Drugs From The West IndiesAuthor(s): Compton SeaforthSource: Caribbean Quarterly, Vol. 7, No. 4 (April, 1962), pp. 198-202Published by: University of the West Indies and Caribbean QuarterlyStable URL: http://www.jstor.org/stable/40652784 .

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Drugs From The West Indies COMPTON SeAFORTH

Chemistry Department, U. C.W.I., Jamaica Nowadays it is often argued that the threat of a third World War diminishes with the upgrading of living standards in more and more of the poorer countries to the level of those in the better equipped countries. This is a sort of social pressure which works alongside the forces of nationalism to improve living standards, through the conquest of ignorance and disease in the lesser developed territories with the minimum of dependence upon others. To deal with the aspect of the conquest of disease, every nation must carry out its obligations to safeguard the common heritage of world health, if it is to keep the trust of others. It must be able to protect its own health, and in con- sequence the health of its neighbours. Moreover, if it would stand on a foot- ing of equality with other nations it should contribute towards the discovery of cures for the ill-health in the world. To make this contribution, non- industrialised nations such as those in the West Indies should direct most of their actions towards suitably developing their natural resources.

Scientific research is a necessary part of every country's plan for the development of its natural resources. It is a long term economy which may best be utilised through a permanent agency set up for the specific purpose of obtaining and co-ordinating the results of such research. This essay attempts to show why a Caribbean government organisation should be established to encourage the exploitation and development of the flora of the West Indies, for possible sources of new drugs, through application of the results of both local and overseas phytochemical research. Such a research organisation could he run efficiently on less than 0.2 per cent, of the gross national product of an}- of the progressive economic units making up the West Indies : 0.2 per cent, of the national income was the figure recommended for basic scientific research to all countries by a N.A.T.O. study group consisting of eminent scholars, who met in 1960 in the Foundation Universitaire of Brussels. There is another factor which should encourage a West Indian government to finance this sort of research project. The weight of public opinion would almost certainly favour a government body searching for drugs in the many West Indian plants reported by folk-lore to contain medicinal principles. People should support such action because of the promise it would bring of crystallising their own myths. And the chances are that this promise may well be fulfilled! For there are examples of the discovery of powerful new pharmacologically active substances in West Indian plant species. The Jamaican periwinkle {Vinca rosea L.) makes a "bush-tea" which is described locally as a cure for colds and fevers. From this periwinkle, chemists have lately extracted a new drug called vincaleucoblastine which can cure some forms of cancer. Wild susumber (Solanum verb asci folium L.) as well as other members of the botanical family, Solanaceae, are used among country folk for their insecticidal and other biological properties. From wild susumber, a chemical known as solasodine is obtainable which may be converted by microbiological methods into hormones, growth substances of importance to health and well-being in humans. There are other cases of how chemical study of the lush West Indian vegetation has yielded valuable results over a period

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of less than ten years. Any West Indian reader can add to the periwinkle and the susumber a long list of local plants which reputedly lower blood pressure, cure the social diseases, and so on. Of course, collaboration in this research may be desirable between the government and interested individual institutions at home and abroad. But any new sources of drugs would be of greatest economic benefit to the countries to which the plants are indigenous.

Health is a necessity for the full enjoyment of life. In order to maintain it and to improve it, today, we rely on hormones, on substances which alleviate pain and cure the diseases which afflict mankind, on insecticides by which the destroyers of food and clothing and the carriers of disease are destroyed, and on anaesthetics which enable the surgeon to perform operations which would otherwise be impossible. These substances are often synthetic, they are built up in the laboratory by chemical means from simpler, more readily available materials. However, the formulations of many of these drugs are planned according to the formulations of those chemicals of similar physiological action which were previously extracted from plants. The rest of this essay will show in special cases how new drug formulations arise from the results of the chemical studies of plant products.

This type of development work is undertaken by the practitioner of chemistry rather than the pharmacist. The pharmacist or dispensing chemist is concerned with the accurate dispensing of medicines prescribed by the doctor, and these medicines are compounded of known drugs. But, the research chemist in this field of study sets himself the more difficult task of finding entirely new remedies, often from among new types of substance in which there would be no reason to suspect therapeutic action. This chemist sets out to learn the detailed formula which is the chemical structure of his new compound, in terms of the types, numbers and arrangements per group of chemical atoms that make up the compound.

