Introduction to Pharmacognosy and Organized Vegetable Drugs (PCG 2025) PDF

Introduction to Pharmacognosy and Organized Vegetable Drugs (PCG 201) 2025-1-2  The meaning of Pharmacognosy – Pharmacognosy is derived from the Greek words pharmakon ‘a drug’ and gignosco ‘ to acquire knowledge of’ OR cognosco ‘to know about’...

Introduction to Pharmacognosy and Organized Vegetable Drugs (PCG 201) 2025-1-2  The meaning of Pharmacognosy – Pharmacognosy is derived from the Greek words pharmakon ‘a drug’ and gignosco ‘ to acquire knowledge of’ OR cognosco ‘to know about’ (Latin). The science of acquiring knowledge of drugs – Johann Adam Schmidt, an Austrian professor (1759- 1809) – It is the study of natural substances that are used in medicine or is the study of medicinal drugs derived from plants or other natural sources. Such are either plant, animal or mineral but the major origin is plant. 2025-1-2  Other definitions In pharmacognosy, we study of the physical, chemical, biochemical and biological properties of drugs, drug substances or potential drugs or drug substances of natural origin as well as the search for new drugs from natural sources. 2025-1-2  Other definitions the study of natural product molecules (typically secondary metabolites) that are useful for their medicinal, ecological or other functional properties. Other definitions are more encompassing, drawing on a broad spectrum of biological subjects, including botany, ethnobotany, marine biology, microbiology, herbal medicine, chemistry, biotechnology, phytochemistry, pharmacology, pharmaceutics, clinical pharmacy and pharmacy practice. 2025-1-2  Other definitions medical ethnobotany: the study of the traditional use of plants for medicinal purposes; ethnopharmacology: the study of the pharmacological qualities of traditional medicinal substances; the study of phytotherapy (the medicinal use of plant extracts); and phytochemistry, the study of chemicals derived from plants (including the identification of new drug candidates derived from plant sources). zoopharmacognosy, the process by which animals self-medicate, by selecting and using plants, soils, and insects to treat and prevent disease. marine pharmacognosy, the study of chemicals derived from marine organisms. 2025-1-2  Other definitions Herbal medicines inclusive of the following Medicinal Plant: A plant either growing wild or cultivated, used for its medicinal purposes. Herbs: crude material such as leaves, flowers, fruit, seeds, stems, wood, bark, roots, rhizomes or other plant parts which may be entire, fragmented or powdered. Herbal materials: either whole plants or parts of medicinal plants in the crude state. Include, herbs, fresh juices, gums, fixed oils, essential oils, resins and dry powder of herbs. Herbal preparations: the basis for finished herbal products Finished herbal products and may include communited herbal material, or extracts, tinctures and fatty oils expressed juices and processed exudates of herbal materials. Herbal medicinal products: Medicinal products containing as active substances exclusively herbal drugs or herbal drug preparations. 2025-1-2  Mode of knowledge acquisition and transmission Surrounded by mythology In some cases unknown Guarded, kept and handed down orally which is a major form of information dissemination. They write on papyrus, clay tablet, parchment, herbal manuscript, journal, pharmacopoeias, electronic devices (recently) e.g e-mail attachment, photographs. 2025-1-2  Scope of Pharmacognosy Pharmacognosy has botanical and the chemical side Botanical It is closely related to botany. There is an enormous development on the botanical side. Botany is concerned with the description and identification of drugs both in the whole state and powdered with their history, commerce, collection, preparation and storage. The botany side is fundamentally important particularly for the pharmacopoeias and quality control purposes 2025-1-2  Scope Chemical of Pharmacognosy The chemical side is concerned with isolation and identification of the chemical substances in plants. Chemical substances are isolated from plants nowadays which have afforded many of the drugs on the shelves of pharmacy e. g Vincristine and Vinblastine from the plant Catharantus roseus. Pharmacognosy should not therefore be confined to microscopy and botany but also to chromatography and other procedure necessary for the identification and determination of the purity of plant preparations. 2025-1-2  Scope of Pharmacognosy Plants have a universal role in all major areas of medicine Mesotopomia (Egypt) Western Unani (Islamic) Ayurvedic (India) Oriental (Japan) 2025-1-2  Scope of Pharmacognosy In all these systems of medicine, there is a wedge of knowledge concerning medicinal, narcotic and other properties of plants either the knowledge is recorded or orally transmitted particularly in the tropical Africa, north and south America, Pacific countries. It is in these areas that we have the greatest number of species. A complete understanding of all the plants that exist is necessary. 2025-1-2  Scope of Pharmacognosy Naturally occurring substances having a medicinal action: Surgical dressings prepared from natural fibres Flavourings and suspending agents Disintegrants Filtering and support media Other associated fields: – Poisonous and hallucinogenic plants – Raw materials for production of oral contraceptives – Allergens Herbicides and insecticides 2025-1-2  Scope of Pharmacognosy Skills & techniques valuable elsewhere: Analysis of other commodities Foods, spices, gums, perfumes, fabrics, cosmetics Used by Public analysts, forensic sciences, quality-control scientists Role in pure sciences Botany, plant taxonomy, phytochemistry Botanists and chemists looking at: Chemical plant taxonomy, genetic/enzymatic studies involving 2o metabolites Artificial and tissue culture Effects of chemicals on plant metabolites Induction of abnormal syntheses Bioassay-guided isolation techniques 2025-1-2  Scope of Pharmacognosy Cultivation and artificial propagation of species of plant whose wild forms are getting exhausted through constant exploitation Herbal medicine and homoeopathic medicine Research: despite constant exploitation, the plant kingdom still hold many species of plants of medicinal value which are yet to be discovered and large number of plants are being screened for possible pharmaceuticals like antimicrobials, antimalarials, antiparasitic, hypoglycemia to which pharmacognosy will make useful contribution. 2025-1-2  Scope of Pharmacognosy Pharmacognosy is related to: – Botany, Ethnobotany, Marine biology, Microbiology, Herbal medicine, Chemistry (phytochemistry), Pharmacology, Pharmaceutics, – Agriculture, enzymology, genetics, quality control. – It is pharmacognosy that seeks to embrace all these in a united whole for a better understanding and utilization. 