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Saturday, September 18, 2010

ORIGIN AND SOURCES OF HOMOEOPATHIC DRUGS :Plant Source [Plant Source]:

Posted by Drdevendra Kumar munta
-Sumit Goel.

Plant drugs can be arranged for study under the following headings.

* Morphological - drugs are divided into groups such as leaves, flowers, fruits, seeds, herbs, entire organism, woods, barks, rhizomes, roots, extracts, gums, resins, oils and fats.

* Taxonomical - on the basis of accepted system of botanical classification, drugs are arranged according to the plants from which they are obtained: phylum, order, family, genera, and species.

* Chemical or Biogenetic - the important constituents like alkaloids, glycosides, volatile oils or their biosynthetic pathways form the basis of classification of drugs.

* Pharmacological or Therapeutic - involves grouping of drugs according to pharmacological action of their most important constituent or their therapeutic use.

MORPHOLOGICAL CLASSIFICATION OF PLANT DRUGS Plants consist of several parts. They may be classified according to their functions.

(a) Vegetative parts - are responsible for carrying out the activities of maintenance, growth and repair of the plant: - leaves, stems and roots.

(b) Reproductive parts - are responsible for production of new plants and maintenance of species: - flowers, fruits and seeds.

A. WHOLE PLANT

(i) Without roots - Alfalfa, Lobelia inflata, Mentha piperita, Ocimum sanctum, Ranunculus sceleratus

(ii) With roots - Acalypha indica, Aconitum napellus, Aethusa cynapium, Arnica montana, Belladonna, Chamomilla, Chelidonium majus, Cineraria maritima, Conium, Drosera, Dulcamara, Euphrasia, Gnaphalium, Hydrocotyle, Hyoscyamus niger, Hypericum, Ledum palustre, Millefolium, Pulsatilla nigricans, Rheum, Ruta graveolens, Spigelia, Stramonium, Urtica urens, Vinca minor

B. ROOTS

The axis of the plant going vertically downwards in the soil is the root. Roots may be true roots or adventitious or tuberous roots. Leaves and buds are absent in roots and no leaf scars are found on the surface of roots.

(i) Fresh - Abroma augusta, Aralia racemosa, Artemisia vulgaris, Arum triphyllum, Bryonia alba, Cicuta virosa, Jalapa, Oenanthe crocata, Paeonia officinalis, Phytolacca, Raphanus

(ii) Dried - Calotropis, Ipecacuanha, Ratanhia, Rauwolfia serpentina, Senega, Sumbul

(iii) Aerial - Ficus indica

(iv) Root and rhizome - Aletris farinosa

C. STEMS

(i) Only stem - Cactus grandiflorus

(ii) Stem with leaves - Clematis erecta

(iii) Rhizome - It is a sub-terannean stem growing vertically, horizontal or in oblique direction. Surface of the rhizome bears scale-leaves and sometimes buds may be present in their axils. Rhizome has nodes and internodes and its lateral and lower surface bears thin adventitious roots.

- Cimicifuga racemosa, Collinsonia canadensis, Gelsemium, Helleborus niger, Podophyllum peltatum, Sanguinaria canadensis, Veratrum album, Veratrum viride (iv) Corm - It is a short, thickened, fleshy sub-terranean stem and contains buds.

- Colchicum autumnale, Crocus sativus

(v) Bulb - It is a sub-terranean bud whose surrounding leaves have become fleshy.

- Allium cepa, Allium sativum

D.LEAVES

Leaves are the lateral appendages of the stem and contain chlorophyll.

(i) Dried - Coca, Eucalyptus, Tabacum

(ii) Fresh - Aegle folia, Digitalis purpurea, Jaborandi, Kalmia latifolia, Rhus toxicodendron

E. FLOWERS

Drugs used as flowers may be entire inflorescence or entire flowers or petals or stigmas.

Flowers may be in a bud state or fully developed flowers.

(i) Flower bud - Prunus spinosa

(ii) Stigma - Crocus sativus

(iii) Flowering heads - Cannabis sativa, Cina, Helianthus annus, Calendula (with leaves)

F. FRUITS

(a) Fleshy fruits - If the pericarp is soft and succulent, fruit is called fleshy fruit.

(i) Berry - It is a many seeded fleshy fruit that develops from mono-carpellary or poly-carpellary, superior or inferior ovary.

- Agnus castus, Crataegus oxyacantha, Sabal serrulata, Viscum album (fresh leaves and berries)

(b) Dried fruits

(i) Nuts - It is a single celled and single seeded fruit that develops from a superior bi-carpellary or poly-carpellary ovary, having a hard and woody polycarp.

