Medicinal Plants Handout PDF

Faculty of Pharmacy Medicinal Plants PHG101 Handout  Content Topic Page № Introduction to Pharmacognosy 1-5 Production of medicinal plants  Environmental conditions 6  Collection of crude dru...

Faculty of Pharmacy Medicinal Plants PHG101 Handout  Content Topic Page № Introduction to Pharmacognosy 1-5 Production of medicinal plants  Environmental conditions 6  Collection of crude drugs 10  Drying & Packing 12  Preservation & Protection 16  Adulteration of crude drugs 19 Primary metabolites Cell Content:  Starch grains: 24  Proteins 25  Calcium oxalate & carbonate crystals 26 Secondary metabolites  Glycosides  Alkaloids 28-31  Volatile oil  Fixed oil  Tannins  Resin & resin combination Plant Histology Dermal Tissue:  Epidermis 32-37  Non-Glandular Hairs  Glandular Hairs  Stomata  Ground Tissue:  Parenchyma 38-39  Collenchyma  Sclerenchyma Vascular Tissue:  Types of vascular bundle  Xylem 40-41  Phloem Plant Taxonomy  Cryptogamae & Spermatophyta  Gymnosperms & Angiosperms 42-46  Monocotyledons & Dicotyledons Families yielding phytopharmaceuticals Selected families for Gymnosperms  Pinaceae 47-48  Ginkgoaceae  Ephedraceae Selected families for Angiosperms (Monocotyledons):  Alliaceae 49  Palmaceae  Zingiberaceae Selected families for Angiosperms (Monocotyledons):  Apiaceae (Umbelliferae)  Asteraceae (Compositae) 50-51  Leguminoseae  Papaveraceae  Rutaceae  Solanaceae 1- Definition of Botany: Botany is the scientific study of plant and plant life. Plants are classified as: What are Medicinal Plants? Medicinal plants are plants that have a therapeutic or curative effect. Medicinal plants can also be called: herbal medicinal plants, herbal remedies, herbal drugs, or herbs. 2- Pharmacognosy Definition: It means the study of natural substances, mainly plants, that have medicinal uses. The word ‘’Pharmacognosy’’ is derived from the Greek:  Pharmacon = a drug,  Gnosis = to acquire knowledge. So, Pharmacognosy means the entire knowledge of drugs. Therefore, Pharmacognosy studies the scientific basis for the use of plants in pharmacy. 1 3- Crude (raw) drug The plant or animal material before it is subjected to extensive processing or modification. Crude drugs are used as therapeutic agents (of medicinal use). Crude drugs are derived from: plant, animal, or mineral origins. 4-Classification of Medicinal plants Medicinal plants (drugs) are classified in different ways to make their study easy. Each of these ways has advantages and disadvantages. Classification Methods Alphabetical Taxonomical Morphological Chemical Pharmacological 2  Classification methods include the following: A- Alphabetical: (According to Latin or English names) This type of classification is employed for dictionaries, pharmacopoeias ……….,..etc. B- Taxonomical: Medicinal plants (drugs) are arranged based on an accepted system of botanical classification, they can be classified in classes, orders, families, genera, and species. C - Morphological: i- Organized drugs: Medicinal plants are divided according to plant organs such as leaves, flowers, herbs, roots, fruits, & seeds. ii- Unorganized drugs: include plant products e.g., dried latex, extracts, gums, resins, oils, waxes… etc. D - Chemical: Medicinal plants (drugs) are arranged according to the main active constituents that the plants contain, e.g. alkaloids, glycosides, tannins, & volatile oils. E - Pharmacological or Therapeutical: The herbal drugs are classified according to their therapeutic uses. Example: Drugs affecting GIT (gastrointestinal tract), heart, kidney, nervous system, …………etc. 5- Origin of drugs A- Biological origin Biological origin or source of a drug is the plant or animal yielding it. Indicates the name of plant & family from which the drug is obtained. The Binomial system for plants naming was devised by Linnus (a Swedish scientist) who gave each plant a name formed of two words. 3  The first word indicates the Genus name and is written with the first letter capital. The second word indicates the species name and is written with the first letter small.  Both words must be either underlined or written in italics. Example: e.g. Atropa belladonna Fam. Solanaceae Sometimes, the genus name may be chosen to indicate a special meaning. Example for a genus: Glycyrrhiza glabra  (from glucos=sweet, riza=root) Also, the species name may be chosen to indicate a special meaning or some striking characteristics of the plant. B - Commercial origin C- Geographical origin Habitat: is the region in which the plant grows. Indigenous = Natural habitat: plants growing in their native countries. Exotic = acclimatized: plants growing in a country other than their native home. The climate (temp., wind, rainfall, light) affects the active constituents. Thus, the active constituents are greatly affected by the region in which the plant grows. 4 6- Official & Unofficial drugs  Official drugs: are the drugs listed in a book, recognized by the government such as the Egyptian Pharmacopeia.  Unofficial drugs: are the drugs not listed in a book recognized by the government. The Pharmacopoeia It is a governmental book that contains a listing of all official drugs, along with their effects & directions for their use. A drug that is not listed in the pharmacopoeia is said to be unofficial. 