2025-1-2  Classification of Drugs In any study, it is absolutely necessary to adopt some system. A haphazard random memorizing of isolated facts is of little value because the facts are not utilizable unless their relation to each other is fully understood. Therefore, in order to study drugs and medicines we must adopt some method of classification. We may adopt any of the following methods, or in fact, adopt several for different purposes : — 2025-1-2  Classification of Drugs Alphabetical: drugs are arranged like in the dictionary and pharmacopoeia. It is used if the name of the drug is known but shows no interrelationship with between drugs. Taxonomical or Botanical Classifications : they group drugs according to their family affinities, all the drugs derived from any one class of plants being enumerated together. While this system has some value in an abstract scientific sense it is of little or no practical value to the pharmacist or physician, as botanical affinities do not argue therapeutical affinities or pharmaceutical similarities. 2025-1-2  Classification of Drugs For Instance : the Rubiaceae furnishes both cinchona and ipecac ; the Leguminosae yield a heterogeneous jumble of drugs which are dissimilar in physical nature as well as in medicinal activities, as gum Arabic, Senna, catechu, balsam of tolu, logwood, Calabar bean, cassia fistula, red saunders, liquorice root, broom, tamarind and balsam of peru, representing the therapeutical groups of laxatives, astringents, cathartics, narcotics, and coloring agents, and the physical groups of gums, extracts, balsams, fruits, roots, wood, leaves and flowering tops; from the Umbellifereae we derive anise, asatotida, and conlum, etc 2025-1-2  Classification of Drugs Morphological: Here drugs are classified into groups such as leaves, seeds, flowers, fruits, herbs, entire organism, woods, barks, roots, rhizomes which are called organized drugs. Also dried lattices, extracts, gums, resins, oils, fats and waxes which are unorganized drugs. This aids the practical study of drugs and proper identification especially of powdered drugs. Pharmacological or Therapeutic: involves grouping of drugs according to the pharmacological action of the most important constituent or therapeutic use. A plant may have many constituents that may fall into different pharmacological uses. Chemical or biogenetical classification: this classifies drugs according to their chemical or biosynthetic pathways 2025-1-2  Plant Nomenclature and Taxonomy Nomenclature =name Taxonomy = classification The naming pattern usually adopted is the Binomial System of Nomenclature where 2 names are used. The first indicate Genus and begin with an upper case while the second depict species and begin with a lower case. In printing both are typed in italics but in hand writing have to be underlined. The specific name is chosen to indicate striking characteristics of the plant. 2025-1-2  Plant Nomenclature and Taxonomy Systematic plant names are strictly governed by rules which give precedence to that name used by the botanist who first described the species. Hence, each plant will adopt names (genus species underlined or italicized) and the author name e g. Azadirachta indica A. Juss; Gongronema latifolium Benth and Hook. Authors name may be abbreviated in front of the species name. 2025-1-2  Plant Nomenclature and Taxonomy Plants may be classified based on the following criteria: Phylum, Sub- phylum, Division, Class, sub-class, Order, sub-order, Family, sub-family, Tribe, Genus, Species, Variety, Races. 2025-1-2  Plant Description: Morphology and Anatomy Morphology is the scientific study of the structures and the forms of plants and animals while anatomy is the study or examination of an organization or process in order to understand how it works. Morphology is the study of the external structures of plants while anatomy is the study of internal organization of the tissue. Plant form range from unicellular plants to strongly differentiated higher plants e g. trees. Higher plants generally have 2 phases- the vegetative or growth phase and the reproductive phase. Vegetative consist of the leaves, stem, root while reproductive are flowers, fruit, seeds. 2025-1-2  It is very important that students acquire the ability to interprete the morphological and anatomical features of crude drugs as described in the pharmacopoeia and allied works and also report adequately the features of the whole powdered drugs and adulterant of commercial significance. Drugs could also be arranged based on morphological parts- leaf, stem, flower, seed. Some drugs such as whole herb, commercial root constitute more than one morphological part. Commercial stem consists of barks and stem wood. Aerial parts are the plant parts above the soil. 2025-1-2 Plant Description - Leaf and leaflets Before describing any plant we consider these 4 things: The botanical source and family The common names The geographical source The origin (whether cultivated or naturalised). In describing leaves we consider: Duration either deciduous or evergreen 2025-1-2  Leaf base with or without stipules (stipulate or exstipulate), with or without petiole (petiolate or sessile). Shape,colour, lamina(simple (palmate etc), compound (paripinate, impari-pinnate etc. Incision (entire or incised (dentate, serrate, crenate, sinuate) Apex: It could be emarginate or apiculate Base: Symmetrical, asymmetrical, cordate, Surface: green, light green Lamina: presence (pubescent) or absence of hair (glabrous); texture (coarse or brittle) 2025-1-2  Plant Description - Herbs Herbs are leaf and tops and consists of stem whose width or girth is limited by pharmacopeia requirements. Here leaves are often associated with flowers and young fruits. In describing herbs, we consider the following: Dimension, shape, colour of the aerial stem, nature of the herb either herbaceous or woody, upright or creeping, smooth or ridged. Presence and types of hairs (trichomes) The tissue arrangement of the stem as observed under the microscope. 2025-1-2  Plant Description - Herbs The position and arrangement of the leaves: either radical (leaves arising from the crown of the root e g pineapple, lemon grass, onion or cauline (from the aerial stem e g citrus, mango), there may also be adnation (fusion) of the part and the stem e.g. Solanaceae. There may be alternate arrangement of leaves e.g. Lobelia opposite (Azadirachta indica), decussate (pairs, alternate and at right angles), whorled (Pitanga). In the same plant we may have more than one arrangement. 2025-1-2  Assignments Give any 5 plants, names, including family and medicinal values 2. go into the pharmacopoeias. Look for Tobacco, senna and Ocimum and give the Macr oscopical, microscopical and diagnostic feature s 2025-1-2  BARKS DEFINITION Barks consists of all tissues outside the cambium. Bark in botany is usually restricted to the outer bark: Periderm and all the tissues lying outside it. DESCRIPTION Origin and preparation Size and shape, Outer surface, Inner surface, Fracture, Transverse surface 2025-1-2  BARKS Brief anatomy: A young bark consists of (i) Epidermis (ii) 10 cortex (iii) endodermis (iv) pericycle (v) Phloem Powder elements: sieve tubes, cellulose parenchyma, cork, fibres, sclereids, Calcium oxalate secretory tissues, Xylem tissues absent or present only in small amounts, no chlorophyll or aleurone grains. 2025-1-2  Woods DEFINITION Consists of the secondary tissues produced by the cambium on its inner surface. DESCRIPTION Size and colour, relative density, hardness and behaviour when split, transverse surface, Longitudinal surfaces 2025-1-2  Leaves or Leaflets DEFINITION Description: Duration, Leaf base, Petiole, Lamina, Surface, colour, Texture. Brief Anatomy: Epidermis, mesophyl consisting of parenchyma, collenchyma or sclerenchyma, vascular system, Palisade, Powder: epidermis with stomata, cellulose parenchyma, not very abundant small sized vascular elements, and chlorophyll, epidermal trichomes, glands, palisade cell, crystal of calcium oxalate collenchyma and pericyclic fibres. Quqntitaive microscopy. 