- Aesculus hippocastanum

(ii) Pods - Dolichos pruriens

(iii) Others - Capsicum annum, Terminalia chebula

G. SEEDS

(i) Fresh - Avena sativa, Cucurbita pepo, Ignatia amara, Syzygium jambolanum

(ii) Dried - Carduus marianus, Cedron, Cocculus indicus, Coffea cruda, Nux moschata, Nux vomica, Sabadilla, Staphysagria

H. BARK Barks consist of the external tissues of stem or root of dicotyledon plants lying outside the cambium.

(a) Outer bark

(i) Fresh - Abies canadensis, Salix nigra, Viburnum opulus

(ii) Dried - Alstonia scholaris, Condurango, Cinchona officinalis, Mezereum

(b) Inner bark - Cinnamomum, Fraxinus americana

(c) Bark of root

(i) Fresh - Baptisia tinctoria, Berberis vulgaris, Hamamelis virginica

(ii) Dried - Gossypium herbaceum

(d) Bark of root and stem - Robinia pseudocacia

(e) Bark of trees - Azadirachta indica, Jonosia asoka, Terminalia arjuna

I. WOOD

Wood consists of tissues of stem or root of dicotyledon plants lying internal to cambium and contains secondary xylem and primary xylem. - Santalum album

J. EXTRACTS AND PLANT CONSTITUENTS

(i) Juices - Aloe socotrina, Anacardium occidentale, Opium

(ii) Resins - Abies nigra

(iii) Gum-resins - Asafoetida, Ammoniacum (gum)

(iv) Balsams - Balsamum peruvianum

(v) Volatile oils - Oleum santali

(vi) Fixed oils - Oleum crotonis

(vii) Alkaloids - Aconitine, Atropine, Codeine, Morphine, Narcotinum, Nicotinum, Pilocarpinum, Quinidine, Strychninum

(viii) Glycosides - Adonidin, Digitalin, Phlorizinum, Sanguinarin, Saponinum

(ix) Resinoids - Aletrin, Apocynin, Asclepin, Caulophyllin, Dioscorin, Podophyllin, Xanthoxylin

TAXONOMIC CLASSIFICATION OF PLANT DRUGS

- Plant drugs can be classified on the basis of accepted system of classification, whereby they are grouped into families, on the basis of certain common characteristics.

* CRYPTOGAM - An older term used to designate that part of the plant kingdom not producing flowers or seeds.

1. DIVISION THALLOPHYTA

* ALGAE - Fucus vesiculosus

* FUNGI - Agaricus campestris, Agaricus emeticus, Agaricus muscaris, Boletus laricis, Bovista, Ustilago, Secale cornutum (nosode)

* LICHENS - Sticta pulmonaria, Usnea barbata

2. DIVISION BRYOPHYTA

* Polytrichum juniperinum 3. DIVISION PTERIDOPHYTA

* EQUISETINAE - Equisetum

* FILICINAE - Filix mas

* LYCOPODINAE - Lycopodium clavatum

* PHANEROGAM - An older term used to designate that part of the plant kingdom producing flowers and seeds.

1. CLASS GYMNOSPERMAE

* CONIFERAE - Abies canadensis, Abies nigra, Pinus sylvestris, Juniperus communis, Sabina, Thuja

* TAXACEAE - Taxus baccata

2. CLASS ANGIOSPERMAE

(A) MONOCOTYLEDONS - plants, the embryo of which has one cotyledon.

* AMARYLLIDACEAE - Agave americana, Narcissus

* ARACEAE - Acorus calamus, Arum dracontium, Arum maculatum, Arum triphyllum, Caladium seguinum, Pothos foetidus

* DIOSCORIACEAE - Dioscorea villosa, Tamus communis

* GRAMINEAE - Anantherum, Anthoxanthum odoratum, Arundo, Avena sativa, Cynodon dactylon, Triticum repens, Zea mays

* HAEMORDORACEAE - Aletris farinosa, Lachnanthes

* IRIDACEAE - Iris tenax, Iris versicolor, Crocus sativus

* LEMNACEAE - Lemna minor

* LILIACEAE - Agraphis nutans, Aletris farinosa, Allium cepa, Allium sativum,Aloe socotrina, Asparagus officinalis, Colchicum autumnale, Convallaria, Helonias dioica, Lilium tigrinum, Ornithogalum, Paris quadrifolia, Sabadilla, Sarsaparilla, Squilla, Veratrum album, Veratrum viride, Yucca filamentosa

* MELANTHACEAE - Helonias, Sabadilla, Yucca filamentosa

* ORCHIDACEAE - Cyprepedium, Spiranthes

* PALMAE - Areca catechu, Musa, Sabal serrulata

* SMILACEAE - Sarsaparilla, Trillium pendulum

* ZINGIBERACEAE - Curcuma longa, Zingiber officinalis

(B) DICOTYLEDONS - Plants, the embryo of which has two cotyledons.

