Plant sources of aroma chemicals and medicines in India
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Plant sources of aroma chemicals and medicines in India: Opportunities and challenges for the new millennium J. Thomas, Joy P.P., Samuel Mathew and Baby P. Skaria Aromatic and Medicinal Plants Research Station, Odakkali, Asamannoor Post, Ernalulam District Kerala – 683 549, Tel. 0484 658221 E-mail: amprs@ker.nic.in Introduction Aromatic and medicinal plants synthesise and preserve a variety of biochemical products, many of which are extractable and useful as chemical feed stocks or as raw material for various scientific investigations. Many secondary metabolites of plant are commercially important and find use in a number of perfumery, flavouring and pharmaceutical compounds. The characteristic property of the plant is due to a variety of complex chemical compounds and hence aromatic and medicinal plants are generally referred to as `natural bio-chemical factories’ or `chemical goldmines’. Not all these natural chemicals can be synthesised in the laboratory. Aromatic plants possess odorous volatile substances, which occur as essential oil, green exudate, balsam and oleoresin in one or more parts, namely, root, wood, stem, foliage, flower and fruit. The term essential oil is concomitant to fragrance or perfumes because these fragrances are oily in nature and they represent the essence or active constituents of the plants. They are called volatile or ethereal oils as they evaporate when exposed to air at ordinary temperatures. The world of essential oils has now come out from yesterday’s narrow definition of the status symbol of luxury to indispensable necessities of common man in every day life, from the cradle of infancy to the silence of grave. Aromatic temptations have even changed the course of world history and civilisations. Herbal ‘renaissance’ is happening globally and the herbal products today symbolise safety in contrast to the synthetics. Over three-quarters of the world population relies mainly on plants and plant extracts for health care. More than 30% of the entire plant species, at one time or other, were used for medicinal purposes. Chinese, Indian, Arabian and other traditional systems of medicines make extensive use of about 5000 plants. The demand and price of herbal products and essential oils are increasing consistently in the national and international markets due to strong pro-consumer movement. In the world of fragrance and flavour industry, essential oils contribute to about 17%. The extent of usage of essential oils is 55-60% for flavours in food industry, 15-21% for fragrances in perfumery/cosmetic industry, 10-20% as starting material for isolation of components, 5-10% as active substances in pharmaceutical preparations and 2-5% for natural products. USA, France and Germany are in the forefront of essential oil trade. It is estimated that the annual turn over of perfumery, cosmetic and flavour industry exceeds US $ 6 billion comprising more than 100 essential oils the world over. In India, the estimated production of perfumery raw material is around 5000t/annuum valued at Rs. 400 crores. The annual earning of foreign exchange from their export is around Rs. 130 crores. About 90% of India’s requirement of essential oils are met from indigenous production and the rest from import. India ranks 28 th in imports and 14th in exports in the global trade of essential oils. India’s contribution is only 1.1% in exports and 0.7% in import. The home demand for essential oils is projected at 15000 tonnes and the export targeted at 3400 tonnes. The production of spice oils and oleoresins during 1998-99 was 2625 t valued at Rs. 293 crores. It is estimated that world market for plant derived drugs may account for about Rs.2,00,000 crores. Presently, Indian contribution is less than Rs.2000 crores. The annual production of medicinal and aromatic plant’s raw material is worth about Rs.200 crores. This is likely to touch US $5 trillion by 2050. It has been estimated that in developed countries such as United States, plant drugs constitute as much as 25% of the total drugs, while in fast developing countries such as China and India, the contribution is as much as 80%. Thus, the economic importance of medicinal plants is much more to countries such as India than to rest of the world. These countries provide two third of the plants used in modern system of medicine Of the 18,000 native species found in India, 1500 species contain aromas. Only 65 of them have large and consistent demand in world trade and are hence cultivated. The estimated annual area under aromatic crops in India is more than 20,000 hectares with a production of 1,500 