2025-1-2  Subterranean organs(root and stem) These structures are often modified into underground stem called rhizomes or runners with a stem structure which are called stolons. Stipules, bracts are reduced and modified leaves while tendrils are modified stems. Climatic conditions may cause reduction or total absence of some organs e.g. in some xerophytes we have reduction of leaves into thorns or spines e.g. Cactus plants. 2025-1-2  Definition: consists of (i) stem structures such as corms, bulbs, stem tubers and rhizomes and (ii) root structures such as true and adventitious roots and root tubers. Description: Morphological nature, condition, sub aerial stem. Subterranean stems: size, shape, direction of growth and branching, surface characters, fracture and texture, transverse section. Roots: Kind, size, shape, surface characters, , fracture and texture, transverse section Monocotyledonous rhizome: scattered arrangement of vascular bundles in contrast to dicot which is well arranged. Stem bear buds and well marked piths. Underground organs: no chlorophyll, abundant starch when present and in long grain reserve 2025-1-2  Inflorescences and flowers Definition: are the reproductive parts of a plant Description: Type of inflorescence, axis or receptacle of inflorescence, type of flower, receptacle of flower, calyx, corolla, androecium, Gynaeciaum, ovules. Brief anatomy: flower stalk with stem structure, bracts, calyx, corolla with a leaf structure and a striated, cuticularised epidermis, coloured fragments, stigma with papillose epidermis, fragments of anther Powder: pollen grains, fibrous layer of anther wall, papillose epidermis of stigma. 2025-1-2  FRUITS Definition: 3 types in Pharmacognosy: simple(one pistil; dry indehiscent, dry dehiscent ), aggregate(> one pistil e. g. aconite), collective(from an inflorescence e. g. fig) Description: Shape and dimension, Adhesion, dehiscence, pericarp, placentation, seeds, other characters 2025-1-2  FRUITS Brief anatomy: pericarp bound by inner and outer epidermis, outer epidermis bear hairs and stomata. Fleshy: parenchymatous internal tissue; Dry: fibres and sclereids, secretory tissues like oil ducts, latex tissues, vittae, pitted fibres, spiral vessels abundant empty spiral vessels 2025-1-2  Seeds Definition: Consists of a kernel surrounded by one, two or three seed coats. Most seed have 2 seed coats, outer testa and inner tegmen Are produced from ovules of the flowers Be careful to be able to distinguish seeds from fruits or parts of fruits containing a single seed. Description: size, shape & colour, funicle, hilum and micropyle, seed coats, perisperm, endosperm, embryo 2025-1-2  Seeds Brief anatomy: sclerenchymatous layer, epidermis of testa highly characteristic and thick-walled, may bear characteristic hairs; storage tissues: contain starch, aleurone, calcium oxalate, fixed oil, volatile oil. Fruits and seed similar in anatomy but has greater vascular tissues and lignified elements 2025-1-2 2025-1-2  The typical characteristics that define the plant cell include cellulose, hemicellulose and pectin, plastids which play a major role in photosynthe sis and storage of starch, large vacuoles respons ible for regulating the cell turgor pressure. 2025-1-2  They also have a very unique cell division proc ess whereby there is the formation of a phragm oplast (a complex made up of microtubules, mi crofilaments, and the endoplasmic reticulum) a ll assembling during cytokinesis, to separate th e daughter cells. These organelles most of them are similar to the animal organelles performing the same functions as those of the animal cell. Organelles have a wide range of responsibilities that include everything from producing hormones and enzymes to providing energy for a plant cell. 2025-1-2  Plants cells have DNA that helps in making ne w cells, hence enhancing the growth of the plant. the DNA is enclosed within the nucleus, an envel oped membrane structure at the center of the cell. The plant cell also has several cell organelle stru ctures performing a variety of functions to maint ain cellular metabolisms, growth, and developme nt. 2025-1-2  Cell differentiation The plant cell is composed of organelles like Golgi apparatus- secretory bodies which operate in cell wall formation. Their vesicles split off and transport materials across the plasmalemma (outer membrane of the protoplast) into the cell wall. Lysosomes: membrane –bound organelle which are involved in pinocytosis and contains hydrolytic enzymes. They are of variable origin either Golgi vesicles or from enclosure of mitochondrion by portion of the smooth ER, they break away from the main structure. 2025-1-2  are the power houses of the cell which with chloroplast make available the energy for plant and animal life. Enzymes of TCA are situated in the outer wall while the sequence of reactions that gives rise to ATP occurs in the inner membrane. Chloroplast: auto reproductive green plastids restricted to the green plant cell, the complete photosynthetic unit which utilizes light energy of the sun to reduce CO2 to carbohydrate in the presence of water. Other coloured plastids like chromoplast are derived from chloroplast. 2025-1-2 containing various ergastic materials such as calcium oxalate, silica, mineral salts, reserve proteins, starch, hesperidin and most of the secondary metabolites of pharmacognostical significance. All these occur either in solution or in the vacuolar sap or as deposits. The origin is uncertain and may include coalescence of some vacuoles derived from the Golgi apparatus, ER or growth of some hydrophilic macromolecules 2025-1-2  Cell Modification The above cell structures may be modified. These modifications involve the composition of the cell wall, cell shape, and cell contents and are found in various tissues and furnish those microscopical characters which are of value in the identification and detection of adulteration of crude drugs. Cell wall: The original cell wall may undergo various chemical modification during differentiation which may profoundly change its physical properties. Such as deposition of further cellulose or hemicelluloses, incrustation of the wall by lignin, cutin, or suberin. Algae wall which commonly contain pectin mixed with cellulose, xylose, mannose or silica may also contain hemicelluloses, alginic acid, focoidin, fucin, geloses and chitin. Cellulose cell wall: the proportion of cellulose , pectin and hemicellulose present dictates the reaction of such walls to reagents. 