Pharmacognosy I Lecture 1 PDF

Lecture 1 PHARMACOGNOSY I PPC (101c) 1st YEAR STUDENTS (Clinical) Definition Pharmacognosy Pharmacognosy is the branch of pharmaceutical science that studies medicinal or crude drugs derived from natural sources:  pla...

Lecture 1 PHARMACOGNOSY I PPC (101c) 1st YEAR STUDENTS (Clinical) Definition Pharmacognosy Pharmacognosy is the branch of pharmaceutical science that studies medicinal or crude drugs derived from natural sources:  plants  animals  minerals  marine sources  microorganisms Related to the treatment they receive during their passage from the producer to the distributor or pharmacist. Including:  history, methods of cultivation and collection  physical, chemical and structural characters  processing (extraction and preparing the active constituents) and preservation  uses of crude drugs.  Pharmacognosy The word Pharmacognosy is derived from the Greek "Pharmakon", meaning a drug or poison and "gnosis or gignosco" meaning to acquire a knowledge of and literally meaning "the entire knowledge of drug". Pharmacognosy has an important role in the development of different sciences: Originally a branch of medicine, pharmacology. Applied science, dependent on botany and chemistry. Requires knowledge of geography, history, physics, etc.  History of Pharmacognosy The primitive man had a good knowledge of the vegetable kingdom of his surroundings. Primitive man learnt which plants were good for food and which were poisonous.  He also found that some plants (spices or condiments) preserved meat and disguised unpleasant flavors and that other plants could be used for making extracts useful as arrow-or spear-poison (e.g. from species of Strophanthus, Acocanthera and Conium) Strophanthus seeds had been used by the natives of Central Africa as an arrow- poison. Priest-physicians and herbalists learned by trial and error that some plants had dispelled the symptoms of disease. Folk medicine emerged by acquiring knowledges of crude drugs. Ancient Egyptian period These three papyrus describes 400 primary materials constitute "Egyptian pharmacopeia" of the ancient Egyptians. A- Those of an animal origin e.g. blood, meat, milk, honey and excreta. B- Materials of vegetable origin e.g. Aloes, Gum, Poppy, Pomegranate, Coriander, Cumin, Palms, Onion, Anise, Grapes, Melon, Castor. They used all the vegetable organs e.g. roots, rhizomes, flowers, leaves, fruits, seeds, as well as oils, and ashes. Also, they applied the mineral stones e.g. sulphur, salt. They applied their medicaments in the form of powders, pills, suppositories, creams, cakes, pastes and ointments. The Babylonians The Babylonian medicine was known (Laws of Hamorabi 772 B.C.). the drugs used were mainly of vegetable origin. The drugs used include 250 materials of plant, and 180 materials of animal source. Many of these drugs were known to the ancient Egyptians. The Babylonian formulae showed no quantities or weights of the ingredients (c.f. Egyptian formulae). It seems that these were left to the ability of the dispenser and his personal knowledge. The application of the drugs in the form of a decoction, usually administered before sunrise, as the decoctions were prepared by night. The drugs were usually mixed with honey, water, oil or wine. Old Indian medicine The "Riveda" and Ayurveda (Acoko 2000 B.C.), contained the sacred medicinal plants. The collection of plant materials was done only by an innocent, pure, religious person. The fresh plants were considered to be the most effective. The most celebrated Indian drugs were; Sandal wood, Clove, Pepper, Cardamom, Caraway, Ginger, Benzoin, Cannabis, Castor oil, Sesame oil, Aloes, etc... The old Chinese medicine Beside the famous acupuncture, the Chinese medicine is very acknowledged for the herbal medicine. The Pen Ts'ao Kang Moa 1000 B.C. contained an incredible number of medicinal plants and drugs of animal origin. Among the plants and minerals highly esteemed for its magic health including power were; Ginseng, Rhubarb, Ephedra, Star Anise, Pomegranate, Aconite.... Opium is a very old Chinese drug for diarrhea and dysentery. The Greek and Romans Pythagoras (560 B.C.) used drugs as Mustard and Squill, etc.... Hippocrates (466 B.C.) was familiar with numerous drugs, and wrote "Corpus Hipocraticum 460 B.C.". The Greek Empire was followed by that of the Romans, and Dioscorides who was a Greek by birth he was the first to describe drugs and his work "Greek Herbal of Dioscorides" included 5000 medicinal plants in addition to animal and mineral drugs. Pliny who lived about the same time as Dioscorides, was also an eminent author of natural history. Galen (134- 200 A.C.) was a physician and to him is ascribed the use of "Galenical preparations".  Islamic Contribution In Islamic writings were found the first beginnings of chemistry, the name of which is derived from an Arabic word "Kemia"; as were also such familiar words alcohol and alkali. The Arabs added numerous new plants and medicaments to those already known to the Greeks and Romans. The pharmacy attained its highest reputation and became an independent branch of medicine. It is interesting to note that the first dispensary was opened in Baghdad, the center of trade. The dispensary was made of Sandal wood and named "Sandalia". Rhazey (850-932 A.C.) who was born at Rai in Persia was the director of Baghdad hospital in the days of El-Mansour. He published a famous book "Alhawi Kabeer". Ibn Al-Baitar (1197-1248 A.C.) was the best Arabian pharmacognosist and botanist and ranked with Dioscorides in that respect. His book "Jame-ul-Muffradat" contains description of 2000 drugs. Sheikh Dawood El-Antaki wrote a book named "Tazkaret Uli Al-Albab", now known as "Tazkaret Dawood Alantaki" which describes several hundred herbs, animal and mineral drugs.  