Research into medicinal plants: The Somali experience

ABDULAHI S. ELMI

Department of Pharmacology
Somali National University
Mogadishu (Somalia)

Introduction

Herbal drugs have a considerable use throughout the World. In the past centuries, such use was understandably more extensive when related to the density of the populations. Treatment with herbal drugs seemed to be destined to vanish with the development of biomedicine. Instead, what actually happened is that despite the expeditious and impressive progress of "modern medicine" in the course of this century, ethnomedicine has remained the chief therapeutic reliance for hundreds of millions of people.

People have recourse to herbal drugs for a variety of reasons. A large number of persons depend on medicinal plants, mainly because they have no access to modern medicine. These people mostly live in rural areas, or in peripheral slums of big cities. For some people, especially in economically developed countries, plant-derived drugs are associated with memories of good old days. Nostalgia for grandmother's remedies are an inducement for many to try such remedies. Certain people believe that natural products have great efficacy while being devoid of toxic effects. Some people rely on modern medicine for certain diseases, while for others they resort to traditional medicine.

The use of herbal drugs by many is the result of balanced judgement based upon personal experiences, or acquired through reliable scientific sources. Whatever the reasons behind the utilization of herbal drugs, the merits of this system of treatment is unquestionable. It is unfortunate that some people associate it with the nostalgia of the past or link it with poverty. Herbal drugs are neither the medicines of the poor alone nor the remedies for nostalgic people; they are not merely a great potential for delivering health care for all in the future; they are actually an important tool for treatment of millions of people of different culture, social class and status throughout the world.

In today's world therapeutic year of armamentarium, plant products are well represented. Farnsworth points out that one quarter of the total prescription drugs in industrialized countries contain one or more components derived from plants.

Furthermore, scientific research has very often shown that in spite of being based on empirical systems, traditional herbal remedies are the result of long standing positive experience.

It is time that the experience of so many generations be placed at the service of modern man without loosing time or necessarily making use of expensive and sophisticated methods. The goal of improving and exploiting the use of medicinal plants in health care can be achieved with relatively easy means and in reasonable time.

Herbal drugs in Somalia

Traditional medicine uses different methods for curing diseases. The Somali traditional medicine could be divided into: (a) ceremonial healing and (b) practical treatments and herbalism.

Ceremonial healing:

This system is based on the celebration of specific rites. Some of these are purely religious. Others are located in the sphere of the magical and others are a mixture of both. The magic rites deal often with spirits and the treatments are mainly for mental or psychosomatic disorders. Famous among these rites are: the saar, hayaat, mingis, nuumbi, etc.. The religious treatments are based on the islamic teaching, that is the Koran, and give health to the true Muslim believers. Religious healing is for both organic and psychic diseases.

Practical treatments and herbalism:

These systems deal more properly with organic disorders. Most common among these are: (i) cauterization, (ii) scarification and blood letting, (iii) bone-setting, (iv) surgery, and (v) use of herbs. Traditional medical treatments are well approved and widely used by the Somali population. Surveys on traditional medical practices carried out by the Division of Pharmacology of the Faculty of Medicine in different times, showed very high prevalence of this type of medicine within both the rural and the urban communities. Among other information, one survey indicated that in the male population, the administration of herbs reached 73%. Several hundred plants are used in Somali traditional medicine. The confidence of the population to the ability of traditional herbalists is great. The use of plants is not devoid of spiritual rites. In the Somali traditional medicine, there is a great respect for the plant. Eradication of the whole plant is avoided, even if the used part is the root. This shows also a respect to the environment. Healers of the inter-riverine area do not consider the plant as a simple physical entity. Greater part of herbalists feel that the effect of a plant depends not only on its power, but also on the relationship between the collector and the plant itself. Usually, a healer avoids his shadow on the plant while collecting it. He says prayers or recites formulas before cutting the plant. The recited words or formulas may be words from the Koran or prayers to ancestors. It is important that the rules laid down by the ancestors be strictly followed.

Most herbalists make use of no more than 30-40 different plants. Nevertheless, the average number of plants known to the majority of healers is far greater than that. Many herbalists could easily list over 100 plants, indicating the purpose they are used for in traditional medicine. In this they are like the modern physicians, who in spite of the great armamentarium of drugs at their disposal, feel more convenient to prescribe few dozens of drugs during their lifetime. The average inventory of kinds of leaves, stem barks and roots in Mogadishu traditional herbalists' dispensaries do not exceed the number of 35-40 for each. While in the rural areas healers very often go out into the bush in order to collect their own herbs such is not the case in the cities. The herbalists who are also dispensary owners would employ an apprentice, or younger herbalist for this job. They also buy herbs by occasional suppliers. By doing so, much of the magical aureola is neglected. They prefer to pretend that their suppliers have complied to all traditional plant collecting regulations. Many herbalists of the cities probably do not give great importance to the "rules of the ancestors".