2025-1-2 reagent reaction remarks Chlor-Zinc- Iodine, blue cellulose iodine, then concentrated acids yellow Pectic substances Blue, violet,, brownish violet Various proportions of or brown cellulose and pectic substances Iodine No colour True cellulose Blue colour hemicellulose Ammoniacal solution of Dissolves true cellulose Soluble : cellulose Copper Oxide BPC but precipitates cellulose once Insoluble: hemicellulose alkaline liquid is poured into dilute sulphuric acid Phloroglucinol+ hydrochloric No pink or red colour cellulose acid 2025-1-2  Lignified walls: Lignified walls: Lignin is a strengthening material which impregnates the cell wall of tracheids, vessels, fibres and sclereids of vascular plants. The lignin content of wood is about 22-34%. It differs according to the source whether dicot or conifers. In the cell wall it appears combined with hemicellulose and is highly concentrated in the middle lamella and the primary wall. 2025-1-2  Lignified walls: reagent reaction remarks Acid aniline sulphate Bright yellow lignin Phloroglucinol + Pink or red Lignin, pentose sugar hydrochloric acid Chlor-Zinc- Iodine yellow Lignified wall 2025-1-2  Suberised and cutinised walls Suberin and cutin consists of mixture of substances chiefly highly polymerized fatty acids such as suberic acid. However the acids of either are not identical. These material waterproof the cell in which they occur. Suberin thickenings that are found in cock cells and endodermal cells, usually consists of carbohydrate –free suberin lamellae. Cutin: forms secondary deposits on or in a cellulose wall. Found covering leaves and may show as characteristic papillae, ridges and striations. The cellulose walls may be impregnated with cutin beneath the cuticle such that there may be a gradation of pure cellulose from inside to outer cuticle which may be cellulose free. Waxes may occur with suberin and cutin. 2025-1-2  reagent reaction remarks Chlor-Zinc- Iodine Yellow- brown colour Suberin/ cutin Suberised and Sudan glycerin red cutinizedSuberin/ walls cutin Strong solution of potash yellow Suberin/ cutin (cutin more resistant) Dilute tincture of alkanna red Suberin/ cutin Conc. Sulphuric acid Does not dissolve Suberin/ cutin Conc. Chromic acid Little effect Suberin/ cutin Pot. Chlorate, Nitric acid Walls change to droplets Suberin/ cutin soluble in organic solvents ore dilute potash. 2025-1-2  Mucilaginous walls Certain cell walls may be converted into gums and mucilages by a process called gummosis which may be observed in the testa of many seeds (Linseed and mustard), outer layers of some aquatic plants and in the stems of some species of plants (Prunus, Citrus and Astragalus) 2025-1-2  Chitin forms the major part of the walls of It belongs to crustaceans, the family insects Moraceae and many fungi. It gives no reaction is commonlyfor cellulose calledor lignin. Chitin is figs converted to chitosan, ammonia and It is a large genus of about 1400 species. acetic or and oxalic acid when heated for I hr with 50% It includes trees0 and shrubs of very varied potash at 160-170 C. Chitosan give a violet habit. colour when treated first with 0.5% Iodine in It is mainly Potassium tropical or subtropical Iodide and then with1% sulphuricand contains latex. acid. Chitin can be obtained from shrimp scales, This genus elytra is host of beetles to lac producing or defatted ergot insects, 2025-1-2  Differentiated tissues of medicinal plants Some tissues that are characteristic of medicinal plants and so are useful in their identification. (i)Parenchyma tissue Parenchyma cells occurring in various parts of the plant is potentially meristematic, they achieve maturity without further differentiation except for increase in cell size, wall thickness and a restricted change in form. They are primarily isodiametric and possess a protoplast capable of division and a cell wall composed of cellulose. Parenchyma cells are components of the pith, cortex , rays of plant axis and mesophyll of leaves. Parenchyma cells of mesophyll of leaves may be differentiated into palisade and spongy mesophyll. 2025-1-2  a living tissue directly derived from parenchyma but having greater mechanical strength. The wall are thickened, the thickening being composed of cellulose laid down in longitudinal strips commonly located at the angles of the cells. The cells are usually 4 or 6-sided in transverse section, axially elongated when seen in longitudinal section. The presence of cellulose in collenchyma made it to have considerable plasticity and hence it constitutes the typical mechanical tissue of herbaceous stems and of petioles and midrib of leaves. Collenchyma is present above and below the midrib bundle in many leaves e.g. Senna, Stramonium, Hyoscamus, Belladonna, Digitalis, Lobelia, in the cortex of Cascara bark and the pericarp of Colocynth and Capsicum. 2025-1-2  (ii) Epidermis The epidermis consists of a single layer of cells covering the whole plant. They show a variety of form giving characteristic pattern when seen in surface view. Stomata guard cells are differentiated epidermis which contain chloroplast. The epidermis of the root constitute the piliferous layer. In transverse section, epidermal cell are flattened, parallel to the surface and square or rectangular in shape while the outer walls are often convex and most markedly thickened. 2025-1-2  of first importance in the identification of leaves where they may be straight-walled (Jaborandi, Coca, senna); wavy-walled (Stramonium, Hyoscamus, Belladonna); beaded-walled (Lobelia inflata, Digitalis lanata); papillose (coca leaf). The epidermis may also be CUTICULARISED, covered with cuticle which may be thick (Aloe and Bear berry), striated (Belladonna, Jaborandi, Digitalis lutea, Digitalis thapsi); 2025-1-2  Other inclusions in the epidermis The epidermis may also possess mucilage (senna, buchu leaves). Chrysolith of Calcium carbonate (Urticaceae, Cannabinaceae) and spheocrystals of diosin can also be found in the epidermis of buchu. In describing the epidermis, consider (i) the shape in surface and in section (ii) nature and distribution of wall thickenings (iii) presence or absence of cuticle, its form and distribution (iv) structure of the stomata, presence or absence of well- differentiated subsidiary cell of the stomata (v) The presence of characteristic cell inclusions such as crystoliths, (vi) Presence or absence of and form, size and distribution of epidermal trichomes (vii) Presence or absence of and form, size and distribution of water pores 2025-1-2  of one kind or the other. Many show one or more type: glandular or non- glandular: unicellular may vary from small papillose outgrowth to large robust structures, multicellular hairs: may be uni, bi or multi- serriate or complicated branched structure. may have unicellular or multi-serriate stalk. The cuticle of the gland may be raised by secretion. Also a particular type of hair may characterise a family e. g. biserriate hairs are common in Compositae while glandular hairs are found in Solanaceae and Labiatae 2025-1-2  (iv) Endodermis (also called Internal epidermis) It is a specialized layer of cells marking the inner limit of the cortex. A typical endodermis can be found in roots, aquatic and subterranean stems and in aerial stems of certain families e.g. Labiatae and Curcurbitaceae. Leaves and aerial stems show a starch sheath probably representing a modified endodermis. The cells of the endodermis appear in transverse section as 4-sided, oval, elliptical and often extended in the tangential direction. The cells are longitudinally elongated with the end walls often transverse. It may be primary or secondary. Secondary wall when there is deposition of specially modified materials resembling cutin, followed by suberin lamellae being laid down with the primary wall