* ANACARDIACEAE - Anacardium occidentale, Anacardium orientale, Comocladia, Rhus aromatica, Rhus glabra, Rhus toxicodendron, Rhus venenata

* APOCYNACEAE - Alstonia, Apocynum cannabinum, Aspidosperma, Holarrhena antidysenterica, Oleander, Quebracho, Rauwolfia serpentina, Strophanthus, Vinca minor

* ARALIACEAE - Aralia racemosa, Ginseng, Hedera helix

* ARISTOLOCHIACEAE - Aristolochia, Asarum canadense, Asarum europaeum

* ASCLEPIADACEAE - Asclepias incarnata, Asclepias tuberosa, Calotropis gigantea, Condurango, Gymnema sylvestre, Tylophora indica

* BERBERIDACEAE - Berberis aquifolium, Berberis vulgaris, Caulophyllum, Podophyllum peltatum

* CACTACEAE - Anhalonium, Cactus grandiflorus, Cereus bonaplandi, Opuntia

* CANNABINACEAE - Cannabis indica, Cannabis sativa, Lupulus

* CAPRIFOLIACEAE - Sambucus canadensis, Sambucus nigra, Symphoricarpus racemosus, Viburnum opulus, Viburnum prunifolium

* CARYOPHYLLACEAE - Saponaria officinalis, Stellaria

* CHENOPODIACEAE - Chenopodium anthelminticum, Beta vulgaris

* CISTACEAE - Cistus canadensis

* COMPOSITAE - Abrotanum, Absinthium, Arnica montana, Artemisia vulgaris, Bellis perennis, Blumea odorata, Brachyglottis repens, Calendula officinalis, Carduus marianus, Chamomilla, Cina, Cineraria, Echinacea, Erechthites, Erigeron, Eupatorium perfoliatum, Eupatorium purpurium, Gnaphalium, Grindelia, Helianthus annus, Inula, Lactuca virosa, Lappa major, Millefolium, Parthenium, Pyrethrum, Senecio aureus, Silphium laciniatum, Solidago, Tanacetum vulgare, Taraxacum, Tussilago farfara, Veronia anthelmintica, Wyethia

*CRUCIFERAE - Brassica, Cochlearia armoracia, Iberis, Raphanus sativus,

* Sinapis alba, Sinapis nigra, Thlaspi bursa pastoris

* CUCURBITACEAE - Bryonia alba, Cephalandra indica, Citrullus colocynthis, Cucurbita pepo, Elaterium, Luffa amara, Luffa bindal, Momordica, Trichosanthes dioica

* DROSERACEAE - Drosera rotundifolia

* ERICACEAE - Chimaphila, Gaultheria, Kalmia latifolia, Ledum palustre, Oxydendron, Rhododendron, Uva ursi

* ERYTHROXYLAE - Coca

* EUPHORBIACEAE - Acalypha indica, Cascarilla, Croton tig, Euphorbium, Hura brasiliensis, Jatropha curcas, Mancinella, Mercurialis perennis, Ricinus communis, Stillingia sylvatica

* GENTIANACEAE - Gentiana cruciata, Gentiana lutea, Menyanthes, Swertia chirata

* HAMAMELIDACEAE - Hamamelis virginica

* HYPERICACEAE - Hypericum perforatum

* JUGLANDACEAE - Juglans cinerea, Juglans regia

* LABIATAE - Coleus aromaticus, Collinsonia, Leucus aspera, Lycopus virginicus, Mentha piperita, Ocimum canum, Ocimum gratissimum, Ocimum sanctum, Origanum, Salvia officinalis, Scutellaria, Teucrium marum virum

* LAURACEAE - Cinnamonum camphora, Cinnamonum zeylanicum

* LEGUMINOSEAE - Alfalfa, Baptisia tinctoria, Caesalpinia bonducella, Copaiva, Desmodium gangeticum, Dolichos, Haematoxylon, Indigo, Jonosia asoka, Lathyrus sativus, Melilotus, Mimosa, Physostigma, Piscidia, Psoralea corylifolia, Ratanhia, Robinia, Senna, Tongo, Trifolium pratense

