Medicinal Plants Lecture No. 8 PDF

Medicinal Plants Lecture no. 8  Reserved Food Materials (Primary metabolites) Fixed Oil, Fat Carbohydrates Protein and Waxes  Plant Cell Content Reserve...

Medicinal Plants Lecture no. 8  Reserved Food Materials (Primary metabolites) Fixed Oil, Fat Carbohydrates Protein and Waxes  Plant Cell Content Reserved Food Material  Inulin It replaces starch as the reserved carbohydrate in the subterranean organs as in plants of family: Compositae. It consists of β-D-1,2 furanofructose. It is hydrolysed by acids to D-fructose, but not hydrolyzed by amylase enzyme. Properties: It is white powder, slightly soluble in cold water, does not give colour with iodine. ▪ Uses: It is used in culture media as fermentative identifying agent for certain bacteria.  Cellulose (Plant Structural Material) - The main constituent of the cell walls of plants. Structure: - It is a linear β- 1, 4 polymer of glucose (containing 300-25,000 residues). - Since our glycosidases are unable to hydrolyze the beta linkages in cellulose, we cannot digest cellulose. - Its complete hydrolysis by conc. mineral acids (HCl or H2SO4 or HNO3) yields β -D- glucose units. Uses: Employed as surgical dressing.  Mucilage Complex polysaccharides that occur as white amorphous mass, found in the cortical cells of the roots, rhizomes and in the leaves, the endosperm of seeds. It forms a viscous colloidal solution without adhesive properties. It is classified to three types: 1- Neutral mucilage: Consists of D-mannose units (85%) and D galactose units (15%). 2- Acidic mucilage: It contain uronic acid residues mainly galactouronic acid, while the most sugars occuring in this type are D-galactose, xylose, arabinose and rhamnose. 3- Seaweed mucilage: They are sulphate esters of polysaccharides. A: Linseed (Flaxseed), B: Fenugreek, C: Okra, D: Aloe and E: Corchorus  Uses: 1 Demulcent 2 Cathartic (purgative), (ability to swell, lead to bulk formation and lubrication) in constipation. 3 Antidiabetic 4 Prevention from colon cancer Chemical test: 1- Acidic mucilage: gives red color with Ruthenium red reagent (Linseed) 2- Neutral mucilage: gives blue color with Methylene blue reagent (Foenugreek)  Pectin It is produced during ripening of Citrus fruits It disperses in water to a viscous colloidal solution without adhesive properties. Uses: It is classified as a protective agent: having the property of conjugating with toxins and absorbing them, so it is used in treatment of intestinal disorders as diarrhoea and dysentry. In pharmacy as a gel and emulsion stabilizer. Slimming agent (Applelite© Tablet) Preparation of jellies.  Gum Natural gums are polysaccharides of natural origin, capable of causing a large increase in a solution’s viscosity, even at small concentrations. They are used in food industry as thickening agents, gelling agents, emulsifying agents and stabilizers. In other industries, they are also used as adhesives and binding agents. It forms viscous colloidal solution with adhesive properties. Most often these gums are found in the woody elements of plants or in seed coatings. They are produced in higher plants as protective after injury (pathological). e.g. Gum acacia, Gum tragacanth.  Chitin It is a nitogenous polysaccharide present in certain shrimps and certain fungi. It is insoluble in water, alcohol, but soluble in strong mineral acids. It is hydrolysed by strong acids to glucosamine (oesteoarthritis) and acetic acid. It gives with iodine-potassium iodide solution a brown colour. It is formed of units of N-acetyl-D-glucosamine linked by 1,4-β- glycosidic bond. Chitin sources shrimps and insects.  II- Protein Nitrogenous organic reserved food materials of essential nutritive value. Proteins are nitrogenous organic substances which give on hydrolysis polypeptides, dipeptides then amino acids. They are present in all living cells and stored by plants usually in the form of amorphous masses or small particles called aleurone grains. Aleurone grains are larger in size in oily cells than those in starchy cells  The simplest aleurone grain consists of a mass of protein surrounded by a thin membrane The ground mass of protein encloses one or more rounded bodies known as globoid and an angular body known as crystalloid Aleurone grains are best observed after defatting and removal of starch Globoid Amorphous protein Crystalloid protein Aleurone grain Eg Linseed  Characters All proteins are insoluble in organic solvents. They are generally precipitated or coagulated by heat, by marking change in pH or by high salt concentrations. ❖ Chemical tests (microscopically) 1- Red color or precipitate with Millon’s reagent 2- Picric acid solution 1% stains the crystalloid and ground substance only yellow, leaving globoid unstained.  III-Fixed oils, Fats and Waxes ▪ Reserved food materials occurring in various parts of the plants and animals. ▪ Mixture of esters of fatty acids with glycerols (glycerides or glyceryl esters). ▪ Greasy, non volatile, viscous, liquids (oils), semisolid (fats) or solid (waxes). ▪ Insoluble in water or cold alcohol, soluble in ether, chloroform, petroleum ether and benzene. ▪ They are hydrolyzed by aqueous alkalis giving soap (salt of fatty acids). ▪ Permanent stain on paper Fixed oils are classified according to their ability to absorb oxygen and to form hard film into: ❑ Drying oils as Linseed oil. ❑ Semi-drying oils as Sesame oil. ❑ Non-drying oils as Olive oil.