giving a secondary endodermis. This may be followed by the deposition of a secondary wall of lignocellulose giving a tertiary endodermis as in Aletris and Smilax. The structure of the endodermis may be diagnostic of the commercial species of Smilax 2025-1-2  (v) Cork tissues As the plant axis increases in diameter, the epidermis is replaced by cork tissues while the stomata replaced by lenticels which are special breathing apparatus larger in size and smaller in number than stomata. The simplest form of lenticels consists of a mass of unsuberised thin-walled cells. Cork tissues are formed by the activity of the cork cambium or phellogen as a result of which new protective tissues known collectively as Periderm are formed which replace the epidermis and part or all of the primary cortex. Cork cambium undergoes tangential division to give rise to the Phellem (cork tissues) externally and phelloderm, or secondary cortex internally. Production of phelloderm is usually smaller than Phellem. In the root, the cork cambium arise in the pericycle. In stem, it arises in the epidermis or in the sub epidermal layer or deep seated cork cambium may be persistent or have limited period of activity. The cork tissue is built up of a compact cells usually rectangular in transverse section, 5 or 6-sided in surface view and often arranged in regular radial rows. The cell wall is composed of inner and outer cellulose layers and a median suberin lamella laid down upon the cellulose cell wall. The cellulose layer may be lignified as in Cassia. The mature cork cells is dead, impermeable to water and often filled with dark reddish brown contents rich in tannins and related substances. Its presence in powdered drugs may show adulteration or the use of low quality improper peeled drug. 2025-1-2  Sclereids: also called stone cells, they are sclerenchymatous cells approximately isodiametric in shape. The walls of a typical sclereids are thick, lignified after showing well- marked stratification and transversely by pit canals which are often funnel- shaped or branched. The central lumen is usually small sometimes completely obliterated. Cell contents of diagnostic significance may be present e.g. prism of 2025-1-2  Micrometry It is the technique of the measurement of an object on the microscope. It is very useful in the examination of food drugs and it may aid the differentiation of an authentic drug from an adulterant 2025-1-2  DEFINITION OF A LEAF The leaf is an important part of the plant, an appendage to the stem. It is the expanded structure which takes part in photosynthesis. It consists of the blade or lamina and the petiole and exhibit a variety of external features. 2025-1-2  » LEAF MACROSCOPY OF LEAF 2025-1-2  DEFINITION OF A LEAF contd It can be recognized by four well-marked characters namely their flattened form, their thinness, the presence of chlorophyll and the presence of supporting and conducting strands called veins 2025-1-2  DESCRIPTION OF LEAF DRUGS 1. Names- common names, local names and botanical source. 2. Macroscopical features-physical appearances, description to incorporate colour, taste before and after drying. 3. Microscopical features, may include detailed anatomy, arrangement of the cells and tissues or diagnostic characteristics of the powder. 2025-1-2  OTHER MEANS OF DESCRIPTION some other quantitative parameters as Stomatal index, palisade ratio, stomata number, vein islet number, Veinlet termination numbers. 4. Chemical tests for chemical constituents 5. Uses including medicinal uses 2025-1-2  MACROSCOPY OF LEAVES Composition (Incision: simple or compound) Shape (linear, lanceolate, elliptical, ovate, obovate, oval, round, spathulate, rhomboidal, cuneate) Apex(acute, obtuse, acuminate, mucronate, apiculate, emarginate, truncate, recurved) Sizes (length X breadth) Margin (entire, dentate, serrate, crenate, sinuate) 2 different types of margin may be observed in a single leaf 2025-1-2  Leaf shapes and apex 2025-1-2  Margin and leaf bases 2025-1-2  MACROSCOPY CONTD Base: sessile/ petiolate (equal, unequal, amplexicus,tapering, cordate, decurrent) Surface (adaxial, abaxial, pubescent, glabrous, presence of special features like oil ducts) Venation (parallel or reticulate) Midrib (prominent or depressed) Number of lateral lines and the angles at which they leave the midrib or whether they run straight to the margin or divide or anastomosing 2025-1-2  MACROSCOPY OF LEAVES 2025-1-2  Anatomy of the leaf The anatomy of the leaf reveal a basic structural pattern that yield character which enable the presence of leaf to be detected in a powder. There are however some less general characters that will make the distinction between monocot and dicot leaves to be made and also xerophytes and helophytic leaves.The more detailed anatomic characters will when taken together allow identification of the genus and species of a leaf 2025-1-2  Anatomy contd 3 distinct tissues layers can be discerned in the transverse section through most leaf drugs. (1).The epidermis with its cuticle and stomata, the epidermis is protective. (2).The mesophyll is where most of the chloroplast are found and photosynthesis takes place ,the mesophyll is parenchymatous. it is divided into palisade and spongy mesophyll. 2025-1-2 2025-1-2  (3).The leaf vein which transport water and inorganic compounds produced by photosynthesis away from the leaf, to other parts of the plant 2025-1-2  The epidermis The epidermis with its cuticle and stomata, the epidermis is protective. 2025-1-2  The mesophyll The palisade mesophyll consist of one or several layers of elongated, narrow parenchyma cells with their long axis at right angles to the axis of the leaf and are situated under the adaxial (upper) epidermis. Chloroplast are concentrated in the palisade mesophyll and much of the photosynthesis takes place here. 2025-1-2  The mesophyll contd The spongy mesophyll consists of irregularly shaped parenchyma cells which are located below the palisade mesophyll cells. Many intercellular spaces between spongy mesophyll cells which are inter connected communicate with the abaxial epidermis. This allows the food producing cells of the leaf the (mesophyll) to access the gases CO2 and O2) which they need for photosynthesis and respiration. Op 2025-1-2  The leaf veins Veins are also called the vascular bundles transport water and dissolved mineral salt into the leaf which are used for the production of organic substances during photosynthesis and related pathways which takes place in the leaf. tissue substances away from the leaves to other part of the plants 2025-1-2  The leaf veins contd 2 types The larger veins have xylem with vessels and tracheids and phloem with sieve tubes and companion cells. Here, the xylem is orientated towards the adaxial (upper) epidermis. The veins are surrounded by parenchyma cells through which water and dissolved organic and inorganic substances must pass when entering or leaving the vein. The bundle sheath may or may not contain chloroplast Smaller veins may consist of the xylem only 2025-1-2  Investigating the structure of the leaf examine the transverse section through the lamina, midrib and portion of the whole leaf including leaf margin cleared in chloral hydrate stain for cellulose and lignin and apply microchemical tests for mucilages, tannins, volatile oils, calcium oxalate and carbonates. Obtain a surface preparation of both epidermis 2025-1-2  Epidermis The shape, size and wall structure of the epidermis, the form, distribution of the stomata, and relation to the epidermal cells the form, distribution and abundance of the epidermal trichomes are all of diagnostic importance 2025-1-2  Mesophyll Mesophyll may be differentiated or not differentiated into spongy and palisade tissue Palisade tissue may be present below both surfaces (isobilateral) or only below the upper epidermis (dorsiventral) Mesophyll, though typically parenchymatous may contain groups of collenchyma or sclerenchyma, secretion ducts or latex tissues, oil or mucilage cells, hydathodes (water pores) Cells may contain inclusions such as crystals of calcium oxalate, the size or distribution of which may have importance. 