* LOBELIACEAE - Lobelia cardinalis, Lobelia inflata

* LOGANIACEAE - Gelsemium, Ignatia amara, Nux vomica, Spigelia, Upas tiente

* LORANTHACEAE - Viscum album

* MALVACEAE - Gossypium herbaceum, Hibiscus rosa-sinensis

* MELIACEAE - Amoora rohituka, Azadirachta indica, Guarea trichiloides

* MENISPERMACEAE - Cocculus indicus, Menispermum, Pareira brava, Tinospora cordifolia

* MORACEAE - Ficus bengalhensis, Ficus elastica, Ficus religiosa

* MYRICACEAE - Myrica cerifera

* MYRISTICACEAE - Myristica sebifera, Nux moschata

* MYRTACEAE - Angophora, Cajuputum, Eucalyptus globulus, Eugenia jambos, Myrtus communis, Syzygium jambolanum

* OLEACEAE - Chionanthus virginica, Fraxinus americana, Nyctanthes arbortristis

* PAPAVERACEAE - Chelidonium majus, Opium, Sanguinaria

* PHYTOLACCACEAE - Phytolacca decandra

* PIPERACEAE - Cubeba, Piper longum, Piper methysticum, Piper nigrum, Saraca indica

* POLYGONACEAE - Fagopyrum, Polygonum punctatum, Rheum, Rumex

* PRIMULACEAE - Anagallis arvensis, Cyclamen, Primula veris

* RANUNCULACEAE - Aconitum lycotonium, Aconitum napellus, Actaea spicata, Adonis vernalis, Caltha palustris, Cimicifuga, Clematis erecta, Helleborus niger, Hydrastis, Paeonia, Pulsatilla nigricans, Ranunculus acris, Ranunculus bulbosus, Ranunculus sceleratus, Staphysagria

* RHAMNACEAE - Cascara, Ceanothus americanus, Rhamnus californica, Rhamnus catharticus, Rhamnus frangula

* ROSACEAE - Amygdalus amara, Crataegus, Laurocerasus, Prunus padus, Prunus spinosa, Prunus virginiana, Pyrus, Quillaya saponaria

* RUBIACEAE - Cinchona officinalis, Coffea, Ipecacuanha, Mitchella repens

* RUTACEAE - Aegle marmelos, Angustura, Atista radix, Barosma, Citrus limon, Citrus vulgaris, Jaborandi, Ptelea trifolia, Ruta graveolens, Xanthoxylum

* SALICACEAE - Populus candicans, Populus tremuloioes, Salix nigra, Salix purpurea

* SANTALACEAE - Santalum album

* SAPINDACEAE - Aesculus glabra, Aesculus hippocastanum, Guarana, Paullinia pinnata

* SCROPHULARIACEAE - Chelone glabra, Digitalis, Euphrasia, Gratiola, Leptandra, Linaria vulgaris, Scrophularia nodosa, Verbascum thapsus

* SIMARUBACEAE - Ailanthus glandulosa, Cedron, Quassia

* SOLANACEAE - Belladonna, Capsicum, Datura arborea, Duboisia, Dulcamara, Hyoscyamus, Lycopersicum esculentum, Mandragora, Solanum carolinense, Solanum nigrum, Solanum xanthocarpum, Stramonium, Tabacum, Withania somnifera

* THYMELIACEAE - Daphne indica, Mezereum

* UMBELLIFERAE - Aethusa cynapium, Ammoniacum, Anthamantha oreoselinum, Apium graveolens, Asafoetida, Branca ursina, Cicuta, Conium maculatum, Eryngium aquaticum, Hydrocotyle, Oenanthe crocata, Pastinaca, Petroselinum, Phellandrium, Pimpinella, Sumbul

* URTICACEAE - Urtica urens

* VALERIANACEAE - Valeriana officinalis

* VERBENACEAE - Agnus castus, Clerodendron infortunatum, Verbena officinalis

* VIOLACEAE - Viola odorata, Viola tricolor

* ZYGOPHYLACEAE - Guaiacum, Tribulus

COLLECTION AND PRESERVATION OF PLANT DRUGS

GUIDELINES FOR COLLECTION AND PRESERVATION OF CRUDE PLANT DRUGS

1. Collection of drug substances should be under the supervision of a qualified and experienced Botanist having a specialized knowledge of botany, pharmacognosy and taxonomy. He should also, preferably, have a basic knowledge of homoeopathy and homoeopathic pharmacy.

2. All vegetable products are to be collected fresh, as far as possible.

3. All vegetable plant drugs, in the crude form, should be gathered from habitats to which they are indigenous. Wild plants are more effective and possess more medicinal value than those cultivated in gardens. Plants having the greatest degree of medicinal activity are those found in their natural places of growth.