Crude Drugs It means the harvested and usually dried plant or animal sources of pharmaceutically or medicinally useful products before they have undergone extensive processing or modification. Crude drugs of vegetable, animal and mineral origin form the subject matter with which pharmacognosy is concerned. Formerly crude drugs were termed "Simple Drugs" indicating that they exist as they occur naturally; not having been compounded or mixed with other substances.  Examples of crude drugs Entire plants or animals: Mentha, Lobelia, Cantharidis, Thyme, Colocynth. Entire organs of plants or animals: Senna, Clove, Fennel, Linseed, Cinchona, Liquorice, Thyroid gland. Minerals: chalk, kaolin, talc. Other categories of substances include: Includes surgical dressing fibers and fabrics. Substances: Agar, gelatin, wax. Insecticides and pesticides: derris and pyrethrum. Classification of crude drugs Vegetable drugs are usually arranged for study in one or other of the following ways: a- Alphabetical classification: Using either Latin or English names. The drugs are arranged in an alphabetical order. b- Taxonomic classification: Using one of the accepted systems of botanical classification. The drugs are arranged according to the plants from which they are obtained in phyla, orders, families, genera and species. Phylum : Spermatophyta Division: Angiospermae Class : Dicotyledons Order: Rosales Family: Leguminosae (Fabaceae) Sub-family: Papilionaceae Genus: Glycyrrhiza Species: Glycyrrhiza glabra c- Morphological classification: In this system the organized drugs are arranged according to the morphological similarities and dissimilarities of various plant parts which constitute the drugs. Organized drugs: These are drugs derived from distinct and complete parts of plants. e.g. leaves, flowers, fruits, seeds, herbs, roots and rhizomes, barks, woods. Unorganized drugs: These are excreted or natural substances that do not show any distinct cellular structure. Groups as dried lattices, extracts, gums, resins, oil, fats and waxes. Examples of Morphological classification  Seed Nux vomica  Leaves Senna  Barks Cinchona  Dried latex Opium  Gum Acacia d- Chemical classification: The drugs are divided into groups according to their most important constituents e.g. Drugs containing volatile oils, glycosides, alkaloids, bitter principles, tannin, saponins, etc. e- Pharmacological classification: A classification involving the grouping of drugs according to the pharmacological action of their most important constituents or their therapeutic use. B. Drugs acting on respiratory system Expectorants Liquorice Antitussive Opium (codeine) Bronchodilators Ephedra C. Drugs acting on cardio-vascular system Cardiotonic Digitalis Cardiac depressants Chichona Antihypertensive Rauwolfia D. Drugs acting on autonomic nervous system Adrenergics Ephedra Cholinergics Physostigma Anticholinergics Belladona Official and unofficial drugs An official drug is one which is listed and described in a book recognized by the government as the legal authority for standards "Pharmacopoeia“. Unofficial drugs: These are drugs not listed in any recognized pharmacopoeia. They may still be used in practice but are not governed by the same official standards for quality and purity. The pharmacopoeia sets the standards for the purity, strength, and quality of the drug. The first Egyptian pharmacopoeia appeared in English in 1953, and in Arabic in 1961. The Egyptian Pharmacopoea 1984 gives the name of drugs in Latin, English, Arabic, as well as the German, French and Italian names, sometimes other synonyms are given also. Description of each individual drug 1.Origin: including biological and geographical sources, a knowledge of the history and name of the drug. 2.Cultivation and preparation: including details of cultivation of the medicinal plants, methods of collection, drying, packing and other treatment of the drug during its preparation for the market. 3.Characters: including the physical characters such as dimensions, surface characters, fracture and the sensory characters such as colour, odour and taste. The histological characters which help in the identification of the drug in powdered form, are of fundamental importance. 4. Constituents and tests: constituents include both the reputed active constituents and also other constituents and reserve food materials. Chemical identity tests are based on the nature of constituents 5. Adulterants: including materials added fraudulently and matter which has become associated with the drug owing to carelessness in handling during collection, preparation, packing and transport. 6. Evaluation of the physical and chemical characters of the drug. 7. Uses and application of the drug in medicine.  