5  The crude drug, which reaches the pharmaceutical manufacturing line, must pass through various stages. All these steps influence the nature & amount of active constituents present. These stages are: I. Environmental conditions II. Collection III. Drying & Packing IV. Preservation and protection (Storage) I. Environmental conditions Plant growth, development, as well as the nature & amount of active constituents, are affected by many environmental conditions such as: 1. Temperature 2. Water 3. Light 4. Altitude 5. Soil 6. Plant nutrients 7. Plant Growth regulators 1. Temperature  Each plant has its own optimum temperature that is essential for its growth.  According to this optimum temperature, plants are classified into tropical, subtropical, and cold region plants. 2. Water  Water is an important factor for plant growth.  The amount of rainfall & degree of humidity regulates the availability of water to the plant. 6 Water is important for the following reasons: a. Water is a vital factor for all biological reactions. b. Water allows the movement of minerals from the root to all plant’s parts. c. Water represents 80-90% of protoplasm, the living part of the cell. d. Water regulates the plant temperature by transpiration. 3. Light  Light is an essential factor for plant growth.  Plants vary in both the amount & intensity of light, which they need. Why light is essential for plants? a. Plants need light to perform photosynthesis. b. Light influences the quantity of active constituents (glycosides or alkaloids) produced by the plant. E.g. Belladonna gives a higher content of alkaloids in full sunshine rather than it does in shade. c. Light affects the flowering of plants. 4. Altitude Altitude is the height of plant in relation to sea level or ground level. Altitude influences the temperature & affects the formation of active constituents. E.g., Cinchona, that grows at high levels, produces alkaloids, while at low levels, the plant grows well, but it doesn’t produce alkaloids. 5. Soil A soil is a heterogeneous mixture of organic particles, living organisms & minerals. Different plants vary in their soil and nutritive requirements. Three important basic characteristics of soils are their physical, chemical and microbiological properties. According to particle size, soil ranges from clay to sand to gravel. Particle size is one factor affecting water-holding capacity. Water capacity: is the amount of water that remains in soil after any excess has drained away. 7  6. Plant nutrients All nutritive requirements of plants, starting from seed germination to maturity, are commonly supplied by the soil. Nutrients commonly supplied by the soil are classified into four types: A- Main nutrients or macro elements: N, P, K  These main elements are needed in large amounts.  Deficiency of N produces Yellowing (Chlorosis)  Deficiency of P causes reduction of the plant size.  Deficiency of K decreases carbohydrate synthesis. B- Active elements: Ca, Mg, S These elements are not to be added to the soil as their amounts found in the seed coat are sufficient. Plants need little amount of these elements for their growth. C- Microelements: Cu, Mn, Zn, Fe, Co, these are elements that are needed in very small amounts. Excess of them is toxic to the plants. D- Inactive elements: Na, Al, Si, I These inactive elements are only required by certain plants, not all plants. 7. Plant Growth Regulators (Plant hormones) The growth and development of plants is regulated by several chemical substances which together exert a complex interaction to meet the needs of the plant. Five groups of plant growth regulators are well known, they include: A- Growth stimulators: B- Growth Inhibitors: i. Auxins iv. Abscisic acid ii. Gibberellins (GA) v. Ethylene gas iii. Cytokinins A. Growth stimulators i. Auxins: These are growth promoting substances, which were found to possess properties like indole-3- acetic acid (IAA), which is considered as the major auxin of plants, IAA is found in actively growing tissues that regulates the growth. Synthetic auxins include indole-3-butyric acid, and naphthalene-1-acetic acid (NAA). 8  Typical effects of auxins:  Auxins stimulates the cell growth (cell elongation) i.e. stem length.  They are responsible for formation of secondary metabolites, e.g. seedling and young plant of Mentha piperita, when treated with (NAA) naphthalene acetic acid, increased the yield of oil by 30-50%.  They can be used as herbicide, when present in high concentration. ii- Gibberellins They are synthesized in leaves and have the following effects:  Gibberellins stimulate the flowering stages, before the normal flowering dates.  They increase the length of the stem.  They increase the production of secondary metabolites e.g. volatile oils & glycosides. iii- Cytokinins It is the cell division hormone.  Cytokinins stimulate mitosis & cell division.  They delay the plant’s aging process. B. Growth inhibitors Natural growth inhibitors are present in plants; they affect bud opening, seed germination and development of dormancy. (The state in which the plant is alive, but not actively growing). i. Abscisic acid: It induces seed dormancy and inhibits shoot growth. ii. Ethylene gas: It is the only gaseous hormone affecting plants; it is evolved by stored apples and inhibited the growth of potato shoots enclosed with them. 9 II. Collection of Crude drugs  The qualitative and quantitative composition of plants may change during the growing season.  