4. Only healthy, fresh and well-developed plants are selected. The plants should be perfect, vigorous and those that are regularly formed. 5. Plants having acquired a woody consistency through old age need to be discarded. The plants should be free from dust, worms and insects. Worm-eaten plants, plants spoilt by dirt and mud, all sickly looking, withered, decayed plants and roots and plants with some discolouration, abnormal odour, disease or any other sign of deterioration should be discarded. 6. Plants should be collected in fine, sunny, dry weather in the early morning just after the disappearance of the morning dew. They should not be collected after heavy rainfall and during excessive heat of the day.

7. Cleansing should be done carefully so that any part of it is not eroded. Large amount of water should not be used for washing.

8. Exotic drugs should never be imported in powder form and without proper identification of their genuineness. They are to be obtained from a reputed firm, preferably in their natural form or state and proper identification should be carried out before using them in the preparation of the mother tincture. 9. For exporting vegetable products to foreign countries, they should be tied in loose bundles and then hanging in the shade away from direct sunlight, rain, etc. They should be packed loosely in ordinary cases or botanical boxes or vasculums.

10. Drugs can be kept fresh for a long time by keeping them in a cold storage. Due precautions should be taken to preserve its freshness during transport and storage.

11. Odorous substances should be kept in separate vessels so that the peculiar odour of such drugs may not be transmitted to others.

"The other exotic plants, barks, seeds and roots that cannot be obtained in the fresh state, the sensible practitioner will never take in the pulverized form on trust, but will first convince himself of their genuineness in their crude, entire state before making any medicinal employment of them. (Aphorism 268)"

"The entire crude vegetable substances, though perfectly dry, yet contain a certain quantity of moisture, which does not prevent the unpulverized drug from remaining in a dry state. The animal or vegetable substance, which in its entire state was perfectly dry, furnishes, when finely pulverized, a somewhat moist powder. For preservation, this is best effected by spreading out the powder in a flat tin saucer with a raised edge, which floats in a vessel full of boiling water. By means of stirring it about, it is dried to such a degree that all the small atoms of it like dry fine sand are easily separated from each other and are easily converted into dust. In this dry state, the fine powders may be kept forever uninjured in well-corked and sealed bottles, without ever being injured by mites or mould; and they are best preserved when the bottles are kept protected from the daylight. If not shut up in air-tight vessels and not preserved from the access of the light of the sun and day, all animal and vegetable substances in time gradually lose their medicinal power more and more, even in the entire state, but still more in the form of powder. (Footnote 145, aphorism 268)"

The fineness of dried vegetable drugs and other organic substances used in making tinctures is designated according to the following classification, all of which must pass through a sieve. (HPUS)

a Coarse powder (20) - standard mesh screen 20 meshes to the inch

b Moderately coarse powder (40) - standard mesh screen 40 meshes to the inch

c Fine powder (60) - standard mesh screen 60 meshes to the inch

d Very fine powder (80) - standard mesh screen 80 meshes to the inch

As regards plants, the parts that are used in the preparation are to be collected at a specific time, as directed, as they possess their active principles at the optimum levels at such a time.

WHOLE PLANT:

In flowering season, when it is partly in flower and partly in bud during sunny weather. They should be carefully cleansed by shaking, brushing or gentle rubbing; washing with profuse water should be avoided.

ROOTS:

ANNUALS: Dug out early in autumn, since they die after ripening of seeds. In autumn, the plant is inactive. Its vegetative processes have ceased and thus it contains maximum percentage of active constituents.

BIENNIALS: In the spring of the second year.

PERENNIALS: In the second or third year, before they develop woody fibres.

Roots are to be collected by cutting just under the stem. Roots should be cleaned without using much water. They should be free from moulds and woody appearances. After collection of fresh material they should be processed as early as possible to avoid deterioration.

STEMS:

After development of leaves.

WOOD:

In early spring or late in autumn before the juices are not exhausted and also from mature young trees or tree-like shrubs.

BARKS:

RESIN: In early spring, at the time of development of leaves and blossoms.

NON-RESIN: Late in autumn from young vigorous trees. Bark is usually collected by making suitable longitudinal and transverse incisions on the stem or root of the plant. In this season, cambium is very active and since its cell walls are very thin, bark gets easily separated at cambium. Barks may be collected by felling, uprooting or coppicing.

HERBS:

When they are fully developed, should be cut just above roots.

YOUNG SHOOTS:

In spring, when the whole plant is in full vigour.