tonnes. The average productivity of essential oil crops is 75kg/ha. Spices are grown in India over 23 lakh ha with a production of 225 lakh tonnes per year and the foreign exchange earnings from export of spices is about 1200 crores. Major plant sources of essential oils and aroma chemicals are given in table1. Pepper, ginger, cardamom, saffron, clove, fenugreek, cumin seed and celery seed oils and oleoresins were primarily used for flavouring. The most traded essential oils are mints, basil, orange, clove leaf, citronella, lemongrass, sandal wood, eucalyptus, geranium, lavender, jasmine and tuberose. Essential oils of ginger, sandalwood, lemongrass, jasmine, tuberose etc. are exported from India to Russia, USA, France, Germany, Britain, Netherlands, Australia and Gulf countries, though `traditional oils’ like sandalwood and lemongrass are showing a downward trend. The internal requirements of oils of basil, sandalwood, cumin seed, dill seed, juniper, etc are fully met from indigenous production. However, lavender, patchouli, clove, nutmeg, geranium and rose oils are still imported from China, Brazil, Turkey, Bulgaria, Australia, Indonesia, Sri Lanka, etc for meeting the industrial requirement. India’s diversity is unmatched due to the presence of 16 different agro-climatic zones, 10 vegetation zones, 25 biotic provinces and 426 biomes (habitats of specific species). Nearly three fourth of the drugs and perfumery products used in the world are available in natural state in the country. Of the 2,50,000 higher plant species on earth, more than 80,000 are medicinal. Of these, about 15000-20000 species have good therapeutic value. However, only 7000-7500 species are used for their medicinal values by traditional communities. According to WHO, around 21,000 plant species have the potential of being used as medicine. 2 In India, drugs of herbal origin have been used in traditional systems of medicines such as Unani and Ayurveda since ancient times. The Ayurveda system of medicine uses about 700 species, Unani 700, Siddha 600, Amchi 600 and modern medicine around 30 species. The drugs are derived either from the whole plant or from different organs like leaves, stem, bark, root, flower, seed, etc. Some drugs are prepared from excretory plant products such as gum, resins and latex. Even the Allopathic system of medicine has adopted a number of plant-derived drugs. These form an important segment of the modern pharmacopoeia. Some important chemical intermediates needed for manufacturing the modern drugs are also obtained from plants (eg. diosgenin, solasodine, -ionone). These plants also continue to be an important source for new drugs. Plant-derived drugs offer a stable market world-wide. Plants, especially used in Ayurveda can provide biologically active molecules and blue prints for the development of modified derivatives with enhanced activity and /or reduced toxicity. The small fraction of flowering plants that have so far been investigated have yielded about 120 therapeutic agents of known structure from about 90 species of plants. Major plant sources of drugs are given in table 2. About 121 (45 tropical and 76 subtropical) major plant drugs have been identified for which no synthetic substitute is currently available. The important ones are given in table 3. The scientific study of traditional medicines, derivation of drugs through bio-prospecting and systematic conservation of the concerned medicinal plants is thus of great importance. Table 1. Major commercial sources of essential oils, oleoresins and aroma chemicals Item Botanical source Part used Chemical constituents Ajowan Trachyspermum Seed Thymol ammi Anise Pimpinella anisum Fruit Anethol, Methyl chavicol French Basil Ocimum basilicum Herb Hoary Basil Ocimum canum Herb American Basil Ocimum americanum Herb Camphor Basil Ocimum kilimanscharicum Ocimum tenuiflorm Leaf twig Clocimum Ocimum gratissimum Leaf twig Ocimum Ocimum viride Leaf twig Bergamot Citrus bergamia Fruit Camphor Wood, leaves Seed Seed Cinnamon Cinnamomum camphora Carum carvi Elettaria cardamomum Cinnamon verum Cassia Cinnamon cassia Bark, leaf Cedar wood Cedrus deodara Wood, saw dust, root Celery Apium graveolens Herb Limonene, Chamomile Matricaria chamomilla Cymbopogon winterianus C. nardus Herb Michelia champaka Eugenia caryophyllus Flowers Bud, leaf, Stem herb Chamazulene, azulene, farnesene Citronellal, citronellol, geraniol, geranyl acetate Citronellal, geraniol, citronellol, geranyl acetate Cinole, iso-eugenol, Eugenol, caryophyllene, humulene Linalool, ocimene, nerol, Holy/sacred Basil Caraway Cardamom Citronella Java Citronella Ceylon Champak Clove Clary sage Salvia sclarea Leaf twig Bark, leaf Grass Grass Methyl