To ensure the maximum quality in crude drugs, it is important that the plants which produce them are collected in the right season and at the appropriate stage of their development cycle.  Although the active principles of the different plants may be distributed in several or in all parts of the plant, they are more concentrated in certain organs, and these organs are usually collected as commercial drug. Drugs can be collected from wild or cultivated plants. Drugs collected from wild plants have the following advantages:  Cheap source.  Plants grow in their native habitat.  Plants contain active constituents of best quality.  Plants contain higher percentage of active constituents. Disadvantages of cultivation:  High cost of production (high cost of labours and land).  Medicinal plants need a particular environment, which can’t be afforded in cultivation. 10  Comparison between Cultivated & Wild plants: Cultivated Plants Wild Plants Cultivated plants provide a large Wild plants are scattered over area of medicinal plants in an unlimited areas (deserts, forests, accessible area. or seas) that may be difficult to reach and be collected. Cultivated plants provide a Collection of wild plants may lead regular and sufficient supply to to deficiency in certain medicinal meet the market demands. plants. All operations including collection, Unskilled people carry out the drying and storage are carried out collection which may lead to the by skilled people, also it ensures collection of wrong plant at wrong the purity of the product. time & the plant may be liable to adulteration. All steps are done near a Transportation to the factory may pharmaceutical factory so the take a long journey that require plant could be taken directly from effort, cost and may lead to loss of the field to the factory. active constituent due to deterioration by storage or careless handling. Factors affecting collection: A. Time 1. Time of the year (season): E.g1. Rhubarb: In winter: there are no anthraquinones. but contain only anthranols (emetics, cause gripping) In warm weather (spring, summer): anthranols are converted by oxidation into anthraquinones (the active constituents responsible for the laxative effect). E.g2. Colchicum corm: In spring: the active constituent  colchicine In autumn:  the active constituent  starch 11 2. The time of the day: E.g1. Digitalis leaves: When collected in the afternoon → high % of glycosides. when collected at night → low % of glycosides, (hydrolysis) E.g2. Solanaceous leaves: When collected in the morning → high % of alkaloids are present. B. Stage of Maturity: Maturity: Certain drugs contain the maximum amount of the active constituents at a definite stage of plant growth and must be collected at this stage.  Clove flower → collected in bud form.  Santonica flower → collected unexpanded flower head. III. Drying & Packing A- Drying of crude Drugs: Fresh organs, when collected are either used as such or dried to be used later. Why drugs are dried? Drugs are dried for the following reasons:  Drying aids in their preservation, to prevent the growth of micro- organism such as bacteria and fungi.  Drying fixes their constituents, to inhibit the enzymatic or hydrolytic reactions that might alter the chemical composition of the drug.  Drying facilitates the grinding into fine powder which reduces the weight to facilitate packing, transport, and storage. Drying is controlled by the nature of the material to be dried and the desired appearance of the finished product. There are two main points to be considered for successful drying: 1. Controlling of temperature 2. Regulating of air flow or ventilation. 12 Methods of drying: There are two methods of drying: Natural Drying and Artificial Drying 1. Natural Drying: It is the use of climatic heat; depending on the weather, thus the drug is dried in open air by: A. Exposure to sun: except if the active constituents or colour are affected. B. Shade drying by putting on the floor or trays in a single layer to retain the natural colour of the drug and preserve its sensitive active constituents. 2. Artificial Drying: Artificial Drying is necessary in tropical countries, where humidity is very high. Advantages & disadvantages of natural & artificial drying: Point of comparison Natural Drying ArtificiaDrying Advantage(s) Cheap -Rapid -It is done at controlled temperature -It stops enzymatic hydrolysis Disadvantage(s) It takes long time Methods of Artificial Drying: a) Chemical drying: The drug is placed in a desiccator with a dehydrating agent (quick lime, which form dry atmosphere. b) Physical drying: It involves the use of elevated temperature and/ or reduced pressure (vacuum). It may be applied by: i. Direct heat. ii. Drying chamber. iii. Drying oven. iv. Freeze drying (Lyophilization). v. Pneumatic High Speed Drying (Flash Drying). 13  Physical Drying may be applied by: i. Direct heat: Drying is done by open fires or stoves, they are used for drugs with heat-stable active constituents. Disadvantage: Temperature is uncontrolled. ii. Drying chamber: It is a small chamber with shelves, door, windows and hot water pipes. There must be a space of at least 15 cm between superimposed trays, so as air can circulate freely. Advantages:  Temperature is controlled.  