LEAVES:

Just before and during early part of flowering time. Leaves of biennial plants are collected in spring of second year as soon as the flowering stems begin to shoot. Leaves are collected during this period, as in this season the plant is very active, the sap movement and photosynthetic activity are maximum and leaves contain maximum percentage of active constituents. As the moisture decreases their constituents, they are collected in dry weather. Leaves are packed and stored in airtight containers at low temperature, protected from light and moisture.

TWIGS:

Of present year's growth only.

FLOWERS:

Partly in bud and partly in blossom, in dry weather. Flowers are collected about the time of pollination in dry weather and in the forenoon after few hours of sunshine when dew has dissipated. Flower drugs should be dried in shade. If dried in sun, they become bleached and paler.

BULBS:

As soon as they mature when the leaves begin to decay.

FRUITS AND SEEDS:

When they are fully ripe. Succulent fruits, seeds or berries should be used while fresh. Only dried fruits, seeds or berries may be stored in well-closed glass container.

BACHFLOWER REMEDIES.

This mode of treatment was discovered by Dr. Edwards Bach. He sought for remedies in the plant world that would restore vitality to the sick and ailing.

The remedies are prepared from the flowers of wild plants, bushes or trees.

1. Agrimony

2. Aspen

3. Beech

4. Centuary

5. Cerato

6. Cherry Plum

7. Chestnut Bud

8. Chicory

9. Clematis

10. Crab Apple

11. Elm

12. Gentian

13. Gorse

14. Heather

15. Holly

16. Honeysuckle

17. Hornbeam

18. Impatiens

19. Larch

20. Mimulus

21. Mustard

22. Oak

23. Olive

24. Pine

25. Red Chestnut

26. Rock Rose

27. Rock Water

28. Seleranthus

29. Star of Bethelehem

30. Sweet Chestnut

31. Vervain

32. Vine

33. Walnut

34. Water Violet

35. White Chestnut

36. Wild Oak

37. Wild Rose

38. Willow.

Preparation of bach flower remedies The remedies are made by two methods the first through the action of sun and second by boiling. The flowering heads of the plant are placed on the surface of a small glass bowl filled with pure spring water. The bowl is then left in the sunshine for 3 hours during which time the water becomes impregnated with healing properties of plant. The flowering heads having transfered their vital energy to the water, are then discarded. The water is then preserved in alcohol (brandy) This is the mother tincture. This is how twenty of the flower remedies are being prepared.

The other eighteen are made by boiling and those prepared by this method are mostly the trees.

short length of twigs filled with the flower are collected and boied in pure spring water for half an hour and then left to cool. The twigs with their leaves and flowers are then discarded.

The next stage in the preparation of the remedies is to dilute the mother tincture into a further quantity of brandy and is now termed as stock preparation. This is considered as a concentrated remedy and requires further dilution before administration.

PHYTOCHEMISTRY - ACTIVE PRINCIPLES OF PLANT DRUGS

Phytochemistry is the chemistry of plants or chemical constituents of plants. It is the chemistry of natural plants used as drugs.

The constituents of a plant may be active or inactive. The inactive constituents are structural constituents of cell wall like cellulose, lignin or reserve constituents of plants like starch, sugars or proteins. The active constituents are secondary metabolites like alkaloids, glycosides, oils, tannins, etc. The plant, during biosynthesis produces carbohydrates, fats and proteins and these are called the primary metabolites. The secondary products of the plant are formed from the primary products and are deposited in specific parts of the plant and are called the secondary metabolites.

The phytochemical property of each plant species is unique and specific to it. The constituents and their composition depend upon the species of the plant, their habitat, the soil in which they grow and the season. There is also a variation in the composition of these constituents in the different parts of the plant. Hence, in cultivation, attention is paid to the selection of proper strain of seeds, type of soil, optimum climatic factors like light, temperature, elevation, rainfall and plant growth factors. Drugs are collected during definite season, time of the day and in special condition, at a definite stage of development. Hence, the part used for the preparation of the medicine and the time and mode of collection is specified in the pharmacopoeia.

The active principles of a drug are the potent constituents of the drug that is individual to the drug and are responsible for the pharmacodynamic action of the drug.

HOMOEOPATHY ACCEPTS A DRUG WITH ITS ENTITY AND TOTALITY WITHOUT ATTEMPTING TO SEPARATE A DRUG INTO ITS SPECIFIC CHEMICAL CONSTITUENTS.

CARBOHYDRATES

* Carbohydrates are the primary products of photosynthesis.

* They are the structural or skeletal substances of plants (cellulose).

* Precursors of secondary constituents like alkaloids, glycosides, etc.

* They have a general formula Cn(H2O)n.

* Carbohydrates are mainly classified into a) sugars, and b) non-sugars.

