ECU Preparation of Drugs from Plants to Pharmaceuticals PDF

Faculty of Pharmacy and Drug Technology Preparation of Drugs from Plants to Pharmaceuticals VI-Collection & Drying of Aromatic and Medicinal Plants Story of a medicinal plant from cultivation to pharmaceutical product Example: Tea...

Faculty of Pharmacy and Drug Technology Preparation of Drugs from Plants to Pharmaceuticals VI-Collection & Drying of Aromatic and Medicinal Plants Story of a medicinal plant from cultivation to pharmaceutical product Example: Tea grinding Tea plant collection Drying Crude drug farming Aim: obtain a high yield of active consituents. Isolation of caffeine Caffeine crystals A-Collection of Medicinal Plants The drug should be collected when it contains the largest amount of active constituents. Collection of plants is controlled by many factors I-Part or organ of the plant II- Effect of time III- Stage of maturity I-part or organ of the plant Part of the plant to be collected which contains the maximum amount of A.C. (medicinal part used) II- Effect of time: An active constituent may be present in summer but absent in winter, not only the time of the year but also the time of the day 1- Time of the year Colchicum corm: Collected in spring and early summer to obtain high percent of active constituents (colchicine). If collected in Autumn or winter it contains only starch and used instead of potatoes as food in Austria. Winter Summer ------------- Bitter taste (Colchicine) High content of Low content of starch starch 2- Time of the day - Volatile oil containing plants are collected in morning because the % of oil decrease by day by action of heat. -Solanaceous leaves are collected in early morning as the alkaloids are synthesized allover the night. III- Stage of maturity: - Clove is collected in the bud form. - III- Stage of maturity and age: - Solanaceous leaves at the flowering stage, by fruiting the alkaloids decrease. General rules for collecting medicinal plants: Leaves: fully mature in the flowering stage, except : Tea: bud form. Coca: older leaves. Uva ursi: at any time of the year. Flowers: before the full expansion. Stem barks: in spring when it can be stripped. Fruits: fully mature but unripe. Seeds: mature.  Preparation of medicinal plants: Cleaning: underground organs should be freed from soil by brushing or washing (peeling, slicing and bleaching). Garbling: the removal of extraneous matter such as sand or other parts of the plant and classification into grades.  B-Drying of Crude Plants Plants may be used fresh or Dried.  Objectives of Drying of Plants 1-To decrease size and weight of the plant. This facilitates packing, transport and storage. 2-To aid their preservation (prevent growth of microorganisms). 3-To facilitate powdering of the plant. 4-To stop enzymatic action which may destroy active constituents. 5-Concentration of the active constituents. There are two main important factors in drying ❑Temperature: It shouldn’t be too high to prevent A.C. destruction. Optimum temp., duration of temp. differ from plant & organ to another. Some drugs have specified degree of temp. e.g. Digitalis ❑Moisture: Should be reduced to minimum  Methods of drying Natural drying Artificial drying 1. Sun 2. Shade Chemical Elevated and Lyophilization drying controlled Temperature Drying chamber Oven Vacuum oven tunnel dryer pneumatic high speed drying Suitable for heat-sensitive constituents Suitable for heat-stable constituents. Methods of drying: I- Natural drying 1- Sun drying: -Plants spread in single layer, and as drying proceeds are turned over and then covered at night. -Shelves which are shaded must be used when the sun is powerful.  Disadvantages: It may affect the colour, odour, active constituents of medicinal plants. Time consuming (4-7 days). 2-Shade drying: This process is cheap and takes long time, but used to avoid these disadvantages. II-Artificial drying it is much more superior than the natural, why? Because: 1. Rapid (prevent decomposition of active principles and retain color of the plant). 2. Could be done under controlled temperature. 3. We can immediately stop enzymatic activity at temp. (55-70oC) May be physical (heat, freezing or radiation) or chemical (using desiccants). Artificial drying is classified into: 1. Under controlled temp. (drying chamber-ovens-vacuum ovens- tunnel dryer). 2. Freeze drying (Lyophilization). 3. Chemical drying (using dessicators with CaCl2, H2SO4 or silica gel). Methods of artificial drying: 1- Drying sheds or chambers It is a small chamber provided with - Shelves that carry perforated trays that carry the plants. -Suitable door. -Window to detect the end of drying. -Heater near the roof which heat the air pushed by a fan. -Thermometer and thermostat. -Hot air passes over the drug and moist air exits near the floor. 2. Drying oven: It is a small cabinet having a source of heat, device for circulatory air, thermostat and a thermometer. Air is heated and come in contact with plants on shelves & moist air comes out from another upper opening. Has lower capacity than the chamber. 3. Vacuum Oven: Sometimes it is evacuated (vacuum). Heating and evacuation are done at the same time (water boils at 40⁰C) thus help rapid evaporation & A.C. are unaffected e.g. cardiac glycosides containing plants, e.g. Digitalis. 4. Tunnel dryer: The plant is put in moving trucks upon which hot air is passed and comes out dry drug. 5. Pneumatic high-speed drying: Drying is done by exposure to high temp. (300-800⁰C) for a fraction of second under reduced pressure. For sensitive drugs e.g. Digitalis. 