Drugs are not affected by any weather changes. iii. Drying oven: It is a small cabinet having a source of heat device for circulating air. When evacuated (vacuum oven) it is rapidly and efficiently performed drying at lower temperature (advantage). iv. Freeze drying: (Lyophilization) The drug is subjected to high vacuum before & after freezing until completely dry. Very low temperature and high vacuum are used. Advantage: It retains the colour & texture of the product. It is used for biological fluids, & drugs containing unstable constituents. 14 v. Pneumatic High Speed Drying (Flash Drying) The drug is dried by exposure to high temperature 800oC for a fraction of a second under reduced pressure. It is used for sensitive drugs. Changes in Drugs during and after drying: 1. Size and weight: reduction in size and weight occur due to loss of water. 2. Shape and appearance: Some drugs shrivel and shrink when dried, and the surface gets wrinkled and reticulated. The inner surface of most barks gets cured and become rolled as the inner tissues are soft and outer ones are hard. 3. Colour: Generally, on drying the drug becomes darker in colour, but in certain cases a total change may occur. E.g., Tea leaves: dark, black (on slow drying), green (rapid drying): Reason: Presence of an oxidase enzyme (phlobatannins are changed into phlobaphene, black). 4. Odour: Drying may change the natural odour. E.g1. Vanilla pods: are odourless when fresh, while they become fragrant, pleasant when dry due to formation of vanillin. E.g2. Digitalis and Hyoscyamus: lose their undesirable odour. 15 5. Constituents: Generally no change in constituents on drying. Sometimes change occur: E.g., Fresh Vanilla pods contain: a. Glucovanillin glycoside: on drying →It is hydrolysed → vanillin b. Glucovanillic alcohol: on drying →It is oxidized to → vanillin. 6. Taste: Taste of the drug may be altered. E.g., Gentian is very bitter when fresh, → on drying: bitter taste → sweet & pleasant. IV. Preservation and protection: Storage represents the last step in the handling of crude drugs before being used, and it is the most important stage. Proper storage and preservation are important factors  lead to high degree of quality of drugs. Drugs usually deteriorate either slowly or rapidly during storage with few exceptions: E.g., Cascara and Frangula, they should only be used after certain period of storage.. The general undesirable changes which may occur on storage are: Drugs containing volatile oils gradually lose their aroma. Ergot acquires disagreeable aroma. Digitalis leaves may lose their activity. Drugs containing fixed oil (fatty seeds) may be rancid. Certain pharmacopeias give well, clear instructions concerning time of storage, after which drugs shouldn’t be used. Crude drugs must be stored: 1. In well close containers (air-tight). 2. Away from light (amber-glass containers), moisture and dust. 3. At low temperature. 4. Away from insects. 16  Improper methods of storage: The principal factors responsible for deterioration of drugs are: 1. Physicochemical factors  moisture (humidity), heat, air and light. 2. Biological factors  fungi, bacteria, insects and rodents. 1. Physicochemical factors a. Moisture may cause:  Hydrolysis of active constituents by enzymes.  Growth and nourishment of bacteria and fungi. To overcome the effect of hydrolysis stabilization of the drug may be carried by:  Enclosing dehydrating agents as lime or calcium chloride in the container of the stored drug.  Destroying enzymes by immersing the fresh drug in alcohol. b. Light  Photochemical reactions may occur that affect delicate drugs.  Digitalis leaves lose the activity more rapidly in sun light.  To avoid the effects of light, drugs should be stored in dark or by the use of opaque or amber coloured glass containers. c. Temperature  A slight raise in temperature will activate the enzymatic action.  Drugs affected with the rise in temperature are those containing volatile oil such as clove and chamomile. d. Air  Oxygen of air has an oxidation effect on the active constituents of some drugs leading to lowering the quality of products.  Oxidative changes are sometimes required to produce the active constituents as in case of Frangula bark. 17 2. Biological factors: A. Bacteria and fungi  Sufficient moisture content is essential for bacteria or fungal infestation.  Bacteria or fungal infestation may change the physical properties of the drug as colour and texture.  The presence of fungi is indicated by their hyphae. B. Insects could be controlled by one of the following methods: i. Heat treatment: It is done by exposing the crude drugs to temperature 60-65oC which can kill insects as well as their eggs. (Should not be used for thermolabile or volatile constituents) ii. Fumigation: Drugs are subjected to poisonous gas (HCN) or liquid vapor in a closed room. Drawback: This method kills the insects but not their eggs. iii. Liming: Drugs are covered by a coat of lime before storage which block the respiratory system of insects and larvae (to prevent insect-attack), e.g., Nutmeg, Ginger. iv. Low temperature storage (refrigeration or freezing): It is the most suitable method; it kills all stages of insects; it does not affect the active constituents. C. Spoilage by rodents: (rats & mice) The presence of filth of rodents (hairs, excreta) can cause the spoilage of drugs, they must be rejected. A.N.T.U.  alpha naphthyl thiourea, is used to eliminate rats and mice (rodenticide). N.B. Some drugs are sterilized before storage. 