Medical Plant Section 1 PDF

Pharmacognosy Pharmacognosy : Is the study of medicines derived from natural sources. The American Society of Pharmacognosy defines pharmacognosy as "the study of the physical, chemical, biochemical and biological properties of drugs, drug substances or potential drugs or drug substances of natural o...

Pharmacognosy Pharmacognosy : Is the study of medicines derived from natural sources. The American Society of Pharmacognosy defines pharmacognosy as "the 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. It is also defined as the study of crude drugs.  Origin Latin name of plant & origin: Genus (start with capital and italic) + species (start with small and italic) + Family (start with capital) Example: Datura stramonum or Datura stramonum Family.Solanaceae  Reserved food material 1) starch It is the principle food reserve of plants. When there is more glucose present in the organism than is needed , at the moment , starch is deposited in the plant cell. Starch is most abundant in storage organs as seeds , fruits, root, stems.  Structure of starch: It consists of number of α-D glucose units. It consists of two structurally different polysaccharides one linear (amylose) and the other branched (amylopectin). Hydrolysis of starch involves the cleavage of 1,4- glycosidic bond and production of many molecules of glucose. This is done by enzyme called glycosidases( β- amylase).  Uses of starch : 1) Nutrient. 2) Diluents or disintegrant. 3) Antidote for iodine poisoning. 4) Starting material or precursor for -Liquid glucose. - Dextrose. -Dextrin. -Maltose.  Physical characters : 1) Conditin : powder 2) colour: white. 3) Odour : odourless. 4) slubility: insoluble in water 5)Homogenity : homogenous. 6) Touch : smooth ( Rice :gritty). 7) Taste : starchy. 8) Reaction with litmus paper: neutral. Chemical characters:(for all types of starch) 1) Effect of iodine :blue color. 2) Effect of H2SO4: charring. 3) Effect of hot H2O:gelatinization forming gel like on cooling.  Types of starch 1)potato starch origin : It is a polysaccharide granules formed from tubers called Solanum tuberosum F. Solanaceae.  Microscopical characters: 1)Shape : ovate. 2) Size : large. 3) Hilum : present ( distinct) , eccentric point. 4) Striations : present( distinct) , concentric. 5) Aggregation : mainly simple ( sometimes compound or semicompound).  2)Wheat starch Origin : It is a polysaccharide granules obtained from grains of Triticum vulgaris F. Gramineae.  Microscopical characters: 1) Shape : rounded or lenticular. 2) Size : medium. 3) Hilum : present (faint) , centric point. 4) striations: present (faint) , concentric. Aggregation : mainly simple. (5  3)Maize starch: Origin : It is a polysaccharides granules obtained from grains of Zea mays F. Gramineae.  Microscopical characters: 1) Shape : polyhedral. 2) Size : medium. 3) Hilum : present(distinct) , centric , cleft (x- shape ,y-shape) 4) Striations : invisible or absent. 5) Aggregation : mainly simple.  4) Rice starch : Origin : It ispolysaccharides granules obtained from grains of Oriza sativa F. Gramineae.  Microscopical characters: 1) Shape : polyhedral. 2) Size : small. 3) Hilum : invisible or absent. Striations : invisible or absent.(4 5) Aggregation : mainly compound (contain more than two granules without acommon sheath).