2025-1-2  The leaf veins The structure of individual vein is subject to a considerable variation. The midrib bundle may be poorly or markedly differentiated, the palisade is usually interrupted in the midrib region and collenchyma usually occur above and below the bundle The main vein in dicot leaves are open and usually collateral and less commonly bicollateral. The xylem faces towards 'the upper epidermis 2025-1-2 2025-1-2  The leaf veins contd Various degrees of secondary thickening of the midrib are seen in the leaf The lateral veins are almost entirely collateral even in cases where the midrib is bicollateral. The smallest veins often consist of the xylem only Veins of monocot leaves are closed bundles 2025-1-2  POWDERED LEAVES epidermis with stomata cellulose parenchyma cells not very abundant small-sized vascular elements. Chlorophyll except in bulbs Structures frequently present are epidermal trichomes, glands, palisade cells, crystals of calcium oxalate, collenchyma and parenchyma fibres 2025-1-2  QUANTITATIVE MICROSCOPY PALISADE RATIO: this is the average number of palisade cells beneath each epidermal cell. It is determined by tracing out the palisade cells under a group of four epidermal cells, counting them and getting the average. This could be diagnostic for species of plants or even varieties. STOMATAL NUMBER. This isold the average number of stomata per square millimeter of epidermis. It is counted for each surface anand the average determined. The ratio for upper and lower surfaces may be useful. 2025-1-2  STOMATAL INDEX: It is the percentage proportion of the ultimate divisions of the epidermis of a leaf which has been converted to stomatal I=S/E+S*100 S is the number of stomata per unit area, E is the number of ordinary epidermal cells 2025-1-2  Stomatal number varies with the age of the leaf but stomatal index is highly constant for a given species and can be determined on entire or powdered samples. It can be used to distinguish between Indian and Alexandrian senna 2025-1-2  VEINLET TERMINATION NUMBER: The number of veinlet termination per mllimetre square of leaf surface. A veinlet termination is the ultimate free termination of a veinlet or branch of a veinlet. This character can be used to distinguish between leaves e. g. Peruvian and Bolivian coca leaves 2025-1-2  VEIN ISLET NUMBER: a vein islet is the minute area of photosynthetic tissue encircled by the ultimate divisions of the conducting strands. The number of vein islet per square millimeter is calculated from four contiguous square millimetres in the central part of the lamina midway between the midrib and the margin. 2025-1-2 Leaf drugs to be considered in this course Ficus Groups A and E Digitalis Groups B and D Catharanthus Groups A and E Thevetia Groups B and C Ocimum Groups A and D Azadirachta Groups A and C Tobacco Groups D and C Senna Groups B and E 2025-1-2  FICUS It belongs to the family Moraceae is commonly called figs It is a large genus of about 1400 species. It includes trees and shrubs of very varied habit. It is mainly tropical or subtropical and contains latex. This genus is host to lac producing insects, 2025-1-2  FICUS contd Examples of the species are F. benghalensis (banyan), F. carica (common fig), F. elastica (Indian rubber tree), F. voegelli (West African rubber tree) F. religiosa, F. salicifolia F. racemosa , F. glomeratus. 2025-1-2  Ficus is a genus of about 850 species of woody trees, shrubs, vines, epiphytes and hemiepiphyt es in the family Moraceae. Collectively known as fig trees or figs, they are native throughout th e tropics with a few species extending into the s emi-warm temperate zone. 2025-1-2  http://www.westafricanplants.senckenberg.de/r oot/index.php?page_id=14&id=3121# http://www.westafricanplants.senckenberg.de/r oot/index.php?page_id=14&id=3121# 2025-1-2  Ficus exasperata 2025-1-2  Ficus exasperata 2025-1-2  MACROSCOPY of Ficus voegelli It is the leaves of Ficus voegelli The tree is about 20-60 ft and grows in the rain forest of Mozambique along with other plants. The leaves are 9-18 cm long and 4-5 -9 cm broad. Leaves are elliptical or oblong elliptical, obtuse to rounded or sub-truncate at base. The main lateral veins of the leaves are about 8- 12 cm on each side of the midrib more or less parallel with intermediate secondary nerves slightly prominent beneath. 2025-1-2  MACROSCOPY contd They are coriaceous and sometimes acutely acuminate, glabrous about 6mm in diameter and beaked when dry. It is commonly called ‘Oba Odan’ the stomata of the leaves is confined to the lower surface of the epidermis 2025-1-2  CHEMICAL CONSTITUENTS Flavones and benzoquinnolines. 2025-1-2  Uses of some other species F. religiosa: Treat constipation (leaves), Purgative (leaves and young shoot) F. racemosa: Astringent to bowels, Bronchitis. The latex is often anthelmintic because of the proteolytic enzyme Ficin 2025-1-2  DIGITALIS also called Purple foxgloves consists of the dried leaves of Digitalis purpurea Family Scrophulariaceae. Origin: A biennial or perennial herb formed readily from seeds (common in England and the continent, except in the Mediterranean region, naturalized in North America and produced commercially in Holland. In the first year, it forms rosettes of leaves and in the second year an aerial stem(1- 1.5m in height 2025-1-2  DIGITALIS Habitat: Wild semi shady position, cultivated, sandy soil rich in a certain amount of Manganese Preparation: Leaves should be dried rapidly at a temp of about 600C after collection and subsequently stored in air tight containers and moisture content should not be more than 6%) 2025-1-2  Digitalis purpurea 2025-1-2 2025-1-2  MACROSCOPY Shape: Ovate – lanceolate or broadly ovate,10-30cm long and 4-10cm wide dried leaves are of dark to grayish green colour, lamina decurrent at the base and most of the teeth show large water pore. Both surfaces hairy particularly the lower, a fringe of hair is found on the margin Veins depressed on the upper surface but prominent on the lower surface. Main veins leave the midrib at acute angles afterwards branching and anastomosing repeatedly No marked odour but a bitter taste 2025-1-2  MACROSCOPY 2025-1-2 2025-1-2  MICROSCOPICAL CHARACTERS Typical bifacial structure Midrib strongly convex on the lower surface Stomata and hair present on both surfaces but more numerous on the lower surface Calcium oxalate is absent Palisade tissue is interrupted at the midrib 2025-1-2  MICROSCOPICAL CHARACTERS A zone of collenchyma underlies both epidermis in the midrib region Midrib bundle is crescent-shaped and enclosed in an endodermis which is one or two cells thick developed as a starch sheath Pericycle parenchymatous above a collenchymaous below Sclerenchyma fibres are absent 2025-1-2 CHEMICAL CONSTIUTUENTS The primary constituents are called tetraglycosides. 