18  Adulteration of crude drugs Adulteration is the debasement of any article. Debasement is the process of spoiling something or reducing its value by combining it with another material. Adulteration may occur when the drug is unavailable or when the price of the drug is high. The adulterant must be some material, which is cheap and available in large amount. Adulteration involves: 1) Sophistication (True adulteration) 2) Substitution 3) Admixture 4) Deterioration 1) Sophistication (True adulteration) The addition of an inferior material to any article with intention to defraud E.g. Addition of wheat flour (to add volume), capsicum (to restore the pungency) & curcuma (to maintain the colour) to powdered ginger. 19 2) Substitution  An entirely different article is used instead of the required drug.  Substitution is different from sophistication, as none of the true article is present. Substitution is carried out in different ways: a. Substitution with inferior quality It is the use of morphologically resemble, different inferior commercial varieties (may or may not have any chemical or therapeutic potential as that of the original drugs). An entirely lower quality e.g. Arabian Senna is used to adulterate genuine Senna. b. Substitution by exhausted drugs Exhausted drug: The plant material is mixed with drug that is devoid of any medicinally active constituents as they are already extracted out.  Volatile oil containing drugs: E.g. Clove from which part of the oil has been removed by distillation. (Partially exhausted). c. Substitution by an inferior, cheap morphologically similar but different substances Substitution with a drug having no relation to the genuine drugs, may or may not have any therapeutic or chemical components.  E.g.,1: use of Cotton seed oils instead of Olive oil.  E.g.,2: use of Scopolia leaves instead of belladonna leaves. 20 3) Admixture: The addition of an article to another through accident, ignorance or carelessness. If the addition is intended, it is sophistication. Admixture may occur through: a. Faulty collection as collecting the drug not at the proper time, E.g., Collecting Solanaceous leaves in summer. b. Faulty collection of other parts of the same plants by mistake E.g., stems, stalks, aerial parts with leaf drugs. c. Collection from other plants by mistake or ignorance of collectors. 4) Deterioration: An impairment of the quality of a drug by destruction of active constituents by physical process as distillation, extraction, aging, moisture, heat, fungi, insect or other means.  E.g.1 Coffee which lost caffeine through over-roasting.  E.g.2 Powdered Squill hardened through absorption of moisture. a) Spoilage: A special form of deterioration in which the quality of a drug is impaired or destroyed by the action of bacteria or fungi, making it unsuitable for human consumption. b) Inferiority: Inferiority refers to sub-standard drug. It is any drug not conforming to standards, means containing fewer amounts of active constituents. E.g.,1 the dried seeds of Nux vomica containing less than 1.15% strychnine. c) Using synthetic drugs Certain synthetic articles are added to fortify the drug e.g. as adding Citral to lemon oil. 21 Detection of adulterants It involves the identification of the adulterant and determination of the quality of the drug. Several methods are used such as: 1. Macro and micro morphology. 2. Solubility. 3. Qualitative tests. 4. Quantitative tests. 5. Yield to solvents. 6. Pharmacopeial constants (Total ash, water soluble & insoluble ash, acid soluble & insoluble ash). 7. Comparison with an authentic sample of the drug. 22  Primary metabolites Secondary metabolites 1. Primary metabolites are 1. These are non-essential. essential for life process. (Act as defense mechanism 2. (Growth & division of the cells) and to attract pollinators) 3. These are produced 2. These compounds don't have continuously during the growth continuous production. phase and are involved in However, they are produced primary metabolic processes during non-growth phase of such as respiration and cells. photosynthesis, etc. 4. Produced in large quantities, 3. Produced in small quantities, so their extraction is easy. so their extraction is difficult. 5. Same in all plants. 4. 4. different (unique) in certain plants. 6. Proteins, carbohydrates and 5. 5. Alkaloids, glycosides, fixed lipids are the main primary oils, volatile oils, and tannins, metabolites. etc. 23  Cell Content 1. Starch Starch is tested by Iodine test (microchemical test); it gives bluish violet color. Potato Wheat Maize Rice Size Largest Large Medium Small Lenticular or Shape Oval round Polyhedral Polyhedral Small Stellate Hilum eccentric Small centric centric Absent Very fine in Striation Clear large particles Absent Absent Aggregation Simple & Simple & Simple & Simple & compound compound compound compound Drawing 24 1. Protein A. Shapes of protein: 1. Aleurone grains:  The crystalloid (angular shape).  The globoid (rounded shape). Each aleurone grain has a bounding membrane enclosing more or less angular body, the crystalloid and a smaller rounded one, the globoid. 