We know that chemistry teaches that every material thing is ultimately composed of a pattern of atoms (i.e. chemically indivisible units), which is called a molecule. Chemistry teaches that the geometry of the molecule of any compound and the manner in which its constituent atoms are bonded together determine all the sensible qualities of the particular compound. The molecules of ammonia (I), of ethyl alcohol (II) and of carbolic acid (III) are represented by the following chemical formulas.

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H, C, N and O represent the relative positions of the atoms of hydrogen, èárbon, nitrogen and oxygen respectively, bonded in the manner represented by the straight lines. Carbon atoms are sometimes represented by the inter- section points of the bond-lines in the formula, (see (III)). The greater the variety of known patterns which perform, say, a specific biological function the better equipped the chemist becomes to synthesise similar biologically active molecules. Such "man-made" molecules, produced by imitation and often by variation of the groups present in known substances, are the new and sometimes improved drugs. There are many examples of how the chemist has been able to improve on Nature by using as a model for his synthetic skill some medicinal substance which he has extracted from a plant. For instance, there is the new analgesic, alphaprodine (V), which can replace morphine (IV) or codeine (VI), as a chemical for the relief of pain. Alpha- prodine is synthetic and is analgesically more powerful than morphine, which is extracted from the opium poppy (Papaver somniferum L.). Alphaprodine was made in imitation of the structural pattern of the morphine molecule, according to a theoretical relationship established between structure and physiological action in the morphine molecule.

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Herbal remedies have been used by man for more than five thousand years. Perhaps in every country these traditional remedies have been evolved by a process of trial and error, and they include drugs of real value as well as many that are worthless. However, it was only about a hundred and fifty years ago, with the great development of the basic science of organic chemistry, that plants were first examined and their physiologically active constituents isolated in a pure state. Structural investigations of these pure plant drugs have been extremely valuable in suggesting general relationships between the architecture of a specific molecular type and its pharmacological behaviour. Here is a chemico-pharmacological relationship of interest to the West Indian reader. A blood-sugar lowering substance called hypoglycin A (VIII) has been found in the Jamaican ackee (Blighia sapida Koen.). It may be meta- bolised within the human body into the acid (VIII). Compare the molecule (VIII) with pent-4-enoic acid (IV) and the cyclobutyl compound (X). Like hypoglycin A, the molecules (IX) and (X), which have not been found in the ackee, show hypoglycaemic action. So it is conceivable that hypoglycaemia

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in animals may be associated in these molecules with the grouping (G=G) separated by two carbon atoms from the group (O = C- OH). Unfortunately, these simple molecules, (VII) to (IX), are unsatisfactory as anti-diabetes drugs because they produce undesirable side effects and allergies in treated cases. To develop better blood-sugar lowering drugs of this molecular type, the chemist may then synthesise new substances which incorporate, firstly, the basic chemical relationships found in (VII) to (IX) to be associated with hypoglycaemia, and secondly, such chemical groups as would free the new compounds from undesirable side effects. This requires the chemical combination of simple substances like (I) with other easily available molecules by the usual techniques of heating, mixing, irradiation and electrical treat- ment. Then all that remains is for the pharmacologists and the clinicians to test the resulting chemical combinations in test animals and humans.

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Such a process was performed in the development of alphaprodine (V) from morphine (IV). This process will be repeated again and again for this and other drug types as structural elucidations come to be performed on the wide variety of still unknown molecular types which are elaborated by plants.

The methods of chemotherapy involve the selective destruction by chemical agents of parasites which produce within the host such ailments as malaria and sleeping sickness. This developing science has shown us that living microbial parasites may acquire resistance to a particular drug which was able to destroy their parents. This is an important problem. A new drug shows high promise in the treatment of an infectious disease; but, after a time it becomes very much less effective. The reason? Perhaps this phenomenon

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points to some factor inherent in the nature of biological response of the living parasites to changes in their environment. However, it is a warning against complacency. It underlines the need for us to be ever in quest of new drugs to replace those which lost their efficacy. This is a technical reason in favour of the existence of a West Indian institution which may join in the battle against disease-carrying germs that are even so much more prevalent in the tropics. Further, this kind of organisation should tend to curb the unfortunate one-way movement of scientific talent towards the more highly industrialised countries.

There must be other practical reasons for the initiation of a vigorous search in our flora for that safe drug from the Caribbean, which could protect human flesh from the effects of radioactive fall-out!

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