1. Purpurea glycosides A. 2. Purpurea` glycosides B 3. Glucogitaloxin. 2025-1-2  Digitoxigenin 2025-1-2  Gitaloxigenin 2025-1-2  Gitoxigenin 2025-1-2 CHEMICAL CONSTIUTUENTS They are called tetraglycosides because there are attached to the genin at the C-3 position 4 sugar units- 3 digitoxose and a terminal glucose each Purpurea glycosides A= digitoxin +terminal glucose Purpurea` glycosides B= Gitoxin+terminal glucose Glucogitaloxin=gitaloxin+terminal glucose 2025-1-2 CHEMICAL CONSTIUTUENTS Digitoxin=digitoxigenin+3 digitoxose units Gitoxin= gitoxigenin+3 digitoxose units Gitaloxin= gitaloxigenin + 3 digitoxose units Other glycosides present are verodoxin which have digitalose and glucose as the glucose unit but same aglycone with digoxin and gitoxin Anthraquinone derivatives, Saponins and a number of leaf flavonoids 2025-1-2  ALLIED DRUGS: Digitalis thapsi. D. lutea D. ferruginea ADULTERANTS: Verbascum thapsus, Synphytum officinale (comfery), Primula vulgaris (primrose), Inula helenium (elecampane), Inula conyza (ploughman spikenard), Utica dioica (nettle). 2025-1-2  Uses of Digitalis Digitalis is a medicine that is used to treat cert ain heart conditions. It is used in the treatment of dropsy (to produce improvement on the faili ng heart) Digitalis toxicity can be a side effect of digitalis therapy. It may occur when you take too much of the drug at one time. It can also occur when levels of the drug build up due other medical problems 2025-1-2  CATHARANTHUS Catharanthus roseus Also called Madagascar periwinkle, Vinca roseus and Lochnerea rosea. It belongs to the family Apocynaceae. indigenous to Madagascar but is now widely distributed throughout the warm regions much cultivated as ornamental, 2025-1-2  ORIGIN grows profusely in southern Florida. Commercial supplies are obtained both from cultivated and wild variety produced in various locations including Africa, India, Thailand, Taiwan, Eastern Europe, USA and Australia herbaceous sub-shrub, 40-80 cm high becoming woody at the base. 2025-1-2  MACROSCOPY The leaves are oppositely arranged oblong and elliptic with dimension 2-7cm and 1.5-3.0 cm with a petiolated acute base, a rounded mucronate apex and an entire margin. has glabrous , entire shiny edges, it is greenish –greyish after dessication has a feeble bitter taste glabrous epidermis with some fibres, turns slightly green with iodine peripheral parts is ligneous with an island of riddled perimedullary tissue 2025-1-2  Catharanthus roseus leaf 2025-1-2  CONSTITUENTS About 150 alkaloids have been isolated: vincristine, vinblastine, ajmalicine, lochnerine, serpentine, trahydroalstonine,. Leaf contains 5-10% water and 8% mineral matter. it also contains several organic acids such as protocatechuic acid, caffeic, p-hydroxy benzoic acid and carbolic acid(3.7%) of the dried drug. Also found is a volaltile monoterpene,tanniosd, flavone pigments and chiline. Active principles of the drug are the indole alkaloids representing 0.4-0.9% depending on the geographical origin of the dried leaves. vincenine, vincamine 2025-1-2  Vinblastine 2025-1-2  Vincristine 2025-1-2  USES Anticancer, Antidiabetic?? It is used in traditional medicine as anti diabetic. Its alkaloids are used as antitumor drugs. Vincristine is administered as sulphate or injection in haemopaths and lymphoblastic leukaemia. Vincaleukoblastine (Vinblastine) is used in hodgkins disease- a common cancerous disorder in which there is proliferation and multiplication of the cells of the lymphoid tissue (found in the lymph nodes and spleen and liver 2025-1-2  OTHER SPECIES C. longifolius, C. trichophyllus and C.lanceus 2025-1-2  THEVETIA Thevetia nerifolia is a small tree usually 6m high and bearing white latex. It is commonly called yellow oleander, thefetiah (Arabic), Olomiojo (Yoruba). usually cultivated as an ornamental plant. The leaves are alternate,quasi linear - lanceolate 2025-1-2  Thevetia nerifolia 2025-1-2  CHEMICAL CONSTITUENTS The plant contains thevetin A, thevetin B, nerifolin, fixed oil and protein. an iridoid heteroside,aucubin have also been isolated from the leaves and fruit of the plant. The kernel yields a coloured oils. 2025-1-2  Thevetin A 2025-1-2  Thevetin B 2025-1-2  Neriifolin 2025-1-2  MEDICINAL USES It is considered to be extremely poisonous and is very rarely used as an ingredient in the preparation of remedies. A weak decoction of the stem bark is used for treating intermittent fevers Thevetin, peruvoside and nerifolin are short acting cardiotonic. The glycosides are rapidly eliminated and not considered very important in clinical medicine as there is little difference between effective and toxic doses 2025-1-2  OCIMUM Ocimum gratissimum is a leaf drug belonging to the family Labiatae. It is commonly called tea bush, mosquito plant, and fever plant of Sierra Leone. In Yoruba , it is called Effirin. It is commonly found in gardens , compounds, old farm near villages and is often cultivated in various parts of West Africa. It is the fresh young leaves of Ocimum gratissimum containing not more than 2% of the stem. It has a thyme- like pungent characteristic odour. The taste is pungent and aromatic 2025-1-2  MACROSCOPY Leaves are about 6-12 cm long and 3cm broad. They vary from ovate to obovate in shape with cuneate base while beneath it is sub- glabrous but gland pitted and slightly pubescent on the nerves. The petioles are rather long 2025-1-2  MICROSCOPY The midrib and the transverse section of O. gratissimum leaf shows a bifacial structure and characteristic sub-epidermal masses of collenchyma cells on both surfaces. The xylem takes the form of strongly curved arc. It posses diacytic stomata on both surfaces though more common on the lower epidermis Hairs numerous in young leaves particularly in the midrib and veins. Hairs are uniserriate and 3-8 cells long, slightly curved with thin warty walls 2025-1-2  QUANTITATIVE MICROSCOPY Palisade ratio: 4.25-5.89-7.5 Stomatal Index (U): 12.5-28.7; (L) 18.2-28.5 Stomatal Number: 100-184-300 Vein Islet Number: 300-317-400 Veinlet Termination Number: 10.0-14.5 2025-1-2  CHEMICAL CONSTITUENTS, USES & STORAGE Volatile Oil (3%v/w), Thymol and or eugenol- (up to 75% of the entire oil) and other terpenes Antibacterial, spice, anti diarrhoeal Store in an air tight container in a cool place protected from light. Use leaves fresh 2025-1-2  Azadirachta indica A.Juss It is the dry leaf of Azadirachta indica which belongs to the family Meliaceae, It is a leaf drug with strong characteristic odour and bitter taste. It is popularly called neem or dongoyaro. It originated in India but is naturalized all over the inter tropical Africa especially in the coastal plains 2025-1-2  Azadirachta indica A. Juss 2025-1-2  MACROSCOPICAL The leaves are pinnate and alternated in arrangement on each side of the leaf. There may be 5- 8 pairs of leaflets attached to the main strand through a small petiole. The leaflets are ovate – lanceolate, fulcate and asymmetrical at the base. acuminate and coarsely serrated at the edges with acuminate apex and glossy appearance. 