Origin of drugs There are two origins for each drug; the natural or biological, as well as, the geographical origin. The commercial origin is also of interest in case of certain drugs. Once the remedial value of a drug is established, the pharmacognosist is in the first place interested to find out the biological and geographical origin of this drug. 1.The natural or biological origin (source( The natural origin of a drug is the plant or animal yielding it, if a plant, botanical origin or botanical source and if an animal, zoological origin or source. Despite the increasing importance of animals in providing sources of medicinally and pharmaceutically important products, the majority of drugs of biological origin still are obtained from plants.  The binomial system Is due to Swedish biologist Linnaus. In this system, the first name, which is always spelt with capital letter, denotes the genus. The second name denotes the species. However, still correct to use capital where the species is named after a person. Thus the species of Cinchona named after Charles Ledger, who brought its seed from Brazil 1865, is known as Cinchona Ledgeriana. The specific name is usually chosen to indicate: 1- Some striking characteristics of the plant: a- Conium maculatum (maculate = spotted) (stem with reddish, spotted patches). b- Glycyrrhiza glabra (glabrous = smooth). Refers to the fruit of this species which is a smooth pod. c- Hyoscyamus muticus (muticus = short). The plant being short. d- Atropa belladonna (bella = beautiful, donna = lady). The juice of the berry placed in the eyes causes dilatation of the pupils, thus giving a striking appearance. 2- A characteristic colour: a- Piper nigrum (= black) b- Veratrum viride (= green) c- Citrus aurantium (= golden yellow) d- Digitalis purpurea (= purple) e- Digitalis lutea (= yellow) 3- An aromatic plant or certain aroma: a- Myristica fragrans (having a fragrant, nice aroma) b- Caryophyllus aromaticus (refers to the aroma) 4- A geographical source or history of a drug: a- Cannabis indica (growing in India) b- Tamarinds indica (India) c- Olea arabica (Arabia) d- Balanites aegyptiaca (Egypt) 5- A Pharmaceutical activity or active constituents: a- Papaver somniferum (sleep inducing) b- Strychnos nux vomica (from two latin words, nut causing vomiting) c- Ipomoea purga (laxative). d- Quillaja saponaria (contains saponins) 6- A general meaning or a special indication a- Allium sativum (= cultivated) b- Triticum vulgaire (= wild) 7- The generic name may also allude to certain characters of the plant: a- Atropa, from Atrops, meaning flexile, the name of the Greek fate who cuts the thread of life, alluding to the poisonous characters of the drugs. b- Glycyrrhiza is from glucose= sweet, riza = root.  2. Geographical sources of drugs The geographical source or habitat refers to the region where the plant or animal producing the drug grows. Plants growing in their native countries are said to be indigenous to these regions, e.g.:  Aconitum napellus of the mountainous regions of Europe. Hyoscyamus muticus of Egypt. Cannabis sativa of India. Every climatic region on Earth, from Antarctica to the Arctic, is the native habitat of some species of animals and plants. The tropics and subtropics yield more drugs than the arctic and Antarctic regions. The Mediterranean region, including Turkey, yields more drugs than any region. India, the East Indies, Central Europe, Northern South America, and central America are the main sources of valuable drugs.  Exotic plants, not of native origin, are considered naturalized plants. Studying the habitat ‫ موطن‬helps in determining the soil, climatic conditions, and altitude of the plant. For example,  Cannabis sativa, native to India, produces weak fibers and resin, but produces strong, economic-value fibers when grown in Italy.  Cinchona calisaya ‫الكينا‬, native to Brazil and grows at high altitude and warm moist conditions resulted in plants with high % of A.C. In India, soil is similar to Brazil, but not the same altitude resulted in plants with low % of A.C.  Datura sauveolens growing in Brazil contain mainly hyoscyamine and traces of hyoscine. When introduced in Egypt, it was found to contain hyoscine and mateloidine; in addition to traces of hyoscyamine. Production of Crude Drugs Production of crude drugs from their medicinal plants involves the following steps: I. Cultivation II. Collection III. Drying IV. Packing V. Preservation and protection I. Cultivation of medicinal plants Crude medicinal drugs may be collected from: Wild growing or Cultivated medicinal plants. Plants growing in their native countries are said to be indigenous to these regions, e.g. Aconitum napellus of the mountainous regions of Europe, Hyoscyamus muticus of Egypt, Cannabis sativa of India. Plants are said to be naturalized when they grow in a foreign land or in locality other than their native home. Collection of Crude drugs from wild growing medicinal plants has the following disadvantages: 1- Wild plants are found in "sparse distribution" over unlimited areas and are not confined to a limited space. 2- There is significant difficulty in collection and transportation because they are mostly growing in deserts and forests far from any means of transport. 3- Ruthless collection “Continuous extensive collection” of wild medicinal plants can lead to extinction or serious deficiency of the plant. 4- The collected amount of wild medicinal plants may be insufficient for the market needs. 