2. Amorphous protein: with no definite shape. B. Chemical test for proteins: Protein is tested by Picric acid; it gives yellow color. 25 3. Crystals: A. Calcium oxalate crystals: It is considered one of the most important cell contents through which we can differentiate between different drugs, because they have different shapes, they can be:  Clusters.  Styloid (prisms & twin prisms).  Raphides (Needles). B. Calcium carbonate (Cystolith): Calcium carbonate could be detected by dil. HCL, it gives effervescence. 26  Carbohydrates  Definition: Composed of C, H & O, and ratio of H:O=2:1 as water, they serve as the main energy stores.  Classification: -Simple sugars as glucose and fructose -Disaccharides as lactose -Polysaccharides as starches & cellulose -Special modified form as gum & mucilage  Uses: Demulcent &produce gels that are utilized in medicine and in food preparations.  Chemical tests: General test for carbohydrates: Molisch test, which gives violet ring. Test for reducing character of carbohydrates: Fehling test, which gives orange, red, brown ppt. (Change in the blue color of Fehling) 27  Secondary metabolites 1- Glycosides  Definition: Glycosides are composed of two parts: carbohydrate (sugar) residue called "glycone", and a non-carbohydrate (non-sugar) residue called "aglycone, genin" in the same molecule. There are various classes of glycosides, with different uses depending on the type of aglycone.  Classification: - Aglycone nucleus (phenolic, anthraquinones,…….)  Number of sugar part (Mono, di, tri, tetra, polysaccharides)  Linkage type (O, C, S, N)  Sugar type (glucoside, rhamnoside,………...)  Others (saponin, cardiac, flavonoids)  Uses: -Laxative (Anthraquinones in Senna) - Tonic of capillaries & antioxidant (Flavonoids in Citrus plants)  Cardiotonic (Cardiac glycosides in Digitalis)  Expectorant (Saponins in Liquorice)  Anticoagulant (Coumarins in Chamomile)  Hypocholesterolemic (Linnamarin “Cyanogenic glycoside” in Linseed) Chemical tests Borntrager’s KOH test Keller Froth test NaOH test Linnamrin test Killian’s test test 28  2- Alkaloids  Definition:  Classification: o According to main nucleus: Phenolic (morphine), tropane ester (atropine)……..etc. o According to nature: Volatile (nicotine) and non-volatile  Uses: - Narcotic analgesic (Morphine in Opium) - Mydriatic & spasmolytic (Atropine in Belladonna) - Nasal decongestant (Ephedrine in Ephedra)  Chemical tests: General test for alkaloids: Mayer’s test, it gives creamy white ppt with most of alkaloids. Specific test for solanaceous alkaloids: Vitali’s test, it gives violet color that fades by time with solanaceous alkaloids.  Solanaceous alkaloids are present in plants belonging to the family Solanaceae (Belladonna, Datura & Hyoscyamus). 29  3-Volatile Oils 4- Fixed Oils Point of comparison 3- Volatile Oil 4- Fixed oil Definition Odoriferous Triglycerides liquids or solids. esters of fatty acids. Volatility Volatile Non-volatile Stain on filter paper Produce volatile Produce stain on filter paper permanent stain on filter paper Saponification with alkali Not saponified with Saponified with alkali alkali Classification Various chemical Saturated & nature (alcohols, unsaturated aldehyde, ketones, fatty acids esters,...) Uses -Spasmolytic (Oil of -decreases the Mentha) blood - Counter irritant cholesterol (Oil of Black level (Oil of mustard) Linseed) - Bactericidal (Oil of Thyme) Sudan III Red color Red color 30  5-Tannins  Definition: Polyphenolic compounds, that precipitate proteins, and make complex with heavy metals as iron & calcium.  Classification: -Condensed & hydrolysable tannins. Uses: Astringent & antiseptic so used as antidiarrheal & in wounds healing, as tea & coffee examples of plants that contain tannins.  Chemical tests: Ferric chloride test Bluish black color with Olive green color with hydrolysable tannins condensed tannins 6-Resin & resin combinations  Definition: Amorphous products of complex chemical nature.  Classification: - Resin (e.g., colophony) - Oleo resin (volatile oil + resin) - Oleo gum resin (Volatile oil + gum + resin as Myrrh)  Uses: -Plaster & ointments (as colophony from Pinus) -In perfumes (as Myrrh) 31  Types of plant cells Dermal Vascular Ground cells cells cells Epidermal cells Parenchyma Xylem Stomata Collenchyma Phloem Hairs Sclerenchyma 32  Dermal Tissue 1. Epidermis:  Epidermis layer protects the underlying cells.  It is a transparent single outermost layer of cells which covers the whole plant.  It is covered by a waxy waterproof cuticle made up of cutin (to prevent the loss of moisture). 2. Hairs or Trichomes:  These are projections outside the epidermal cells.  They are either: Papi Trichomes llae (hairs) Short projections. Long projections.  Non-glandular hairs for protection.  Glandular hairs  for secretion. How can you describe any non-glandular or glandular hair? 1. Mention the presence or absence of head (Glandular or Non-glandular). 2. How many cells are present? (uni, bi, multi-cellular). 