chavicol, methyl cinnamate, eugenol, linalool Linalool, camphor Methyl chavicol, citral, linalool Camphor Eugenol, methyl chavicol, methyl cinnamate, , linalool Eugenol, methyl chavicol, methyl cinnamate, linalool Thymol Linalyl acetate, linalol, limonene Safrole, piperitone, sabinene, eugenol Carvone, limonene Cineole, terpineol, limonene, cymene Eugenol, iso-eugenol, methyl eugenol Eugenol, iso-eugenol, methyl eugenol Cedrol, cedryl acetate uses Flavouringfoods, soft drinks, confectionery medicinal Flavouring soft drinks, confectionery, pharmaceuticals Pharmaceuticals, aroma chemicals, ointments, balms Pharmaceuticals, aroma chemicals, ointments, balms Pharmaceuticals, aroma chemicals, ointments, balms Pharmaceuticals, aroma chemicals, ointments, balms Pharmaceuticals, aroma chemicals, ointments, balms Pharmaceuticals, aroma chemicals, ointments, balms Pharmaceuticals, aroma chemicals, ointments, balms Citrus soft drinks flavour, ‘East Gray’ tea flavour Pharmaceuticals, incense, balms Flavouring Flavouring soft drinks, confectionery Seasoning, blending, natural flavours, pharmaceuticals Flavouring In perfumery for fixative effects and unique odour, soaps Flavouring foods, pharmaceuticals Flavouring foods, medicinal Perfumery chemicals, soap, cosmetics, flavouring Perfumery chemicals, soap, cosmetics, flavouring Perfumery, cosmetics Seasoning, blending, natural flavours, pharmaceuticals Flavouring soft drinks and 3 geraniol Linalool, -pinene, phellandrene, camphor liquors Flavouring of alcoholic drinks(eg. Gin), meat seasoning curry blends Seasoning curries, natural flavours Natural flavours, beverages, high grade perfumery Seasoning pickles, aroma chemicals, pharmaceuticals Disinfectants, germicides, soap, cosmetics Blending, medicinal Coriander Coriandrum sativum Herb, Seed Cumin Cuminum cyminum Seed Davana Artemisia pallens Dill Anethum sowa Flowering tops Herb, seed Eucalyptus Leaf twig Eucalyptus Eucalyptus citriodora Eucalyptus globulus Fennel Foeniculum vulgare Fruit Geranium Leaf twig Ginger Pelargonium graveolens Zingiber officinale Japanese mint Mentha arvensis Leaf twig Jasmine Jasmium officinale Flower Kacholam Kaempferia rotunda Rhizome Lavender Flower Grass Citral, linalool, geraniol Perfumery, soap, antiseptic, insecticides Lemon flavour, seasoning Linaloe Lavandula officianalis Cymbopogon flexousus Bursera delpechiana Benzyl acetate, linalool, linayl acetate, jasmone Ethyl-trans-p-methoxy cinnamate, pentadecane, cineole, carene, borneol Linalool, linalyl acetate Linalool, linalyl acetate, methyl heptanol Aroma chemicals, perfumery Marigolds Tagetes erecta Wood, berries, leaves Flowers Fragrance, cosmetics Nutmeg Myristica fragrans Fruit, seed, aril, leaf Tagetone, linalool, limonene, linalyl acetate Trimyristin, pinene, camphene, myristicin Orange sweet Palmarosa Citrus sinensis Cymbopogon martinii Patchouli Pogostemon cablin Fruit Flowering tops Leaf twig Citral Geraniol, geranyl acetate, citronellol, linalool Patchoulinol, caryophyllene Pepper Piper nigrum Seed Piperene Peppermint Mentha piperita Pimenta/Allspice Pimenta diocia Twig Leaf, fruit Menthol Eugenol, -pinene Rose Rosa damascena Flower Citronellol, geraniol, nerol, linalool Rosemary Sandalwood Rosmarinus officinalis leaves Santalum album Heart wood Spearmint Thyme Mentha spicata Thymus valgaris Herb Fruit Tuberose Vetiver Polyanthes tuberosa Vetiveria zizanoidea Flowers Roots Lemongrass Leaf twig Rhizome Cuminyl alcohol, cuminaldehyde Davanone, fenchyl alcohol, davanofuran Dillapiol Citronellal, citronellol, cineole, iso-pulegol Cineole, caryophyllene, camphene, sabinene, myrcene, Anethile, fenchone, Geraniol, citronellol, linalool, iso-menthone Zingiberene, zingerone, arcurcumene, farnesene Menthol, menthone, terpenes Pinene, cineole, linalool Santalol, santalene, curcumene, farnesene Thymol, cymene, linalool, limonene, cineole Geraniol, nerol, farnesol Vetiverol, vetinone, Seasoning, blending, natural flavours, pharmaceuticals In all kinds of scents Seasoning, blending, natural flavours, pharmaceuticals Flavouring tooth pastes, candies, ointments, tobacco, cough syrups Natural flavours Medicinal, preservation Cola flavour, meat seasoning, baking, natural flavours Lemon flavour, seasoning Flavouring tobacco, soap, high grade perfumery Flavouring non-alcoholic beverages, perfumes, soaps, cosmetics Seasoning, blending, natural flavours, pharmaceuticals Flavouring, medicinal Seasoning, blending, natural flavours Perfumery, cosmetics, flavouring soft drinks, pharmaceuticals Seasoning blends, medicinal Perfumery, soaps, detergents, shampoo Chewing gum, oral hygiene Aromatherapy, flavouring tooth pastes, candies, ointments, cough syrups Perfumery, cosmetics Perfumery, medicinal