Number 32
May/June 2001

Herbs in this issue:

Honeysuckle flower




A Note From Dr. Leung


Pharmacognosy revisited


     The word pharmacognosy has variously been defined by different authorities as ‘the knowledge of drugs,’ ‘the knowledge of drugs from natural sources,’ and ‘the science of crude drugs,’ among others.  The Merriam Webster’s Collegiate Dictionary, 10th Edition, defines it as ‘descriptive pharmacology dealing with crude drugs and simples.’  I don’t know where this dictionary obtained its information regarding pharmacognosy, but I have never known it to be a part of pharmacology.  According to Dr. Heber W. Youngken, who wrote the classic “A Textbook of Pharmacognosy” which we used in Pharmacy school in the fifties and sixties, pharmacognosy is “the science which treats of the history, production, commerce, collection, selection, identification, valuation, preservation, and use of drugs and other economic materials of plant and animal origin.”  Nevertheless, the fact is that no one single definition describes the field we call pharmacognosy as it has been practiced over the past   


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.


several decades.  It is definitely multidisciplinary, encompassing botany, chemistry, and pharmacy (including, yes, pharmacology, because some pharmacognosists specialize in pharmacology, but not the other way around.).  Nevertheless, a precise definition that reflects the pharmacognosy as a discipline now being taught in American institutions would be difficult. 

        The precursor to pharmacognosy in the West was a field called ‘materia medica’ which simply means medical materials.  Before synthetic drugs appeared, ‘materia medica’ was the only game in town.  Textbooks of materia medica dealt with both crude drugs (pharmacognosy) and pharmacology.  Later, pharmacognosy and pharmacology became independent fields, and pharmacognosy finally evolved into something quite different from its original form.  Athough I am not that old to have studied ‘materia medica,’ I am old enough to have studied classic or traditional pharmacognosy – a field that involves the identification of crude natural drug materials (plant, animal, and mineral) by organoleptic, microscopic, and physicochemical means, the study of their origins, properties, and economic aspects, and the extraction of their active components, etc., in addition to such more specialized topics as biosynthesis, biochemistry, and pharmacology.  During the past 25 to 30 years, the pharmacognosy taught in American pharmacy schools has evolved basically into the field of phytochemistry (plant chemistry).  Most graduates with advanced degrees in pharmacognosy now can no longer recognize natural drug materials because they have never been taught to do so.  Instead, they only know how to analyze and/or isolate chemical compounds.  That qualifies them basically as natural product chemists or phytochemists who can equally be well trained in departments or schools of chemistry, rather than pharmacy.  Because of this, the field that bears closer resemblance to classic/traditional pharmacognosy than the ‘pharmacognosy’ being taught in American universities today is ethnobotany.  But ethnobotany lacks weight in chemistry and pharmacology as modern pharmacognosy lacks weight in botany and crude drug identification.  Depending on the schools where pharmacognosy is taught, you can find graduates with widely different capabilities.  But the fact is that few, if any, recent graduates of pharmacognosy from American institutions can be considered true pharmacognosists with multidisciplinary expertise in crude drugs (e.g., identification per macroscopic and microscopic examinations) as well as phytochemistry and pharmacy.  With the current back-to-nature trend and an increasing number of consumers taking natural supplements and herbal medicines, the demand for pharmacognosists should increase sharply.  However, due to the diversified nature of ethnic herbal medicines, especially the Chinese and Ayurvedic medical systems, even traditional pharmacognosy (largely a Western scientific field) is not adequate in dealing with problems arising from the fundamental differences between modern conventional allopathic medicine and Eastern holistic medicine.  While a well-trained traditional pharmacognosist possesses the expertise necessary for discovering and producing conventional drugs from natural raw materials, he/she sorely lacks training and expertise in dealing with herbal medicines as they have been and are traditionally used. 

         In short, although traditional pharmacognosy is more appropriate than other fields in dealing with dietary supplements and herbal medicines, it is by no means adequate, especially by itself.  On the other hand, phytochemistry and the ‘pharmacognosy’ currently being taught in most American pharmacy schools, being no different than chemistry of natural products, are totally inadequate, except for dealing with the chemical aspect of these dietary and medicinal substances in a limited fashion.  Yet, the ‘dietary supplement’ field is dominated by chemists and botanists, few of whom have the expertise and insight beyond their immediate areas of training.  And there is little understanding, on the part of these experts, of the non-chemical and non-botanical aspects of herbal medicines/supplements.  Because of these, a major void (which is frequently ignored or slighted) exists in the methodology of conducting scientific investigations and clinical trials on ‘dietary supplements’ that include herbal medicines. 