3. Cells are arranged on how many rows? (uni, bi, pluri-seriate) 33  Non-Glandular Hairs Classification according to the number of cells Unicellular Multicellular (Formed of one cell) (Formed of > 1 cells) A- Simple: Unbranched Branched 1. Warty unicellular non- 1. T-shaped hair 1. Simple glandular hair 2. Stellate (E.g. Senna and Anise) 2. Cystolith hair 2. Twin hair 3. Peltate (E.g. Cannabis) 3. Shaggy non- glandular hair 4. Candelabra B- Branched. (E.g. Cumen) 34  Glandular Hairs Classification according to number of rows: Uniseriate stalk Biseriate Pluriseriate stalk Branched (Cells are arranged on 1 stalk (Multiseriate)(>2 stalk & biseriate rows) row) head (On 2 rows) Unicellular Multicellular Example: Example: Example: head head Compositae Shaggy glandular Branched Example: Example: hair hair Glandular hair 1. Digitalis 1. Labiaceous hair 2. Belladonn (Characteristic (E.g. a (E.g. Mentha) to Family Hyoscyamus) (E.g. Cannabis) Compositae, 2. Clavate hair: as in Chamomile) (Characteristic to Family Solanaceae, as in Datura, Belladonna, & Hyoscyamus) 35  3. Stomata Stomata: pores that are found between the epidermal cells and responsible forgaseous exchange. 3.1. Anatomical structure of stomata:  Stoma “opening”.  Two guard cells.  Subsidiary cells. 3.2. Shape of guard cells: Dumbbell Shaped Bean or kidney shaped Found in “Monocots plants” Found in “Dicots plants” 3.3. Types of stomata in dicots plants: are classified according to: 1. Number of subsidiary cells: Either 2 or more. 2. Arrangement/size of subsidiary cells 36 Classification according to the number, arrangement & size of subsidiary cells: 1. Two subsidiary cells Paracytic: The two subsidiary cells are parallel to the guardcells. (e.g., Senna) Diacytic: The two subsidiary cells are perpendicular to theguard cells. (e.g., Mentha) Paracytic stomata Diacytic stomata 2. More than 2 subsidiary cells: Anomocytic: The subsidiary cells are almost equal in size. Anisocytic: The subsidiary cells are different in size (one cell is smaller than the others). (e.g., Solanaceous drugs) Anomocytic stomata Anisocytic stomata 37  Ground tissue 1-Parenchyma cells: Characters: they are characterized by having thin 1ry cellulosic wall, large lumen & distinct intercellular spaces. Test: Cellulose + Chlorozinc iodide--- Blue color Types: -Normal Parenchyma -Chlorenchyma (contains chlorophyll) -Aerenchyma (with extensive large intercellular space) Normal Parenchyma Aerenchyma Chlorenchyma Occurrence: These cells are present in the cortex, pith, xylem, phloem, and mesophyll of the leaves. Function: Parenchyma cells are important for food storage (as starch), they also permit gaseous exchange through intercellular spaces. Also, photosynthesis takes place in Chlorenchyma. 2-Collenchyma cells: Characters: they are characterized by having thick cellulosic wall & pectin, they have narrow lumen, & no intercellular spaces. Test: Cellulose + Chlorozinc iodide--- Blue color Types: -Angular (thickened at corners) -lamellar (thickened at tangential wall) -Lacunar (thickened facing all spaces around the cell) 38 Occurrence: they are usually present beneath epidermis in the midrib & petiole of the leaf, & the cortex of the stem. Function: Collenchyma cells are important for supporting the plant tissues, also photosynthesis takes place when chlorophyll is present. 3-Sclerenchyma cells: Characters: Sclerenchyma cells are described as dead cells with thick lignified walls, they are characterized by having narrow lumen with no intercellular spaces. Test: Lignin + Phloroglucin /conc Hcl Red color Types: -Sclereids (Short isodiametric) -Fibers (long, narrow with pointed apices) Occurrence: Sclereids form the hard coats of seeds & fruits. -Fibers are usually found in xylem & phloem regions. Function: Sclerenchyma cells are essential for supporting, strengthening & hardening the plant tissues. 39  Vascular tissue The vascular tissues of higher plants (Kingdom Plantae) are divided into two sections: xylem and phloem. These 2 are found in the vascular bundles of plants. Types of vascular bundle In Monocot plants: Closed vascular bundle. In Dicot plants: Open vascular bundle. Xylem: Characters: Xylem is characterized by having 1ry thick cellulosic walls further strengthened by 2ry lignified walls. Test: Lignin + Phloroglucin/c.HCl--- Red color Structure: Xylem consists of two types of cells: Vessels & tracheids. Tracheids are like xylem vessels, they have thick, lignified walls and pitted. Their walls are perforated so that water can flow from one tracheid to the next. 40 Types of Xylem vessels: The secondary walls of the xylem vessels(lignin) are deposited in spirals and rings and are usually perforated by pits. Xylem vessels vary according to the shape of 2ry thickening into annular, spiral, scalariform, reticulate, pitted. Function: Xylem conducts water and dissolved minerals from the roots to all the other parts of the plant. In woody plants, serves to give strength to the trunk. Phloem: Characters: Phloem is characterized by having cellulosic walls. Test: Cellulose + Chlorozinc iodide--- blue color Structure: Phloem is composed of: -Vertically stacked Sieve elements are so-named, because their walls are perforated to allow connections between cells. -Companion cells, that move sugars into and out of the sieve elements. Function: - Phloem conducts the products of photosynthesis - sugars from the place where they are manufactured e.g., leaves, to the places where they are consumed. 41 What is Taxonomy?  Taxonomy is the science that finds, describes, classifies, and names living things.  