Ylang/Cananga Cananga oderata Flowers 4 eudesmol Cineole Paprika Capsicum annum Fruit Capsanthin Capsicum Capsicum friutenscens Curcuma longa Fruit Capsaicin Rhizome Curcumine Turmeric Perfumery, soaps, detergents, shampoo Seasoning, blending, natural flavours, Seasoning, blending Seasoning, blending, natural flavours, pharmaceuticals Table 2. Major plant based sources of important medicines Name of the plant Ammi majus Ananas cosmosus Active constituents Xanthotoxin Bromelain( enzyme) Atropa belladonna Atropine, Hyoscyamine, Hyoscine Barberine Papain Barberine sp. Carica papaya Camellea sinensis Cassia angustifolia C. acutifolia Cartharanthus roseus Cephaelic ipecacuanha Cichona sp. Cinnomomum camphora Colchicum Daturasp. Digitalis lantana D. purpurea Dioscoria sp. Ephedra sp. Hyoscyamus niger H. muticus Erythroxylum Glycyrrhiza glabra Physostigma venenosum Papaver somniferum Pilocarpus jabornadi Plantago ovata Podophyllum peltatum P. emodi Rauvolfia serpentina R . vomitoria Strophanthus gratis Silybum merianum Theobroma cacao Urgenia indica Valeriana officinalis Vinca minor Woacanga africana Caffeine Sennoside Vinblastin, Vincristine Ajmalicine Emetine Quinine Quinidine Camphor Colchicine Hyoscyamine, hysocine Digocine, Lantaoside-C Digitalin, Digitoxin, Gitalin Diosgenin used as raw material for sex hormones and corticosteroids Ephedrine, psuedoephedrine Hyodxuamine, hyoscine Cocaine Glycyrrhicin, glycyrrhetic acid Physostigmine Morphine, codeine, nascopine, papaverine Pilocarpine Mucilage Podophyllotoxine (Etoposide) Etoposide, teniposide Reserpine, rescinnamine, deserpidine Reserpine, ajamaline Quabain Silymarine Theobromine Scillaren A&B Valepotriates Vincamine Tuberosonine used for synthesis of vincamine Biological activity used in leucoderma Proteolytic, anti-inflammatory Anticholinergic Antibacterial Anti-inflammatory, Proteolytic CNS stimulant Laxative Anticancer Hypotensive Anti-amoebic, emetic, expectorant Anti-malarial Anti-arrhythmic Rubefacient Antigout Antispasmodic, sedative, anticholinergic Cardiotonic Cardiotonic Anti-inflammatory, hormonal, anti-fertility Bronchodilator Anti-cholinergic, anti-spasmodic Local anaesthetic Anti-inflammatory, expectorant, demulcent Cholinergic Analgesic, antitussive, smooth muscle, relaxant Parasymthomimetic Laxative Anticancer Hypotensive, tranquilliser Hypotensive, tranquilliser Cardiotonic Antihepatotoxic Diuretic Cardiotonic Tranquilliser Vasodilator Vasodilator 5 Table 3. Major plant drugs for which no synthetic substitute is currently available (Kumar et al, 1997)* Drug Ajmalacine Allicin Artemisinin Atropine Atropine Berberine Camptothecine Cardiac glycosides Catechin Cocaine Codeine Digitoxin, Digoxin Diospyrin Elipticine Emetine Forskolin Glycyrrhizin Gossypol Homoharringtonine Indicine N-oxide Magnolol Morphine Nerrifolin Nimbidin Pilocarpine Plumbagin Podophyllin Pristimerin Quassinoids Quinine Plant Catharanthus roseus Allium sativum Artemesia annua Atropa belladona Hyoscyamus niger Berberis Camptotheca acuminata Digitalis sp. Acacia catechu Erythroxylum coca Papaver somniferum Digitalis, Thevetia Diospyros montana Ochrosia Cephaelis ipecacuanha Coleus forskohlii Glycyrrhizia glabra Gossypium sp. Cephalotaxus Heliotropium indicum Magnolia bark Papaver somniferum Thevetia Azadirachta indica Pilocarpus jaborandi Plumbago indica Podophyllum emodi Celastrus paniculata Ailanthus Cinchona sp. Rescinnamine Reserpine Ricin Sophoradin Taxol Rauvolfia serpentina Rauvolfia serpentina Ricinus communis Sophora subprostrata Taxus baccata T. brevifolia Thevetia Catharanthus roseus Thevenerin, Vinblastine Use Anticancer, hypotensive Antifungal, amoebiasis Antimalarial, Spasmolytic, cold Spasmolytic, cold For leishmaniasis Anticancer For congestive heart failure Antiulcer Topical anaesthetic Anticough Cardio tonic Anticancer Amoebiasis Hypotensive, cardiotonic Antiulcer Antispermatogenic Anticancer Anticancer Peptic ulcer Pain killer Cardio tonic Antiulcer Antiglaucoma Antibacterial, antifungal Anticancer Antimalarial Antiprotozoal Antimalarial, amoebic dysentery Tranquilizer Tranquilizer Antiulcer Breast and ovary cancer, antitumour Cardio tonic Anticancer * Kumar, S., Shukla, Y. N., Lavania, U. C., Sharma, A. and Singh, A. K. 1997. Medicinal and Aromatic Plants: Prospects for India. J. Med. Arom. Pl. Sc. 19 (2):361-365. Extraction of aroma principles Several processes like hydrodistillation, steam distillation, hydrodiffusion, enfleurage, maceration, expression solvent extraction, liquid carbon-di-oxide extraction etc. are available for the extraction of aroma principles. Application of these either processes, singly or in combination, depends upon the nature of the material and of the essential