Honey - A mixture of glucose and fructose. Sucrose, dextrin, volatile oil and pollen grains are also present in honey.

Starch - Zea mays, Avena sativa, Solanum tuberosum, Ipomoea

Gums - Gums are plant exudates produced for the protection of the plant when it is injured. Gums are characteristic of certain natural orders like Leguminosae, Rosaceae, Combretaceae and Sterculiaceae. - Gum Acacia, Sterculia, Ammoniacum gummi.

Mucilage - Mucilages are normal products and are prepared without injury to the plant. - Plantago, Aegle marmelos.

GLYCOSIDES

* Glycosides are non-reducing organic substances, which on hydrolysis yields an aglycone, usually known as genin and sugar.

* If the sugar is glucose, it is called as 'glucoside'.

* Glycosides can be hydrolyzed by enzyme, acid, and alkali or sometimes only with moisture.

* Glycosides are colourless, crystalline or amorphous solid substances. They are soluble in water and alcohol, but insoluble in ether and chloroform.

* The name of all glycosides end in "in".

EXAMPLES -

* Rheum - emodin, aloe-emodin, rhein

* Aloes - aloin

* Digitalis - digitoxin, gitoxin, gitaloxin, purpurea glycosides A and B, digoxin, digitalin, digiconin.

* Mezereum - daphin.

* Cinchona - quinovin.

* Aesculus hippocastanum - aesculetin

* Ruta graveolens - rutin.

* Thuja occidentalis - thujin, thujetin, thujenin.

* Sambucus nigra: sambunigrin

Saponins - Saponins are plant glycosides with distinctive property of frothing. Saponins are non-crystalline and dissolve in water with colloidal solutions.

* Dioscorea villosa: diosgenin, dioscin

* Digitalis: digitonin

* Aesculus hippocastanum: aescin

* Calendula officinalis: calendula-saponin

* Cyclamen: cyclamin

* Saponaria: quillaia-saponin

TANNINS

* Tannins constitute a large group of complex, organic, non-nitrogenous, phenolic compounds of high molecular weight.

* They possess the property to 'tan', i.e. to convert hide and skin into leather.

* Tannins are soluble in water and alcohol, have astringent taste, precipitate proteins and produce acidic reaction.

EXAMPLES -

* Hydrolyzable tannins - Rheum, Hamamelis, Granatum, Eucalyptus

* Condensed tannins - Cinnamon, Cinchona, Hamamelis, Ratanhia, Filix mas, Cocoa, Areca catechu

* Pseudotannins - Rheum, Areca catechu, Nux vomica, Ipecacuanha

RESINS

* Resins are plant exudates, except shellac or lac, which the lac-insect prepares from plant juices.

* Resins are amorphous, transparent or translucent solids, semi-solids or liquid substances.

* Resins when heated soften, melt and form clear adhesive fluids.

* Resins are insoluble in water but soluble in organic solvents like alcohol, volatile oils and fixed oils.

* If the resins are produced as normal products of metabolism without injury to the plant, the resins are called as normal or physiological resins. E.g. Copaiva.

* As a result of wound or injury, the plant gets a shock and in newly developed secondary xylem and bark, a large number of resin ducts are formed. Resin produced in this way is called pathological resin. E.g. Tolu balsam.

* Resins associated with volatile oil are called oleo-resins - Eg. Copaiva, Aspidium filix-mass (male fern).

* Resins in association with both volatile oil and gum are called oleo-gum-resins.

* If the resins contain benzoic acid and / or cinnamic acid and / or their esters, they are called balsams. Balsams are semi-fluid and fragrant.

* Glyco-resins - Ipomoea.

* Lignan - Podophyllum: podophyllotoxin, ?-peltatin, ?-peltatin.

* Miscellaneous resins - Cannabis sativa: cannabidiol, cannabidolic acid, cannabigerol.

- Colocynthis: cucurbitacin.

- Zingiber, Curcuma longa, Capsicum.

* Balsams - Balsamum tolutanum, Balsamam peruvianum.

ALKALOIDS

* Alkaloids are organic nitrogenous substances, more or less alkaline in action and are the secondary metabolites of a plant.

* Alkaloids always contain carbon, hydrogen and one or more than one nitrogen, mostly oxygen and sometimes sulphur.

* The nitrogen in the alkaloid imparts basic properties, hence the term plant-alkali, alkali-like or 'alkaloid'.

* The salts of alkaloids with acids are soluble in water but insoluble in organic solvents. These differences in solubility are utilized for extraction, isolation, purification and assay of alkaloids.

