Lecture 2: Source of Medicinal Plants PDF

Source of the medicinal plants may be: 1. Collection ( from wild plants ) 2. Cultivation (commercial),[ collection, harvesting, drying, garbling, packaging, storage and preservation e.g. ginseng, ginkgo, peppermint] 3. Fermentation (Recombinant DNA technology or Genetically engineer...

Source of the medicinal plants may be: 1. Collection ( from wild plants ) 2. Cultivation (commercial),[ collection, harvesting, drying, garbling, packaging, storage and preservation e.g. ginseng, ginkgo, peppermint] 3. Fermentation (Recombinant DNA technology or Genetically engineered drugs 4. Cell-culture techniques 5. Microbial transformation  1-Cultivation 2- Collection 3-Preparation of drug before drying Preparation of drugs 4- Drying 5- Packing 6-Storage 1- Cultivation  Medicinal Plants A- wild B- cultivated 1-Concentration 4-Improvement in a small of the drug and 1- Distribution in 4- Collection by the plants controlled area unlimited area untrained persons 5-Control of purity 2-Direct and prevention of transportation admixture 2- Difficulty 5-Eradication in transport 6-The presence of flora 3- Continuous of trained 3- Insufficiency of supply of drug workers supply for market demands  Factors Affecting Plant Growth 1- Environmental 3- Growth regulators. factors: water, light, Temp, & altitude 4- Genetics and plant 2- Soil and soil contents tissue culture. C. Growth regulators: Four groups of plant hormones or growth regulators were established; Auxins (3-indol acetic acid) affects cell elongation, resulting in an increase in stem length and inhibit root growth. Gibberellins induce flowering plant at earlier stages and increase plant height. Also, it increases the active constituents of many plants. Cytokinins (Abscisic acid and ethylene), they are called cell division hormones. Moreover, they regulate pattern and frequency of organ production.  2- Collection Proper collection is very important to obtain a drug of good quality.  All parts of the plant or The active Concentrated in certain constituents organ or may be In specific tissues of this distributed in organ. Time of the year. Factors affecting Time of the day. collection Stage of maturity.  A) Time of the year The amount and the nature of the active constituents is not constant through the year 1- Rhubarb contains 2- Colchicum corms have anthranols (active no alkaloids (containing metabolites) in winter and starch) in autumn but anthraquinones (pro-drug) rich in alkaloid in spring. in summer  B) Time of the day The amount and composition of a number of constituents may vary throughout the day and night. ❑1- Digitalis leaves ❑ 2- Solanaceous leaves collected in the have higher alkaloid afternoon contain more content in the morning cardiac glycosides than than those collected in the those collected in the afternoon. morning.  C) Stage of maturity Age of the plant The age of the plant governs not only the total quantity, but also relative proportion of the active constituents. 1-Cloves collected 2- All solanaceous as flower buds with leaves contain higher the highest percentage alkaloid content when the plant is in the of volatile oil. flowering stage.  General rules for the collection of drug organs To ensure maximum quality of a crude drug, it must be collected at a proper stage of development. Leaves, flowers and fruits should be collected in dry weather. 1-Collection of leaves at the beginning of the flowering stage in dry Wet weather may cause deterioration weather and discoloration during drying. Tea leaves: The best quality are collected when still in the bud. 2-Collection of flowers 1-in dry weather in order to fix the color of the product. 2-just at the time of pollination and before the formation of fruits.  Clove collected in bud stage Exceptions are Chamomile flower collected just after full expansion.  3-Collection of fruits ❑Near the ripening season, when they are full mature but not completely ripened (i.e. before ripening). Senna pods  4-Collection of barks ❑Usually done in spring or in early summer (why?) 1-Cambium is active 2-The bark can be easily stripped off from the trunk and branches (after rainy season).  5-Collection of the seeds The Seeds are collected when mature and ripe. Linseed  6-Collection of underground organs (Roots, Rhizome, Bulbs and Corms) Generally they should be collected in autumn or winter After removal of aerial parts  7-Collection of unorganized drugs (resins, gums, latex,…) ❑They are usually Collected in dry weather to prevent stickiness and darkening in colour 3-Preparation of drug before drying 1-Cleaning Washing, cut into slices, decortication 2- Garbling 3-Preparation 3-Bleaching of drug before drying 4- Curing 5-Decortication  Cleaning of the collected plants A-Underground organs should be freed from soil by shaking, brushing or washing under stream of water B-Any diseased part, or attacked by insects should be rejected. C-All large organs ( roots or rhizomes) should be sliced to facilitate drying. D-The stalks are removed from leaves and fruits  3-Preparation of drugs before drying Curing of drugs Decortication Bleaching  Removal of the Decortication:- outer layers ( cork and cortex) Why? a- Lack or low percentage of active principles in the outer parts. b- Presence of unrequired constituents in the outer tissues. e.g. cinnamon  Alters the appearance of certain drugs when Bleaching:- they are being prepared for the market and prevent insect attack.e.g. red algae & ginger The red algae exposure to “Carrageen” appears sunlight in commerce as a pale cream colored drug. coating with a layer Ginger of inert substance such as CaCO3 or CaSO4  Inducing some desirable changes in the drug after collection and before Curing :- drying by enzymatic action. A- Tea leaves:- 1-To set free soluble caffeine 2- to oxidize tannin into insoluble products.. 2- Vanilla pods:- To set free vanillin (aromatic odour)  Vanilla pods Curing Oxidizing and hydrolysing enzymes Before curing After curing 1- Change in color 2- Change in odor ( free vanillin) 4-Drying of crude drug Removal of water or most of it from the fresh living tissues (up to 80%). 4- Careful drying is essential retain physical Drying characters and chemical constituents of of drug, and comply the pharmacopoeia crude requirements for maximum moisture drug contents. The duration of drying process varies from (few hour) to (many weeks)  Stops enzymatic action that might change the active constituents. Avoids deterioration upon storage by preventing the growth of microorganisms (bacteria and fungi). Why Drying is Facilitates grinding into powdered form. necessary? Reduces weight and bulk facilitates packing and storage.  The most important factors in drying process 1- Temperature 2- Time ❑ To use as low ❑ To carry out the temperature as operation as rapid as possible. possible.