Herbalists of big centres may act as healers or simply as dispensers. In fact they may dispense herbs on simple request by the patient or according to another healer's prescription. This is quite a difference compared to their rural counterparts, who gather herbs upon clients needs. Traditional herbalists are allowed to practice their profession without restrictions. On the other hand, the law is not clear on whether clinical trials with plants could be performed.

Research experience

A programme of research into medicinal plants was established by the Somali National University in 1978. Investigation on plants used in traditional medicine is also one of the main lines of research of the Somali Academy of Sciences and Arts. The aims of the research that started in 1978 are:

(a) to foster the accomplishment of better use of medicinal plants lending to the necessary scientific support;

(b) to examine the credits of traditional use of medicinal plants in the light of modern science so as to encourage the use of therapeutically effective plants and discourage harmful ones;

(c) to promote the integration of proven valuable knowledge in herbal and modern medicine;

(d) to stimulate and cooperate in the realization of Somali traditional pharmacopoeia;

(e) to reduce the country's drug bill;

(f) to help in creating a national pharmaceutical industry;

(g) to aid in the therapeutic, economic and commercial exploitation of medicinal plants, by promoting their use, culture and exportation.

The research is a multi-disciplinary enterprise requiring the contributions of botanists, chemists, pharmacologists, and clinicians. At the Somali national University, the research on medicinal plants involves the Division of Pharmacology, Faculty of Medicine, the Section of Organic Chemistry, Department of Chemistry, and the Division of Botany at the Faculty of Agriculture.

At the very beginning, in 1978, we designed our programme just following the classical approach for drug research. Great importance was given to the isolation and structure elucidation of active compounds and pharmacological screening on them. After sometime, the team of research realized that the system chosen for the research was not the most appropriate to attain the aims of the programme at reasonable time. Further discussions brought about some changes and a decision was made that the research phases be as follows:

(a) Inventory of botanical identification of plants used in traditional medicine.
(b) Literature survey of the identified plants.
(c) Verification of efficacy of selected plants.
(d) Safety and toxicity assessment of active plants.
(e) Isolation, identification or structure alienation of active principles.
(f) In-depth pharmacological and toxicological evaluation of isolated active substances; and
(g) Production of drugs based on plants containing therapeutically valuable substances.

Extensive work has been accomplished on each of the above phases. The plants to be investigated upon are not chosen at random, but according to clearly set priorities. These priorities are linked to:

(i) the prevalence of the use of the plant among the population;
(ii) the prevalence of the disease for which the plant is used. Additionally, plants used for diseases which have no good cures in modern medicine, are given due consideration.

Regarding the inventory and botanical identification, information on the use of hundreds of plants has been collected by interviewing traditional herbalists. Many plant collecting expeditions have been carried out. All the collected plants have been identified. Samples of collected plants have been sent to internationally important herbaria.

Literature information has been collected for a relevant number of plants. This was partially carried out in Somalia. Lists of names (with synonyms) of identified plants were sent to the WHO collaborating Centre for Traditional Medicine at the University of Illinois, Chicago, USA, for search, through the NAPRALERT computer file. Literature printouts for most of the identified plant species have been obtained from the above Centre. The Medicinal Plants News-letter published by OAUSTRC, also reports literature information on medicinal plants.

Following the above system, extensive experimental research through the use of in vivo and in vitro pharmacological methods has been carried out. The performed activities include: isolated organ tests, antimicrobial and antiparasitic activity, anti-inflammatory activity, anti-ulcer activity and several others. Toxicological studies have been performed on a number of plants.

The isolation and identification of active principles has led to the elucidation of the structure of a number of compounds. Some of these compounds, such as, two 1,3-diarylpropan-2-ol derivatives, called quracol A and quracol B, are new compounds hitherto not found in plants. One of the positive results of this chemical research was the identification of a cocancerigenic compound (a phorbol diester) in a plant species, the oil of which was commercially exploited by a Government agency for use as a purgative.