* Paper and thin layer chromatography is used for identification, separation, isolation and assay of alkaloids.

* Alkaloids are active principles of many plants.

EXAMPLES -

* Hyoscyamus niger: l-hyoscyamine, traces of hyoscine.

* Belladonna: l-hyoscyamine, atropine, apoatropine, traces of hyoscine, scopolamine

* Stramonium: hyoscyamine, hyoscine.

* Coca: cocaine, cinnamyl cocaine.

* Cinchona: cinchona bark contains about 25 alkaloids of which the main crystalline alkaloids are quinine, quinidine, cinchonine and cinchonidine.

* Alkaloids are in combination with quinic acid and cinchotannic acid.

* Ipecacuanha: emetine, cephaeline, psychotrine.

* Opium: Opium contains more than 30 alkaloids of which the important ones are morphine, codeine, thebaine, papaverine, narcotine and narceine. Alkaloids of opium are in combination with meconic acid.

* Berberidaceae family: hydrastine, berberine

* Secale cornutum: ergometrine, ergotamine, ergosine, ergocristine, ergocryptine, ergocornine.

* Nux vomica: strychnine, brucine, vomicine, pseudostrychnine. Alkaloids are combined with chlorogenic acid.

* Conium maculatum: coniine

* Tabacum: nicotine

* Aconitum napellus: aconitine, benzoylaconine, aconine, hypoaconitine, mesaconitine, napelline, neopelline.

* Colchicum autumnale: colchicine, demecolcine.

* Coffea: caffeine

VOLATILE OILS

* Volatile oils are odorous constituents of plants.

* They are liquid, lipophile, and volatile with a characteristic smell.

* Volatile oils volatize or evaporate when exposed to atmosphere at an ordinary temperature.

* They are also called as essential oils as they are essences or concentrated constituents of plants.

* Volatile oils are nearly insoluble in water, but soluble in alcohol and ether.

* Volatile oils are present in entire plant or almost in any part of the plant as leaf, bark, seed, fruit, wood and sub-terranean parts.

* They are characteristic of certain orders such as Labiatae, Rutaceae, Myrtaceae, Lauraceae, Piperaceae and Zingiberaceae.

EXAMPLES

* Pinus species : Turpentine oil

* Mentha piperita : Peppermint oil

* Coriandrum sativum : Coriander oil

* Camphora : Camphor

* Mentha spicata : Spearmint oil

* Nux moschata : Nutmeg oil

* Eucalyptus globulus : Eucalyptus oil

* Chenopodium : Chenopodium oil

* Santalum album : Sandalwood oil

Certain flowers like orange and rose must be used fresh. Dry substances such as sandalwood, cinnamon bark should be macerated with water before being subjected to distillation.

FIXED OILS, FATS AND WAXES

* Fixed oils and fats, obtained from plants, differ only as regards their melting point but chemically they belong to the same group.

* If a substance is liquid at 15.5? to 16.5?, it is called fixed oil and if it is solid or semi-solid at the above temperature, it is called fat.

* Fixed oils and fats are insoluble in water and are immiscible with it.

* If a small quantity is placed on paper they produce a permanent translucent stain on the paper and consequently they are called fixed oils.

* Fixed oils and fats are rich in calories and present in the seeds as reserve substances.

Waxes

Waxes have physical properties similar to fat and are solid, semi-solid or occasionally liquid. Chemically waxes are esters or mixture of esters of higher fatty acids and higher alcohol.

* Ricinus comunis: Castor oil

* Arachis hypogoea: Arachis oil

* Sesamum indicum: Sesame oil

* Croton tiglium: Croton oil

* Hydnocarpus: Hydnocarpus oil

SELF ASSESSMENT

* Discuss the morphological classification and collection of plant drugs with examples

* Discuss collection and preservation of plant drugs

* What is Active Principle? Discuss with examples

QUIZ 1. Which drug is prepared from the whole plant excluding roots

(a) Lobelia

(b) Lycopodium

(c) Rhus tox

(d) Allium cepa

2. Which drug is prepared from corm

(a) Aconite

(b) Sarsaparilla

(c) Thuja

(d) Colchicum autumnale

3. Which drug is prepared from gummy juice

(a) Opium

(b) Abies nigra

(c) Asafoetida

(d) Coffea cruda

4. The proper time for collection of the whole plant is

(a) After development of leaves

(b) In early spring

(c) In flowering season, partly in bud and partly in flower

(d) Early in autumn

5. Atropine is

(a) Saponin

(b) Alkaloid

(c) Resin

(d) Tannin

ANSWERS: 1 (a); 2 (d); 3 (a); 4 (c); 5 (b).

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