oil or absolute to be recovered. Almost 50% of the cost is rendered for the extraction of essential oil from the plant material. Essential oils are obtained by distillation, usually with water or steam or as in the case of citrus fruits, by a mechanical process. Concretes are odorous concentrates obtained from fresh plant material of low resinous content by extraction with a volatile non-aqueous solvent, followed by the removal of the solvent by evaporation at moderate temperatures and under partial vacuum. Concretes are usually waxy solids. Absolutes are highly concentrated perfumery materials obtained from concretes by repeated extraction with ethyl alcohol followed by chilling of extract (to precipitate waxes and non odorous matter), filtration or centrifugation of the remaining alcohol solution and finally removal of most of the alcohol by evaporation at moderate temperatures and under partial vacuum. Absolutes are usually liquids and are entirely soluble in alcohol. Spice oleoresins are obtained from dried spices by extraction with a volatile non-aqueous solvent, followed by removal of the solvent by evaporation under partial vacuum. Oleoresins contain the aroma and flavour of the spice (including any non-volatile principles, unlike spice essential oils) in a concentrated form and are usually viscous liquids or semi-solid materials. They should be distinguished from spice aquaresins, which have closely related applications but which are extracted with aqueous alcohol rather than with volatile solvents. 6 Practically all volatile oils are complex mixtures varying widely in their composition. The characteristic odour and flavour are mainly due to oxygenated organic compounds. Only a few possess a single component in very high percentage, viz, santalol in sandalwood oil, citral in lemongrass oil, geraniol in palmarosa oil and eugenol in cinnamon leaf oil. Essential oils largely comprise the following major compounds I. Terpenoids 1. Monoterpenoids: Pinenes, ocimenes, limonene, citral, geraniol, linalool, camphor, menthol 2. Sesquiterpenoids: Caryophyllene, germacrene, cadinene, longifolene, thujopsene, aromadendrene, zizaene, cedrol, farnesol, ishwarone, santalol, cycloscychellene 3. Diterpenoids: Abietic, podocarpic and labdanolic acids; abietol, pimarinol, devadarool, ginkolide, sciarcol, manool 4. Sesterterpenoids: Geranyl farnesol, geranyl nerolidol 5. Triterpenoids: Squalene, panaxatriol, odoratol, jasminol 6. Tetraterpenoids: Carotenes, lycopene II. Benzenoids: Benzaldehyde, benzyl- alcohol, acetate, benzoate, salicylate Methyl- cinnamate, chavicol, eugenol, isoeugenol Cinnamaldehyde, cinnamyl alcohol, cinnamyl cinnamate, eugenol, isoeugenol, eugenyl acetate, isoeugenyl acetate, vanillin, anisaldehyde, anethole, asarone, elemicin, dillapiole, apiole, safrole, chavibetol III. Organic Sulphur compounds: Disulphides, sulphoxides IV. Nitrogenous compounds: gueriol pyridine, dehydroguaiol pyridine, guaipyridine, epiguaipyridine, methyl-Nmethyl anthranilate, indole, pyrazines, pyridines, Extraction of medicinal principles These medicinal principles are separated by different processes; the most common being extraction. Extraction procedures in medicinal plants are based on two major principles a) Where it is sufficient to achieve within set limits equilibrium of concentration between drug components and the solution. Eg. tinctures, decoction, teas, etc. b) Where it is necessary to extract the drug to exhaustion, ie., until all solvent extractables are removed by the solvent. Formulation and Industrial Utilisation of medicinal plants Medicinal plants are used as raw materials for extraction of active constituents in pure form (eg. alkaloids like quinine and quinidine from cinchona bark, emetine from ipecacuanha root, glycosides from Digitalis leaves, sennosides from senna leaves), as precursors for synthetic vitamins or steroids, and as preparations for herbal and indigenous medicines. Products such as ginseng, valerian and liquorice roots are part of the herbal and health food market, as well as the food flavours, fragrance and cosmetic industries. Certain plant products are industrially exploited like liquorice in confectionery, papaine as meat tenderiser, quinine as soft drink tonic and cinchona as wine flavour. A large quantity of medicinal plant material is used in the preparation of herbal and medicinal teas, eg. chamomile. Hundreds of medicinal plants are items of commerce. Several formulations like herbal teas, extracts, decoctions, infusions, tinctures, etc are prepared from medicinal plants. i. Herbal teas, Herbal remedies: Herbal tea or infusion mixtures are mixture of ungrounded or suitably ground medicinal plants to which drug plant