llle lulure is leaming tom Ille past
Much of today's research into natural medicinal products is being done by the big pharmaceutical companies. So will the Third World countries in future have to spend scarce foreign currency on re-im- porting their own plants and plant extracts? Dr Lozoya of Mexico argues that drugs of the types now under study by modern science can be manufactured by the developing countries themselves
I
t used to be generally assumed that medicinal plants could now be safely relegated to no more than a footnote in medical history. But this assumption has turned out to be a premature one. lt is true that, where once the schools of chemistry obtained raw materials from plants in order to manufacture potent new drugs, now they preferred the industrial manufacture of synthetic products, at low- er cost and in huge quantities. This also ensured a reliable supply of safe drugs in developed societies. Medicinal plants, with their old-fashioned curative proper- ties, became a thing of the past once the secrets of their chemical composition had been wrested from them and their "active ingredients" had been identified.This epoch of the great phytochemical discoveries and the establishment of basic groups of natural compounds ushered in the era of drug taxonomy and industrial patents. The powerful pharmaceutical combines laid down standards and estab- lished procedures for the use of such compounds in modern medicine. They also stimulated the development of count- less chernical versions of natural and synthetic products, rivalling Nature itself in obtaining a wide variety of derivatives from a single substance. The use of med- icinal plants in the form of poultices, infusions, baths and aromatic oils now seemed to have been superseded by
"Western" science. Only in "primitive"
cultures in the "underdeveloped" coun- tries did bonesetters, traditional birth attendants and herbalists continue to use plants in age-old ways that have done so
by Xavier Lozoya
much to enrich the anthropological litera- ture of the twentieth century.
But at the start of the 1970s this picture began to change. The first manifestations of the post-industrial age began to gain ground within the affluent society. Vari-
Shen-Nung, of whom it is claimed that he founded Chinese medicine in 2838 B.C., holds a medicinal plant in his hands. His tunic is made from the leaves of healing
plants. Photo WHO/X. Lozoya
ous social movements questioned the de- finition of health and the prevailing medi- cal system, and broached the problems surrounding ecology, nutrition and the working environment in the cities.
These trends also affected drug con- sumption. The citizens of the indus- trialised countries began to condemn the excessive, almost daily, use of phar- maceutical products. The term "iatro- genic "-applied to disorders caused by medical treatment-be.came common cur- rency, and winds of change started to blow through the health care programmes. An increased awareness of Eastern cultures also developed at this period, and lent fresh impetus to the search for alternative ways of maintaining health and coping with disease.
Acupuncture and herbalism in particu- lar attracted the curiosity of the indus- trialized society. The study of medicinal plants was revived in the West under the influence of a "back to nature" move- ment which-although not without a cer- tain snob-value and some commercial undertones-has taken root within the middle classes of the indus trial society.
All this lent encouragement to the study and development of the traditional or folk medicines of Third World countries. Peo- ple are once again acknowledging the important social fonction fulfilled in de- veloping countries by bonesetters, herbal- ists, and other practitioners of traditional medicine which, it is claimed, restores cultural and human dignity in places where more modern forms of medicine seem to have lost it. The poorer countries themselves are realising the therapeutic value of indigenous medicines, and the need to assess their curative properties.
So we have a pharmaceutical paradox.
While the developing countries are 5
struggling to industrialise, including set- ting up their own pharmaceutical indus- tries and exploiting their own raw ma- terials (to manufacture drugs that are at present imported), the developed coun- tries are going back to natural substances that have not been chemically processed, in order to obtain the "natural" drugs demanded by a post-industrial society.
Scientific studies are beginning to ex- plain some of the curative phenomena associated with the traditional use of her- bai remedies. They have, for example, established the usefulness of the local application of salicylates such as aspirin 6
Headman of a whole tribe of healers in Ecuador, this wise old man explains the properties of his herbs. Photo WHO/D. Henrioud
( the original method of using the remedy based on powdered bark of the willow tree) to treat rheumatic complaints. This method is being compared with the oral administration of the same substances.