6- Lyophilization (freeze drying): It is used for biological fluids (hormones, enzymes and blood plasma) and royal gel. It is a form of vacuum drying. The plant is subjected to -10 to -20⁰C so water is converted into ice and then the vacuum is used so the ice is sublimed and the drug becomes free from water. B- Chemical method of drying: The plant is subjected to dry atmosphere by placing it in a dessicator with a dehydrating agent (with CaCl2, H2SO4 or Silica gel) and left to dry. Small scale Changes in drugs during Drying: Changes in drugs during Drying: ❑Size and weight (80-90% is reduced). ❑Shape and appearance. Black pepper shows polygonal reticulations. The inner surface of most barks shows depressed dark appearance ❑Texture (may be hard, brittle, horny…….etc.) ❑Colour e.g. tea and vanilla. ❑Odour e.g. vanilla and Digitalis leaves. ❑Taste e.g. Gentian (becomes sweeter due to the separation of gentiotriose sugar). ❑Active Constituents (glucovanillin to vanillin).  C-Packing of Drugs To reduce space- for protection-easy transport- easy storage. Packing forms depend on the nature of active constituents Cardiac glycosides of Digitalis: packed in tins with sealed tops and may be kept in sealed ampoules. Volatile oil containing drugs: packed in sealed tins or cans. Volatile oils: are kept in enameled containers or amber-colored glass. Cheap plants: e.g.Hyoscyamus which are unaffected by conditions are kept in sacks.  Adulteration of herbal drugs ❑ Could be intentional or accidental. Occur frequently to expensive and rare herbs Sophistication (True Substitution Admixture Adulteration) Intentional / deliberate / Unintentional / unknowing Unintentional / unknowing / knowing / accidental accidental Adulterated ginger : Completely different Collecting karkadeh leaves in Ginger + starch + curcuma herbal material addition to flowers (wrong (color) + capsicum (taste) Xanthium ---- Stramonium part) Clove stalk ---- Clove Collecting colchicum at early buds autumn (wrong time) Contain Genuine + diluents Contain No Genuine contain Genuine + other material at all material Clove buds Stramonium xanthium Clove stalk  Other types of adulteration ❑ Selling herbal material of inferior quality, e.g., has a lower content of A.C. than the value specified in Pharmacopiea, tea of low caffeine content. ❑ Selling exhausted herbal material (Exhausted: removal of A.C.) for example: extracting tea or karakadeh, drying of remaining herbal material, reselling. ❑ Selling deteriorated (rancid olive oil) or spoiled herbal material (contaminated with fungal or bacterial material) Common worthless material used in adulteration: (Saw dust, olive or date stones, almond or coconut shells, starches, sand) Detection by macro- and microscopical examination, organoleptic, physical and chemical analysis  Primary metabolites e.g. Starch, lipids, protein Water - Essential for living of the plant supply Used for growth and storage - light present in all plant cells - Photosynthesis - Important for basic human nutrition Biosynthesis Soil Amino acids, Sugars, Secondary metabolites nutrients e.g. Aroma, colorants, Fatty acids - Not essntial for living of the plant, however, important for adaption to the environment.e.g. Attraction of insects, birds for seeds dispersal and pollination. Factors affect the growth and Defending against bacteria, fungi, health of medicinal plants will and animals - Not present in all plant cells in turn affect the yield of its - Important for healthy human active constituents. nutrition or important as a medicine  V-Factors affecting plant growth and production of drugs I-External (extrinsic) factors: a. Environmental factors e.g. water, light, temperature, altitude, etc. b. Soil and its content. II-Internal (intrinsic) factors: Growth regulators: Hormones.  B- Soil and soil contents: It is a mixture of mineral particles, organic matter (humus), living micro-organisms and aqueous solution. Soils are classified according to particle size into Clay (high power of absorbing water) and Sandy soil (low absolute water capacity)---- etc. According to humus content, the soil is described as poor, intermediate , rich or vegetable soil. Humus (Manures) (Plant nutrient) it is obtained from: 1-Remains of humans and animals. 2-Green crops. 3- Ashes of burned bones and birds having containing minerals. It is a mixture of organic matter (plant put under animal, mixed with animal urine, excretions and some soil). Organic farming  It includes the following elements: A. Main elements (macronutrients) [very important and essential to the plant, excess do not kill the plant] e.g. nitrogen, phosphorus, potassium simple fertilizers have one of them, complete fertilizers have all of them B. Microelements: essential in low concentrations, excess is harmful for the plant. e.g. Cu, Zn, Fe C. Active elements required in small amounts, excess is not harmful. e.g. calcium, magnesium, sulphur D. Inactive elements needed by a number of plants e.g. sodium, aluminium, silicon and I2  B-Intrinsic factors affecting growth (Hormones) Hormones are chemical substances produced by certain tissues that control growth and metabolism of the living organism. It is secreted in little amounts and responsible for: 1. Cell division. 2. Cell differentiation. 3. Cell growth. 4. Development 5. Damage healing. 6. Dormancy. 7. Bud growth. 8. Aging. 9. Defense These include: I. Growth stimulators (1)Auxins. (2)Gibberellins. (3)Cytokinines. II. Inhibitors: (1)Abscisic acid. (2)Ethylene oxide Hormone Main action Auxin Cell elongation and expansion. Root and shoot formation. auxein - "to Phototropy and gravitotropy. grow/increase" Cytokinin Cell division and cell growth. Used by farmers to increase crops Cyto: cell Root and stem morphogenesis kinin Its function is opposite to auxins Gibberillic Break seed dormancy; Initiate synthesis of enzymes, especially acid hydrolytic enzymes which hydrolyze carbohydrates & proteins to provide the plant with simple sugar & simple amino acids. So it is responsible for seed germination Abscisic acid (opposite to gibberillic acid) Leaf abscission and promote seed dormancy. Ethylene Discovered in stored apples and help in: oxide Inhibition of potato shoots growth  Plant hormones Site of action and hormone level affect the function of hormone e.g. auxins in root (gravitotropy), while in shoot (phototropy) Actions of plant hormones complement each others, although some have opposing function. The final outcome depend on the relative level of the hormones cytokinines + auxins shoot Cytokinines + auxins root