extracts, ethereal oils or medicinal substances can be added. Infusion mixtures should be as homogenous as possible. ii. Drug extracts: They are preparations obtained by extracting drugs of a certain particle size with suitable extraction agents (menstrua). The extract obtained after separation of the liquid from the drug residue is called miscella. It may already represent the final liquid dose form eg. as a so called fluid extract, or be used as an intermediary product which is to be further processed as quickly as possible. iii. Aqueous drug extracts: The following degrees of comminution are used for the extract depending on the type of plant parts. Leaves, flowers and herbs shredded (4000mm size); woods, barks and roots shredded (2800mm); fruits and seeds (2000mm), alkaloid containing drugs powdered (700mm). iv. Decoctions: The drug in the prescribed comminution is put in to water at a temperature above 90C. The container is suspended in a water bath and maintained at this temperature for 30 minutes, with repeated stirring. The mixture is then strained while still hot. v. Infusions: One part of the comminuted drug is kneaded several times in a mortar with 3-5 parts of water and left to stand for 15 minutes. The rest of the boiling water is then poured on to the mixture, which is suspended in a container in a water bath and kept for 5 minutes, with repeated stirring at a temperature above 90C. The mixture is covered and left to stand until cool. vi. Macerates: The comminuted drug is left to stand, with occasional stirring, for 30 minutes after the required quantity of water has been poured on to it at room temperature. The extract is then strained and made up to the prescribed weight with rinsings. vii. Tinctures: Tinctures are extracts from drug plants prepared with ethanol of varying concentration, ether or mixtures of these, perhaps with certain additives, in such a way that one part of drug is extracted with more than two parts, but at most ten parts, of extraction liquid. viii. Fluid extracts: Like tinctures, they are liquid preparations, the difference being that they are more concentrated. 7 Dry extracts: They are usually very hygroscopic and should therefore be ground and mixed under conditions which exclude moisture as far as possible. Intermediate and end product must also be stored under dry conditions. There are also liquid, semisolid, solid and controlled release formulations or preparations. The other dose forms are injections, implants, ocular preparations, inhalations and transdermal systems. Liquid formulations may be solutions, emulsions, colloids or suspensions in the increasing order of particle size. They may be intended for administration parentally, orally or topically including administration into body cavities. Homogeneity of the formulations is very important, particularly where the active ingredient is present in lower concentrations. ix. Emerging opportunities The cultivation and processing of essential oil bearing and medicinal plants form an important area in the international agri-business with an estimated annual growth rate of 7-10%. India enjoys variety of climatic conditions suitable for growth of a large number of such plants. Availability of huge scientifically trained manpower, improved technologies, plant varieties, processing technologies and relatively cheaper cost of production now place India in a condition favourable for it to become a major producer, processor and supplier of aromatic and medicinal plant materials in the world market. To further augment the quality end product and maintain the acquired status, several steps will have to be taken which include up-gradation of the post harvest technologies and quality control measures, steering of the ongoing innovative R&D programmes and strengthening of the liaison with the industrial sector. In today’s world consumer boom, the essential oils and medicinal plants are exposing hitherto unexplored areas of industrial applications. Some of the emerging areas are a) Biocides Herbs and their constituents manifest varying degrees of pest controlling activities like antimicrobial, antifungal, insecticidal, ovicidal, attractant, repellent, antifeedant, antigonadal, etc. Thus, they are a potent source of environmentally and ecologically safe pesticides and could be exploited for commercialisation. Biocide preparations from herbs and extraction and production of plant growth regulators and allelochemicals are the areas where our indigenous knowledge and bio-diversity resources can be profitably exploited. The failures and non-sustainability of the chemical route to agriculture and healthcare provides an opportunity to re-evaluate our traditional knowledge systems