         Is traditional pharmacognosy, with its multidisciplinary embodiment, adequate in handling the various technical aspects of dietary supplements and herbal medicines?  The answer is no.  It can only deal adequately with the discovery of new single-component drugs from plant sources, and its embodied disciplines do not include one that deals with the traditional aspects of herbal medicines as they have been practiced for centuries.  Consequently, anything other than well-defined chemical compounds is problematic for most scientists who engage in herbal medicine/supplement research.  I must confess that for years I had the same mentality, which is thinking in terms of well-defined chemical drugs – a plant is a (chemical) drug, a plant species is a (chemical) drug, an extract is a (chemical) drug, and so forth, without giving it a contrary thought, because we have been trained that way.  The closest thing to a breakthrough in the natural products field in recent years was the requirement for using Latin binomials to precisely identify or define a plant species being investigated or used as medicine.  But then, complacency took over; and researchers started equating an herbal drug with a plant species or a ‘medicinal plant.’  Even though we are well aware of the fact that a plant is not necessarily equivalent to a drug, we seldom seem to make any serious efforts to differentiate the two.  And I must confess that I have been a guilty party to this complacency that has resulted in a copious amount of scientific literature which is ambiguous and confusing.  Like my colleagues, I used to simply stop at the Latin binomial when identifying an herbal drug, without looking further into what the ramifications were.  Such as what part of the plant, how is it prepared or extracted, and how is it administered, etc.?  But I have outgrown that, albeit only in the last few years.  Unfortunately, most of my influential fellow scientists haven’t.  Thus, research papers on herbs are still being published in reputable, peer reviewed journals identifying an herbal drug simply by the name (Latin binomial) of the plant species from which it is derived.  It has gotten to the point I don’t even consider any findings reported in any publication (no matter how reputable) as credible unless I have actually read the original paper and found it so.  As I have alluded to this fact before, the adverse effect of the recent natural products revival is a massive spate of publications few of which are accurate or considered trustworthy, irrespective of how well known their authors or how well these books and magazines are promoted.   A typical example of a very well-promoted but extremely egregious book is The Complete Guide to Herbal Medicines which I have reviewed and provided comments on less than 5% (!) of its contents in previous issues of this Newsletter [Issues 27-29] and reprinted in HerbalGram [52: 71-72(2001)] and which is also critically reviewed by a colleague and friend, Dr. Dennis Awang.1  There are many others, though less egregious.  As I have said in earlier issues of this Newsletter, if this spring of misinformation were not plugged in time, we would be drowned in a sewage of misinformation!  To correct this problem we must start with education!  Although most major medical and pharmacy schools now have courses in herbal medicine, it is very important that they be taught by qualified herbalists, pharmacognosists, phytochemists, botanists, ethnobotanists, economic botanists, ethnopharmacologists, and/or pharmacists, etc., who have a clear concept of exactly what the herbal medicines are which are being taught.   The current pharmacognosy curriculum is no longer adequate, even if it happens to re-include its classical aspects.  It must include aspects of traditional herbal medicine in order to meet the growing needs of modernizing herbal medicines.  It should no longer be simply a field that teaches the identification and use of crude natural materials for new drug discovery.  

    Alternative and/or complementary medicine, which includes traditional herbal medicine, can be a distinct and independent health-care system (e.g., TCM and Ayurvedic), separate from our modern allopathic medical system.  It is as useful and valuable as conventional medicine and should not be treated merely as a source of raw material for isolating and discovering conventional drugs.  As more and more we discover the validity and usefulness of these herbal medicines the way they have been traditionally employed, it’s essential that we continue to retain and acquire the necessary knowledge for further discovery and validation of these useful health-care tools.  The way to start is to broaden the field and teachings of pharmacognosy to reach beyond conventional drug discovery to include different aspects of traditional herbal medicine.  

(1) D.V.C. Awang, Phytomedicine (in press).


