (Latin binomial) even though he/she may have no idea of its authenticity.  Consequently, it is imperative that the authority who authenticated the plant material be identified in the publication.  Also, fundamental problems relating to the influences of growing location, time of harvest, and age of plant at harvest, as well as other geographical and climatic factors, need to be addressed on an ongoing basis until resolution is achieved. 

I am not the only scientist who sees as a major threat to natural product research, the use of dubious plant materials, which leads to the proliferation of published information that is biased, dubious, and often plain wrong.  As the few examples described in the last issue of this newsletter [Issue 18, pp.1-2] demonstrate, we, as responsible scientists, must take the challenge and responsibility to stop this “cancer” that is growing out of control.  We need to have relevant organizations such as the American Society of Pharmacognosy (ASP) take the lead in refining these guidelines and promoting their adoption by fellow scientists.  ASP should itself encourage its own members to follow them as well as enforcing them in its own publication and publications of its sister organizations.  If we, as a small group of scientists who understand the complexities of natural product research, do not take the lead, the scientific and medical fields would be drowned in quasi-scientific herbal gibberish in 10 years.  Just look at the sudden proliferation of books, journals, magazines, and newsletters on this subject over the past 5 years!  Too much damage has already been done!

 

 

Treatment of syphilis with tufuling (Smilax glabra Roxb. rhizome)3

         Tufuling or Rhizoma Smilacis Glabrae has been used in China as a detoxicant to treat diseases like syphilis for centuries, with a recorded use history dating back to around the 5th century A.D. 

Venereal diseases were seldom encountered in China during its 5-decade closed-door communist rule.  Then, along with the increased outside contact and trading, these diseases gradually reappeared in recent years.  This is a report by a Chinese physician, Dr. Wang Qing-Quan, from the Nanping Second Municipal Hospital of Fujian Province, who treated 30 cases of syphilis with tufuling reportedly with great success. 

          The patients were all male, 22 to 56 years old.  Duration of disease ranged from 6 weeks to 4 years; 18 were primary and 12 secondary.  The treatment consisted of a daily dose of 250 g of tufuling decocted and drunk warm 30 minutes before breakfast, lunch and dinner.  Each course of treatment lasted 20 days; and efficacy was evaluated after 3 courses of treatment.  A blood test for syphilis was performed after each course of treatment and again every 3 and 6 months during the 1st and 2nd year of follow up respectively.  According to Dr. Wang, 27 of the 30 patients (90%) were cured after tufuling treatment, as evidenced by disappearance of symptoms and negative blood tests after a 2-year follow-up.  The remaining 3 patients (2 primary and 1 secondary) switched to penicillin midway during the herb treatment due to the inconvenience in decocting and taking the herbal medication (which essentially increased the efficacy rate to 100% for those who received the herbal treatment). 

The reason that this report attracted my attention is that I have been aware of tufuling and other Smilax spp. (e.g., sarsaparilla) traditionally being used in treating syphilis in China and in other countries.  I am also aware of the fact that there has not been any modern clinical evidence to support this use.  Another factor that prompted me to select this article is the herb was used here singly (uncommon in Chinese medicine) along with the employment of modern diagnostic techniques, which confirmed that it was syphilis that Dr. Wang was treating. 

This is not the first report on using tufuling to successfully treat syphilis in modern times.  Earlier reports appeared in the 1950’s and early 1960’s.  I am sure one can find more cases treated and reported in the past few years if one scans the Chinese literature.  Even though, as expected, this herbal treatment is much slower to take effect than modern antibiotic therapy, it can serve as an alternative, especially for those patients who are allergic to antibiotics or others who simply don’t want to take any modern antibiotics. 

(2) Q.Q. Wang, “Treatment of 30 cases of syphilis with tufuling,” Shizhen Guoyi Guoyao, 12((9): 822(2001);  Zhonghua Bencao Editiorial Committee, Chinese State Administration of TCM, Eds.  Zhonghua Bencao (The Chinese Herbal), Abridged Version, Vol. 2, Shanghai Scientific and Technical Press, Shanghai, 1998, pp. 2088-2092.