on safe use of plant extracts for pests and disease management. The growing awareness of environment hazards from synthetic pesticides and associated problems of pest resistance and detrimental effects on non-target organisms dictate the need for safe, effective and economical pesticides. Several components of essential oils have been identified to possess short term (linalool, menthol, pulegone) and long term (benzaldehyde, carvacrol, carvone, cinnamaldehyde) fungistatic effects. Global agro-environmental concerns have necessitated search for safer and viable alternatives to the hazardous synthetic pesticides. Secondary metabolites such as essential oils are inexpensive, biodegradable, more systemic and environment friendly botanical pesticides. Use of botanicals may prove to be one of the best ways to manage food losses by pests in future. b) Allelochemicals A number of plant species produce volatile terpenes that can influence nearby growing plants. A variety of allelochemicals has been identified including volatile terpenes. The allelochemicals are considered as resources for developing herbicides and plant growth stimulants. Salvia sclaria is known to produce volatile inhibitors such as camphor, 1,8-cinole, pinene and dipentene which inhibit DNA synthesis, seed germination and growth of many weeds. Germination inhibiting activity is reported for essential oils of pepper mint, ajowan, basil and spearmint. The monoterpenoids such as carvone, linalool, methyl chavicol and anethol are most effective. c) Storage and preservation Essential oils and herbs are useful against fungal and insect infestation of various stored food commodities. Volatile oils of Pongamia glabra, Acorus calamus, Cedrus deodora, Citrus medica, Ocimum canum, O. adscendens, and O. gratissimum are potent agents against storage pests and fungal pathogens. The essential oil constituents such as citral, citronellal, citronellol, eugenol, farnesol and nerol are potential inhibitors of fungal infestation. The decay and sprouting of onion bulbs have been suppressed by oils of eucalyptus, lemon grass and camphor and also by citronellol and thymol. Essential oil has been reported to have sprout-inhibiting property on potatoes too. d) Aromatherapy Aromatherapy is an emerging art of healing using essential oils, which have therapeutic effect on body, mind and soul. The alternative and relatively less costly health care system of aromatherapy offers therapeutic effects leading to calmness, emotional balance, stress relief and rejuvenation. Essential oils have a variety of therapeutic activities including antiseptic, sedative, antiinflammatory, antispasmodic, antifungal, antiviral, stimulant, relaxant, diuretic, invigorating, euphoric and digestive. India has a long tradition of using aromatic and medicinal plants in its holistic medicinal systems - Ayurveda, Unani and Sidha. Aromatherapy was brought into practice when antiseptic and skin permeability properties of essential oils were discovered. The methods used in aromatherapy are inhalation, local application and baths, which permit the essential oils to enter the body. Once within the body, the essential oils re-establish a close harmony with the affected body parts and revitalise then. Different blends of essential oils are used for various ailments like muscular aches and pains, respiratory problems, insomnia, headache, swollen joints, urinary disorders, skin infections, palpitation, depression, indigestion, gynaecological problems, etc. Unani system of medicine employs more than 40 aromatic and medicinal plants containing essential oils as their principal constituents, such as Lavendula stoechas (ustukhudoos), Pimpinella anis (anisoon), Artemisia absenthium (afsanteen), Aqualaria agalocha (agar), Balsomodendron opobalsamum (balsam) and Anethum sowa (sowa). This can 8 easily be integrated with eco-tourism, which will help to find domestic market for indigenous essential oils thus gearing up cultivation and production sectors. e) Value addition Post harvest processing of aromatic and medicinal materials and value addition to the products of cultivated aromatic and medicinal plants are receiving attention of biochemists, phytochemists and chemical engineers who are designing effective and efficient equipment for cold and hot extraction of oils, fractions and crude extracts for domestic use and export. Possibilities on the use of micro-organisms to produce some of the value added materials bio-technologically are opening up. Indian industry also needs to perfect the use of appropriate technologies for fractionation of major and minor components of high value from the bulk produced essential oils of low sale value and transformation