Latin pharmacopoeial/pharmaceutical names for herb drugs?

        After observing the complacency and sloppiness in publications that frequently make no distinction among plant species, plant parts, plant extracts, and drugs, I think it’s time to revive the use of Latin pharmacopoeial/pharmaceutical names.  I don’t know why we dropped their use here in America in the first place.  With the Latin pharmacopoeial names, at least one of the major confusing aspects of studying and reporting in herbal medicines and dietary supplements  (which leads to misinformation and wrong information) will be removed.  Thus, for example, instead of simply using the Latin binomial Crataegus monogyna to describe hawthorn berry, leaf, flower, and leaf with flower, the use of Crataegi fructus, Crataegi flos, Crataegi folium, and Crataegi folium cum flore will automatically define the plant parts used, avoiding the pitfall of using the Latin binomial alone.  Although I said earlier the use of Latin binomials could be considered a breakthrough in pharmacognosy and related fields, it seems to be also one of the major causes of the current problems in the natural products literature due to complacency and a false sense of having achieved precise identification by simply using Latin binomials.


Honeysuckle for treating acute periodontitis [Neimongol Zhongyiyao (2): 37(2001)]

         This is a report from the Municipal TCM Hospital of Qingyuan in Guangdong Province.  The authors (Yuan Ping and Yao Shu-Guang) claim that they have used this treatment repeatedly with consistently satisfactory results, though they do not give the number of patients treated, except for a case example. 

The treatment is quite simple:  A small amount of dried honeysuckle flower buds (1-2 tablespoons) is washed briefly in boiling water.  It is then chewed to a mash and placed at the root of the afflicted tooth.  Repeat this every 2 hours or so, especially once before retiring at night.  Be sure to swallow the juice and herb.  The authors report that all symptoms would disappear in 2-3 days. 

Using this treatment, the pain around the affected tooth is greatly reduced after 1-2 hours.  After 2-4 hours, the gum swelling gradually subsides until after 24 hours it normally disappears completely along with the pain.  If lymphadenitis has developed in the jaws, then it will take 3-4 days to subside with this treatment.  Hence the authors advise that this treatment be started as soon as periodontitis occurs to avoid the lymph nodes being affected. 

The following is a case example given by the authors.  A 42-year-old male laborer suffered from repeated acute periodontitis (5-6 times/year) for more than 8 years.  Each time it was treated with antibiotics which controlled the pain in 2-3 days.  When the patient was treated with the honeysuckle method, the pain was greatly alleviated after the first 2 hours; and with continued treatment for 3 days, all symptoms were resolved.  Thereafter, the recurrences were treated in the same manner, with pain being greatly reduced within a few hours of treatment.  Compared with the use of antibiotics, this treatment greatly reduced the patient’s suffering and economic burden. 

It’s obvious that this patient had poor preventive dental care.  However, since his periodontitis did occur and recur, the honeysuckle treatment is quite logical if you know the traditional and pharmacological properties of honeysuckle flower.   This herb has been used for at least 2,000 years (first recorded in the Shennong Herbal around 200 BC-100 AD) to dissipate heat (fever), reduce inflammation, and to remove toxins (including pathogens), especially in such conditions as bacterial and viral infections (bacterial dysentery, enteritis, skin sores and boils, cold and flu, etc.).  Unlike the fresh flower, it has none of the characteristic fragrance.  Its taste is slightly bitter to some and not objectionable to others.  Major chemical constituents present in honeysuckle flower bud include chlorogenic acid and isochlorogenic acid, saponins, flavonoids (luteolin, luteolin-7-glucoside, etc.), a volatile oil (mainly linalool, aromadendrene and geraniol), tannin, and inositol (~1%).  The chlorogenic and isochlorogenic acids, saponins, and luteolin are responsible for some of the herb’s pharmacological effects. 

Leung, A.Y., and S. Foster, Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics, Wiley-Interscience, New York, 1995, pp. 536-537; Leung, A.Y., Chinese Healing Foods and Herbs, AYSL Corp., Glen Rock, N.J., 1984, pp. 87-90; Leung, A.Y., Better Health with (Mostly) Chinese Herbs & Food, AYSL Corp., Glen Rock, N. J., 1995, pp. 47-48.