Percutaneous absorption-through thé skin-can achieve a therapeutic effect in the affected part of the body with much smaller quantities of a given drug, without any need for the drug to enter the blood-
stream. This calls into question the classic theories concerning the distribution of drugs in the blood ! Percutaneous absorp- tion also explains the therapeutic efficacy of a hot bath containing essential oils of aromatic and medicinal plants. The pres- ence in the body of terpenes, derived from essential oils, has been demonstrated up to 24 hours after taking a bath ; the efficacy of this procedure, which combines medicinal plants with hydrotherapy, is being investigated in several chronic dis- orders.
In the light of these studies, the applica- tion of poultices, massage with plant- based liniments, and the therapeutic use of essential oils are taking on a new dimension in the medicine of the future.
A similar development is taking place in the study of the pharmacological effects produced by plant-based infusions. lt used to be argued that pure chemico-phar- maceutical compounds must be superior to the complex mixtures of substances generally found in an infusion, because it was bard to standardise the latter and to administer them in accurate doses. But the advent of an effective technology of chemical analysis, using high-resolution chromatography, mass spectrometry and nuclear magnetic resonance, makes it easier to identify and quantify the chemi- cal ingredients of a mixture.
Is there then a place in scientific medicine for plant-based infusions? Most certainly there is. Nowadays such prepa- rations are described as "mild" remedies for treating minor aliments and general disorders of the body. Studies on the way in which camomile tea, for example, alters the hormonal balance or helps to reduce inflammatory processes appear to revolutionise some of the dogmas of
"orthodox" pharmacology. The treat- ment of diabetes mellitus with plant ex- tracts is becoming part of "Western"
medical practice, and investigations are under way into the combined action of the vegetable substances which make up the traditional potions used for this purpose.
In reproductive biology too, potions made from herbs have made an appear- ance. The development of new plant- based products which have the property of causing abortion- a fact known to the indigenous civilisations of Central Ameri- ca for more than 500 years-suggests the potential use of an infusion as a method of birth control.
Thus simple plants in their traditional forms of use-laxative decoctions of roots, antipyretic teas of leaves or flowers, oily poultices of analgesic or stimulating herbs, crude extracts to regulate menstruation, glycaemia-reducing plants taken orally in
combination with food, fomentations or massages using natural anti-influenzal substances, and sedatives of vegetable origin-are gaining acceptance from late twentieth-century science. There is high promise that in the future, in combination with other familiar natural rèsources such as antibiotics and hormones, they will become part of a new assortment of drugs suited to current health needs.
lt is ironie that medical circles in many developing countries, where a centuries- old knowledge of herbal remedies is part of popular lore, persist in believing that research on medicinal plants is out of date,
Dr Xavier Lozoya (right) discusses a medi- cinal plant which has already been system- atically analysed at the Biomedical Re- search Unit on Traditional and Herbai Medicine in Mexico City, of which he is the Director ! Photo WHO/J. Bland
and that their use is merely part of the folklore of under-privileged indigenous groups in those countries. They also main- tain that, once industrialisation and high technology bulldoze their way into the most remote rural areas and provide them with the benefits of the "modern world,"
herbal medicine will become a thing of the past.
Such thinking in the Third World coun- tries is out of step with that in the indus- trial and technological regions, where scientific research into traditional thera- pies is nowadays considered to be of undoubted importance for the future.
The new era of natural medicinal pro- ducts, of "biodrugs", has begun, and it is the pharmaceutical combines which are developing much of the relevant research technology. For those of us investigating this field in the developing countries, the question arises: will we in the future have to spend scarce foreign currency to re-
import our own plants and extracts? Are we going to lose the battle once again?
In the middle of the present century, when the great pharmaceutical industry was growing up, we lacked the technology and scientific knowledge to manufacture drugs. Our role was limited-at best-to providing raw plant materials. Today it is in the countries of the Third World that the tradition of using medicinal plants survives in its least adulterated form, and this makes it easier for us to identify the plants which need to be scientifically evaluated. Drugs of the types that are now being studied by modern science could be manufactured with the level of technology already attained in many developing countries. All the evidence shows that the gulf between traditional medicine and scientific medicine is at last beginning to close and need no longer be regarded as an obstacle in the path of scientific
progress. •
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