5- Collection of crude medicinal drugs from wild sources may lead to adulteration that can be attributed to ignorance of collectors who may collect: a- The desired plant with others. b- Undesirable organ of the desired plant. c- The desired plant at improper time. Collection of Crude drugs from cultivated growing medicinal plants has the following advantages 1- Concentration of a large quantity of the plant of choice in relatively small areas simplifies collection. 2- Cultivation provides an excellent mean for control of the purity of the crude drug. 3- Cultivation assures regular and constant supply can be sufficient to market needs. 4- Cultivation allows producers to apply different methods for improvement of the gained crude drug by controlling certain factors: a- Treatment of seeds before sowing to ensure germination and exclusion of defective seeds i.e. soaking Hyoscyamus seeds in dilute sulphuric acid fasten germination. b- The use of fertilizers which can provide cultivated plants with certain essential elements as N, K and P which can increase the produced active constituents. c- The use of certain insecticides and pesticides help control of insect’s infestations. The disadvantages of collection of crude drugs from cultivated medicinal plants are: 1- The high cost of production when applied on small scale while economic only when carried on large scale. 2- Some medicinal plants require particular habitat for their growth and the procedures of their cultivation usually gain failure. i.e. Cannabis requires tropical climate production of narcotic resin while Aloes require a heavy rainfall. Medicinal plants and environment For the success of cultivation of medicinal plants and production of crude drugs with quality, it is necessary to study the conditions under which medicinal plants flourish in their wild state and trying improve them. a- Water: 1- It is an important component of the cell which is the building unit for every living creature. 2- It is a vital factor in all biological reactions and transformations in living beings, it can act as medium, catalyst, part of the biological reaction or even end product of it. Rainfall patterns, including the amount and timing, significantly affect plant growth. The efficiency of water use depends on balancing water intake with losses from transpiration and soil evaporation, shaping the vegetation in different regions. b- Temperature: Temperature divides the world into various zones and plant growth is greatly affected by temperature. It has a great effect on seeding i.e as temperature is increased, the rate of growth is increases until an optimum value is reached, above which further increase in temperature leads to a decrease in growth rate. This is due to the fact that chemical reactions, in general, increase in rate as temperature is increased, but as it is still further increased, other reactions, such as heat denaturation and protein inactivation predominates. For each plant, growth is designated by three temperatures: - The minimum temperature - The optimum temperature - The maximum temperature Diurnal temperature cycle: The day temps. are higher than the night temp. These diurnal changes are important in their influence on plant growth. The optimum day temp. for growth and development of many plants are higher than the optimum night temperature. Plant growth is therefore greater in an appropriately fluctuating temp. than in any single constant one. Thermoperiodicity: the relation of temp. to plant growth. Temperate plants: (grow naturally in places where the weather is neither very hot nor very cold, where diurnal temp. fluctuations are a characteristic feature of climate) Exhibit best growth in fluctuating temperature. c- Altitude: It affects the growth of medicinal plants. Coconut palms and sugar cane require maritime lowland climates ‫بحري‬ Tea, Cacao, Coffee, medicinal Rhubarb, Tragacanth, and Cinchona require elevation. In general, the highest temperature are experienced near the equator, and temperature falls with elevation. i.e Jamaica to have a tropical climate on the coast and a temperate one in the mountains so sugar can be cultivated at the coast as it is a lowland plant while Tea can be cultivated at elevations. d- Light: Plants vary in the amount and intensity of the light which they require. The effects of light intensities on the growth of plants are related mainly to the role of light in “Photosynthesis”. ‘Photoperiodism’: defined as the response of plants to the length of day, or correctly, to the relative length of day and night. Plants classified into three broad photoperiodic classes with respect to their flowering behavior: 1- Short-day plants: These plants flower only when the daily period of illumination is shorter than a particular critical length i.e. Tobacco. 2- Long-day plants: These plants flower only when the daily period of illumination exceeds some critical duration i.e. Spinach. 3- Day-neutral plants: These plants flower under any of a wide range of day lengths i.e. Capsicum. e. Soil Soil is a mosaic of rock particles, plant roots, micro- organisms, decaying organic matter (humus), aqueous soil solution and interconnecting air passages. Soil is a store house of water and minerals required for growth of plants. Soil differs from one another both in physical and chemical properties. "Pharmacists don't just dispense medication, dispense hope and care. Keep pushing forward!"