Are some of us still ugly Americans?

         Americans are the most open and generous people, but due to the young age of our nation, we are also, relatively speaking, the most uncultured, impatient, and often misunderstood.  Like a teenager in his prime, we tend to consider ourselves the ones who hold the truth and often are so self-absorbed and self-centered that whatever we do we believe to be the best for others as well.  Because of our insensitivity, we occasionally hurt others without meaning to.  Hence, sometimes we are ugly Americans.  Two recent events have reminded me of our ugly trait.

         A recent article in the Wall Street Journal (September 13, 2000, B1) titled “Geneticists Focus on a Controversial Treasure:  All the DNA in China” is rather revealing.  Researchers from several well-known institutions including Harvard, Vanderbilt, our own government’s National Cancer Institute, and USC, as well as a genetic drug company, are collecting DNA samples from hundreds of thousands of Chinese individuals, purported to study the genetic basis of obesity, asthma, cancer, and other major diseases and then find ways to prevent them.  The authors write, “China’s very backwardness is an asset for researchers.  Many rural families have lived in isolation for generations, making it easier for genetic sleuths to trace illnesses through relatives.  The lack of treatment for conditions commonly treated in the U.S. – hypertension, say, or asthma – presents scientists with a “pure” gene pool.  And growing wealth and mobility within China are putting pressure on scientists to mine its data before those ideal conditions disappear.”  Also, “But the cross of cutting-edge research with isolated and sometimes illiterate populations creates a situation ripe for abuse.”…. “The potential for exploitation is beginning to draw protest in China and abroad.  Chinese researchers have accused foreign companies of “stealing” China’s genetic resources for huge potential profit and applying double standards to how they operate in developing countries.”  This certainly reminds us of American drug companies’ largely unsuccessful ventures into “jungle medicine.”  Now that Third-World countries have learned the Americans’ true intentions, they no longer make it easy for us to explore their jungles.  Since times have changed and we are at the outset of a new era for new drug development through genetic manipulation, the Chinese population is now the “jungle.”  And the Americans are coming, quietly, to take advantage of the richness of the “forests” before these disappear.  What will happen to the new discoveries?  And this time around, chances are there will be some success if these studies are allowed to continue.  No doubt they will be turned into some forms of commercial items (devices, drugs, or whatever) and sold back to the Chinese at exorbitant prices – a double whammy!  I am sure most of the Americans involved are sincere people who mean well.  However, it only takes 1 or 2 insensitive ones to claim the title of ugly Americans.

         The other incident is more personal.  This involves The National Geographic (NG), which is as American as apple pie, and one would never expect it to have an ugly side.  About 2 years ago, it was producing a coffee-table type of book on herbal medicine.  At the eleventh hour, its editors realized that the author had not included Chinese herbal medicine, one of the most important topics, without which any book on natural medicines will be seriously lacking in credibility and scope.  I was contacted, thanks and no thanks, Jim (aka Dr. James Duke, a colleague and friend).  Since it just happened that I was going to China with a couple of colleagues to visit some ginseng farms in a month anyway, we agreed to take its photographer with us, and pulled a few strings to get her access to different institutes and companies, as well as provided her with knowledgeable professionals who speak English.  When the book was published, with numerous pictures from that trip forming a prominent part of the book (some of which had captions using my translations), there was not a single thank-you or acknowledgement of the efforts of my Chinese colleagues/associates and me on its behalf, even though there are 2 full pages of acknowledgement.  A letter I sent to responsible executives at NG, expressing my disappointment and amazement at the author’s lack of professionalism has been ignored – over 6 months now.  Can it be deep down, without its conscious awareness, NG is an ugly American? Incidentally, my Chinese colleagues and I did all that work for NG with the verbal promise from its photographer that we would get some publicity for our respective institutes and small companies, which was after all, liberally given to other American companies (including that of a Caucasian colleague and friend’s) in the book.  Even paid consultants like another one of my colleagues/friends, got acknowledged.  Is it because perhaps he is Caucasian?  I have the greatest respect for NG and its work and can’t imagine a world without its publications and television adventure programs.  I have no way of knowing whether NG has been an ugly American all along and I am inclined to believe otherwise.  I would be interested in hearing from my non-Caucasian readers whether they or their associates have had similar experience with NG.