The species is the basic unit for studying relationships among living organisms.  Taxonomy is the science of naming organisms and their correct classification. Importance of Taxonomy:  The exact naming (taxonomy) and understanding of the species' relationship to other species is an essential basis for pharmacognostical work.  Allows the correct identification of a botanical drug, and consequently is the basis for further pharmacological, phytochemical, analytical or clinical studies. 42  How to relate an identified organism to the botanical classification? Senna Garlic Saw Chamomile palmeto 43 Differences between Gymnosperms & Angiosperms: Gymnosperms Angiosperms The seeds are not enclosed in The seeds are covered by closed carpels, the seeds are naked. carpels. Seed dispersal occurs by wind. Seed dispersal occurs by animals. Gymnosperms comprise the Angiosperms comprise the largest smallest group of plants. group of plants. At least 240,000 species represent Only about 750 species represent angiosperms, they are split into gymnosperms. two large groups Dicotyledons & Monocotyledons. 44 Angiosperms are subclassified into Monocotyledons & dicotyledons: Difference between roots in Moncocotyledons & dicotyledons: Monocotyledons Dicotyledons Fibrous roots Tap roots 45 Differences in stems between Monocotyledons & Dicotyledons: Point of Comparison Monocot Dicot Ground tissue Undifferentiated to Differentiated into layers layers Vascular bundle 1. Number Numerous Few 2. Arrangement Scattered in Arranged in one ring. ground tissue 3. Size Small Large Nature of vascular Closed Open bundle Cambium Absent Present Pith Absent Present in the center 46  Plants belonging to the same family often contain similar types of compounds.  For example, many members of the Solanaceae family are known to contain biologically active alkaloids.  Certain families (out of a total of more than 200 recognized families) have been selected as Families yielding important phytopharmaceuticals and are presented within the grouping’s angiosperms and gymnosperms. 47  Selected families for Gymnosperms: Family Plant Medicinal Uses Active Chemical Examples constituents Tests Pinaceae Pinus sp. Used in - Turpentine oil manufacture of - Resin called plasters & Colophony ointments. Ginkgoaceae Ginkgo biloba Increases blood -Ginkgolides circulation to the glycosides brain so used for its memory- improving properties (Treatment of Alzeheimer’s disease) Ephedraceae Ephedra sp. -Antiasthmatic -Ephedrine - Nasal alkaloid decongestant Side effect: Hypertensive (increases the blood pressure) 48  Selected families for Angiosperms (Monocotyledones): Family Plant Medicinal Uses Active Chemical Examples constituents Tests Alliaceae Garlic, Onion Hypocholesterolemic, Sulphur- antihypertensive, containing bactericidal antibiotic compounds, especially alliin & allicin \\\ Palmaceae Saw palmetto Antioxidants, difficulty Polyphenols in urination in benign prostatic hyperplasia Zingiberaceae Curcuma, Used for Curcumin turmeric inflammatory & liver diseases. Cardamom Used in Volatile oil, gastrointestinal terpenes as disorders, Limonene & carminative & cineol antispasmodic. Ginger Used in motion Volatile oil, sickness, and gingerol gastrointestinal disorders. 49  Selected families for Angiosperms (Dicotyledones): Family Plant Medicinal Uses Active Chemical Examples constituents Tests Apiaceae Anise Carminative & Volatile oil (Umbelliferae) antispasmodic Caraway Asteraceae Cynara Treatment of liver Cynarin (Compositae) (Artichoke) and gallbladder complaints Echinacea Immunostimulant, Echinacin, alkyl treatment of amides respiratory diseases Leguminosae Senna Strong laxative Anthraquinones Liquorice Expectorant Saponin glycoside (Glycyrrhizin) Peptic ulcer Flavonoid (Liquiritin) 50  Family Plant Medicinal Uses Active Chemical Examples constituents Tests Papaveraceae Opium poppy Narcotic analgesic Morphine alkaloid Rutaceae Pilocarpus Used in Pilocarpine jaborandi ophthalmology as alkaloid myotic (constricts the eye pupil) Solanaceae Belladonna Mydriatic (dilates Solanaceous the eye pupil) alkaloids (atropine) Datura Spasmolytic and Solanaceous used for motion alkaloids sickness (hyoscine) 51  Hyoscyamus Spasmolytic and Solanaceous used for motion alkaloids sickness (hyoscyamine) References: o Chemistry of Natural Products: Phytochemistry and Pharmacognosy of Medicinal Plants (De Gruyter Stem) 1st Edition, Mayuri, N. and Lalith , J. , publisher De Gruyter, May 3, 2022. o Malviya, S. and Rawat,S. “Textbook of Pharmacognosy and Phytochemistry” Oxford & IBH Publishing Company Private, Limited, Jan 30, 2020. o Dilipkumar Pal, Amit Kumar Nayak., Bioactive Natural Products for Pharmaceutical Applications, Springer Nature, 2020. o Heinrich, M.; Barnes, J. and Williamson, E.M. “Fundamentals of Pharmacognosy and Phytotherapy” Churchill Livingstone, Elsevier Limited; 3rd edition, 2018. o Mandal, S.C., Mandal, V, Konishi, K., Natural Products and Drug Discovery, Editor Annika Hess, published by Mica Haley, Elsevier, Ltd. 2018. o Ahmed, S.; Hasan, M. M.; Crude drug adulteration: a concise review, World Journal of Pharmacy and Pharmaceutical Sciences Vol 4, (10), 2015. o Ali, M.; Textbook of Pharmacognosy, Publishers CBS & Distributors, 2012. o Evans, W.C.; “Trease and Evans Pharmacognosy." 16th Edition, edited by William C. Evans, Elsevier, 2009. 52