of low value components into high value aroma products. Encapsulated spice extractives extended on a salt dextrose carrier, encapsulated spice oils and oleoresins, homogenous free flowing oleoresins, etc are to be commercialised. With the emergence of `nature food’, `ethnic food’ and `yogic food’ and emphasis on `back to nature’ uses of spice based oils, oleoresins, ointments and flavourings would be in a bullish market in the new millennium. f) New chemicals Currently about 150 aromatic and medicinal plants and 70 spices are cultivated in different parts of the world. Out of these, probably 50 aromatic and medicinal plants and 35 spices are commonly used. But there are about 2500 Indian plant species belonging to about 60 families that are reported to have aromatic and medicinal principles. Many of these species could offer new essential oils and aroma chemicals to meet the ever changing and ever growing demand for novel natural essential oils and aroma chemicals. The potential of such lesser known aromatic and medicinal plants needs further studies and exploitation. Medicinal and aromatic plants are known as the biological mine of novel products and applications. They produce a variety of biologically active metabolites, which may confer them competitive advantage to fight against biotic stresses. Many a time, minor components in the plant material generates great demand. Hence, identification of minor chemical constituents and developing chemical profile is a felt need. Species like Saussurea costus, Nardostachys grandiflora, Pinus roxburghii, Piper nigrum, Skimmia laureola, Zanthoxylum armatum, Cedrus deodara, Cinnamomum tamala, Curcuma angustifolia, C. zedoaria, Alpinia galanga, A. calcarata and Kaempferia galanga contain essential oils in various parts. g) Eco-tourism Australia is the first country to have an eco-tourism strategy and Malaysia has followed suit. The diverse ecological zones of India offer tremendous scope for developing eco-tourism in the country. Development of ecotourism can generate substantial foreign exchange without the usual disastrous ecological degradation associated with general tourism. It will help to promote and popularize the various indigenous systems of medicine, take people closer to nature and above all promote the overall well being of the people. h) Ecotechnology The ecological foundations essential for sustained advances in biological productivity and the atmosphere are experiencing gradual degradation. There is much to learn from the past in terms of the ecological and social sustainability of technologies. Developments have opened new opportunities for developing technologies, which can lead to high productivity without any adverse effect on the natural resource base. Blending traditional and frontier technologies leads to the birth of eco-technologies with the combined strength of economics, ecology, equity, energy and employment. There is need to conserve traditional wisdom and practices which are often tending to become extinct. Eco-technologies enable adoption of ISO 9000 and ISO 14000 standards of environmental management. Conclusion Unity in diversity is our uniqueness. The rich bio-diversity of plants and diverse knowledge systems in harnessing the plant bio-diversity provide an opportunity to meet the future challenges in agriculture, health care systems, fragrance, flavors and allied areas. The failures and non-sustainability of the so-called modern approaches to agriculture and health care systems could be re-assessed through our knowledge heritage and natural resources. If information technology holds today’s fate, biotechnology will determine the future of the coming millennium. A strategic team effort in aromatic and medicinal plants research and development will pave the way for reaping the green gold for which our country is the richest repository. 9 KERALA AGRICULTURAL UNIVERSITY Aromatic & Medicinal Plants Research Station Odakkali, Asamannoor P.O., Eranakulam District, Kerala State PIN : 683 549, Tel: (0484) 658221 Dr. J. Thomas, Assoc. Professor & Head D.O. No. 943/97 Dated, 29.12.1999 Mr. Mathews, At the outset let me wish you a very happy and prosperous Millennium. Your E-mail reminded me of the commitment, which I gave you on my contribution of the article for your magazine. As I was away on Christmas vacation, I couldn’t reply your E-mail immediately. Please find enclosed the above article. As you have not informed me the length of the article, you may edit the article suitably. With warm regards, Yours sincerely, (J. THOMAS) To Mr. Vinoo Mathews, Editor Chemical Industry Digest Blockade 15, Purushottam, Ground Floor 21, JP Road (Near Navarang cinema) Andheri (W), Mumbai- 400 058