2025-1-2  MICROSCOPICAL FEATURES. Transverse section of A. indica leaves show a collateral structure and characteristic sub- epidermal masses of collenchyma on both surfaces. The xylem takes the form of strongly curved arc while both surfaces have smooth cuticle, epidermal cells with almost straight walls particularly those of the upper epidermis. The stomata is anomocytic in the lower epidermis only ,no stomata in the upper epidermis. 2025-1-2  CHEMICAL CONSTITUENTS Azadirachtin, solanin, meliantrol, azadirone, azadiradione and other meliacins DIAGNOSTIC CHARACTER indica has no starch granules in its powder, no calcium oxalate crystals or rosettes 2025-1-2  QUANTITATIVE MICROSCOPY Palisade ratio 4.5-6.2-7.8 Stomatal Index (U); 5 -12.8; (L) 18.2-28.5 Stomatal Number: 200-333-500 Vein Islet Number; 2.5-3.0 Veinlet Termination Number:26.0-28.0 2025-1-2  USES Fresh leaf-tea is used for malarial and anti inflammatory agent. Leaves and seeds are burnt in the rural areas, for use as mosquito repellent and as an insecticide. Poultice of the leaves is used for swollen glands, bruises and sprains. 2025-1-2  TOBACCO It is the dried leaves of Nicotiana tabaccum. It is widely cultivated in India for commercial tobacco production it is tropical in origin and thrives best in warm climates. Though it is grown under a wide variety of conditions, thrives best in tropical, sub tropical and temperate zones. It is a tall leafy annual plant originally grown in South and Central America but now cultivated throughout the world including southern Ontario. There are many species of tobacco. 2025-1-2  TOBACCO Nicotiana tabaccum is used to produce cigarettes It played a part in the religious and social rituals of North American Indians and their sharing of pipe was a gesture of peace and friendship. The Aztac people in Mexico call it Yetl where tobacco powder is rubbed on the skin or a wad of the leaves chewed. Nicotiana species grow naturally in Australia and it is chewed by the aboriginal people. It was introduced to France by Jean Nicot, an ambassador to Portugal. It was from him that the name of the genus was derived It is an important cause of ill health but alcohol and tobacco are important revenue source to the government and in most countries there are large industries concerned with their production and distribution to consumers.. 2025-1-2  Chemical Constituents The principal constituents are Nicotine and anabasine 2025-1-2  Uses Smoking Tobacco manufacture Insecticide 2025-1-2  Senna Leaf It consists of the dried leaflets of Cassia Senna L. Cassia acutifolia and Cassia angustifiola Vahl known respectively in commerce as Alexandria and Tinnevely senna. The senna plants are small shrubs of the family Leguminosae about Im in height with paripinnate compound leaves. C. senna in indigenous to tropical Africa and cultivated in the Sudan, C. angustifolia is indigeous to Somaliland, Arabia, Sind and Punjab and is cultivated bin South India (Tinnevely) Senna has been used since the 9th and the 10th Century and its introduction to medicine due to the Arabian physicians who use both the leaves and pods 2025-1-2 Cultivation, Collection and Preparation Alexandrian senna is collected almost entirely from wild plants in the eastern part of Kordofan province, in the White Nile province and along the course of Nile from Khartoum to Dongola. Tinnevely is obtained from the cultivated parts of C. angustifolia The cultivated variety has larger and finer leaves. The branches are collected when the fruits are fully formed, but are still unripe, they are rapidly dried in the sun. Senna has been used since the and the 10th Century and its introduction to medicine due to the Arabian physicians who use both the leaves and pods 2025-1-2  The bulk is brought to the omdurman, where it is sold by auction under government supervision it is then cleaned and graded by tossing in sieves and partly by hand picking into (1) whole leaves, (2) whole leaves and half leaves mixed and (3)siftings. The whole leaves are those usually sold to the public while the other grades are used for making galenicals 2025-1-2  MACROSCOPY The plant produces a paripinnate compound leaf about 10cm in length the leaflets are about 2-4cm long and 7-12mm wide and when dried, are pale greyish-green, thin, and brittle lanceolate to ovate-lanceolate in outline, the widest part being below the middle. The margin is entire the apex acute and mucronate. 2025-1-2  MACROSCOPY CONTD They are unequal at the base, and on the under surface the veins are distinct; both surfaces of the leaf are pubescent, small whitish hairs being distinctly visible especially near the veins. Leaves from the cultivated plants are less rigid, thinner and narrower than those from the wild. Alexandrian senna has a faint but characteristic odour and a mucilaginous taste and unpleasant taste 2025-1-2 MICROSCOPY ` Senna leaflets have an isobilateral structure() Epidermal cells have straight walls and may contain mucilage Both surfaces bear scattered, unicellular, non lignified warty hairs up to 260µm long Stomata have 2 cells with their long axis parallel to the pore and sometimes a 3rd and 4th subsidiary cell 2025-1-2  MICROSCOPY 2025-1-2  MICROSCOPY CONTD Mesophyl consists of upper and lower palisade layers and median spongy mesophyll cotrains cluster crystals abouty 15-20 µm in diameter Midrib is biconvex, below the midrib bundle` is a zone of collenchyma cells 2025-1-2  MICROSCOPY CONTD Midrib bundle surrounded by a zone of lignified pericyclic fibres and a sheath of parenchymatous cells containing prism of cacium oxalate crystals 10- 20 µm long Vein Islet number, stomatal index can be used in distinguishing the two species 2025-1-2  Chemical Constituents Sennosides A, B, C, D, Aloe- emodin dianthrone diglycoside Rhein-anthrone-8-glycoside Rhein-8-diglucoside Aloe-emodin-8-glucoside Aloe-emodin-anthrone-diglucoside Rhein-1-glucose 6-Hydroxymusizin glucoside Tinnevellin glucoside 2025-1-2  Chemical Constituents 2025-1-2  Comparision of Alexandrian and Tinnevelly senna leaves Alexandrian senna Tinnevely senna Not > 40mm in length long,greyish Not > 50mm in length green,more assymmetric at base, Yellowish green rather more broken and curled at the Less asymmetric at the base edges, few press nakings Seldom broken and usually flat owing to compression Often show impression due to the mid-vein of other leaflets Microscopical characters Microscopical characters Hairs more numerousd, most of the Hairs less numerous, average stomata have 2 subsidiary cells only distance being about six epidermal VIN 25-29.5 cells SI 11.4-13.0 Stomata have 2 or 3 subsidiary cell respectively in the ratio 7:3 VIN 19.5-22.5 SI 17.1-20.0 Naphtalene glycoside Naphtalene glycoside 6-Hydroxymusizin glycoside present Tinnevelinn glycoside present 2025-1-2  USES Laxatives Purgative (for habitual or occassional use) 2025-1-2  Quiz (5 mins) Mention four different ways of classifying drugs. Give the full meaning of the following Quantitative microscopical parameters: VIN, VTN, SI, SN and PR. 2025-1-2  Assignment Give the structure of all the chemical compounds ever mentioned under leaf drugs. Why do you think the storage conditions for Digitalis leaves are so strict? 2025-1-2