The last step is the clinical evaluation of efficacy and safety. This is the most difficult phase, especially because of the ethical implications and the long time required for carrying out appropriately controlled clinical trials. We elaborated a strategy that would allow us to monitor some clinical effects before starting with controlled clinical trials. Since the traditional medical practitioners are allowed to practice their profession, we decided to assign a physician to a qualified and licenced healer. The healer's job was mainly observation of the healer while he practises. This arrangement was not difficult, because a practicing healer was in fact among the staff of the Division of Pharmacology. The observations yielded valuable information on several plants.

The research programme has given a lot of interesting and useful results. The new approach has shown to be better suited for the aims of the programme. Nonetheless, it has many shortcomings.

The experience has shown that it still neglects the most important and immediate objective of medicinal plants research in a developing country: the early utilization of these plants in Primary Health Care. Most of the research programmes in developing countries share these drawbacks.

More appropriate method for applicable research

The research into herbal drugs usually makes use of dried plants, while we know that such plants are normally administered by traditional medical practitioners in the fresh state. Moreover, the solvent used by the practitioners is water.

The classical method for research is to dry the plant, store it for some time and then subject it to extractions with different types of solvents. Thus the approach of the researcher is quite different from that of the operators of the type of medicine which is under evaluation. It is clear that the researcher directs the work in a way more compatible with the setup of the research facilities and methodologies. The latter are established according to drug research of pure chemical compounds. In fact the rest of the research sequence is testing on laboratory animals and later on clinical trials as is classically done with synthetic drugs.

Is this method appropriate for plant material? Many plants undeniably lose totally or partially their activity during the drying and storing process. Therefore biological as well as chemical studies must be performed on fresh plants. The use of solvents and fractionation may result in greater concentrations of active compounds and stronger activity. But this is not always the case. In fact, sometimes total activity decreases with fractionation.

The classical method gives undue importance to the isolation of pure active compounds from medicinal plants. While isolation and identification of single active compounds is interesting for studies of structure-activity relationships and may be stimulating for the scientist, it will not contribute to any significant extent to the solution of health problems of developing countries. It is imperative that research methodologies be made more respondent to the principles of traditional medicine and to improved objectives. We must consider that traditional medicine has, in many countries, greater prevalence and accessibility than modern medicine. There is no doubt that the trend will remain the same for many years to come.

For the hundreds of millions of people who live in rural areas, changes of attitude and the established use and acceptance of modern health care facilities will be very gradual. Therefore, the immediate useful arid most important contribution of scientists in this field is how to make the traditional curing systems safer and confirm or disprove the efficacy of the preparations which so many people make use of.

If research into medicinal plants is oriented to reach this very important goal, it can be carried out in an easier, quicker and cheaper way, than the methods which are normally applied in most research centres of developing countries. People in our countries are using herbal remedies although for most of them the toxicity has not been studied. It is the duty of scientists to investigate the toxicity of every product which is consumed by humans. One of the first investigations on all medicinal plants, regardless of their efficacy is, therefore, the study of their toxicity.

The second step is the evaluation of the activity for which the plant, or combination of plants, is used. If for nothing else, it is very unwise and wasteful to use something when it does not serve the purpose for which it is used.

Once enough information has been acquired on the safety and efficacy of a certain traditional remedy, this knowledge must be transferred to those who prescribe the treatments and, possibly, to the clients who make use of such treatments. Normally, the results on the investigations of plants remain in the drawers of the laboratories or in libraries as printed materials and they will never reach the user of the plants.

The method that we deem best respondent to the needs of our communities is as follows:

(a) toxicological study in two species of animals for acute and subacute toxicity;

(b) experimental evaluation of the activity for which the supposed remedy is used; and

(c) clinical evaluation for efficacy in humans (where possible this must be preceded by observation of the healer while using the remedy).

The fact that the plant is already used by healers on humans should not, by any means, save it from the necessary ethical obligations during clinical trials.

The advantage of this model is that the costly, sophisticated and time-consuming chemical studies of separation, subsequent fractionations and structure elucidation is avoided. These steps, in fact, are not necessary for the needed progress towards a better use of medicinal plants in health care. This approach takes into account the concepts of traditional and folklore medicine. We cannot expect that traditional medical practitioners make use of pure extracts, or fractions of the plants they use,

The organization of training courses and workshops with the participation of healers would contribute to the improvement of their knowledge and skills and to the consolidation of a safer and more effective community health care system. Healers trained and left to operate in their communities would be the best fabric for Primary Health Care.

The achievement of this goal would be the greatest satisfaction and victory for scientists engaged in research into medicinal plants.