Medicinal Plants PGC 101 First year Students Prelab1

Medicinal Plants (PGC 101) First year Students Prelab-1 Pharmacognosy Department

Material needed in lab 1 - Lab coat 2 - Practical note 3 - Pencil (HB, 0. 5 mm) 4 - Slides 5 - Covers 6 - Watch glass 7 - Glover’s needle 8 - Forceps 9 - ﻓﻮﻃﺔ ﺻﻔﺮﺍﺀ

Dusting Powders (Fine powders) Starches Non- Starches 1 -Potato Starch 2 -Wheat Starch 3 -Maize Starch 4 -Rice Starch - It is the principal reserve food material of plants, stored in seeds, fruits , tubers and roots. - It is the first product of photosynthesis.

Uses (Importance) of starches: 1 - Nutrient in infant food. 2 - Diluent, filler or disintegrating agent in tablet manufacture. 3 - Antidote in the treatment of iodine poisoning. 4 - Sterilizable maize starch is used as lubricant for surgeons’ gloves.

Starches -Chemical composition of starch: Starch granules are polysaccharide in nature. They are composed of two main components: Amylose Ratio 20% Amylopectin 80% Linear chain Branched chain Solubility in Water soluble Water insoluble Reaction to iodine Blue colour Violet colour

Potato Starch 1 - Origin Wheat Starch Maize Starch Rice Starch Polysaccharide granules obtained from the stem the endosperm of the grains of tubers of Solanum tuberosum Family Triticum Zea mays Oryza sativa Solanaceae vulgare Family Gramineae

Potato Starch Wheat Starch Maize Starch Rice Starch 2 - Physical characters: -Condition -Colour: -Odour: -Taste -Homogenity: -Touch: Fine Powder White Odourless Starchy Homogenous Smooth or gritty

Potato Starch Wheat Starch Maize Starch Rice Starch 3 - Preliminary chemical tests: a- Effect of Insoluble cold water: b- Effect of hot water: c- Effect of acids (HCl): d- Effect of alkalies (KOH): e- Effect of iodine: Colloidal solution, on cooling forms a gel Turbid cloudy solution Bluish violet colour Colour disappears Colour reappears cool

Potato Starch Wheat Starch Maize Starch Rice Starch Polyhedral with rounded angles Polyhedral with Sharp angles 4 - Microscopical Examination 1 - Shape -Oval -Rounded -Elliptical -Triangular -Pyramidal -Oval -Rounded -Lenticular from side view (S. V. )

Potato Starch Wheat Starch Medium 2 - Size: Large Drawing scale 1. 5 -3 cm 1 cm Present, distinct, eccentric, pointed Present, faint, centric , pointed (linear in side view) 3 - Hilum: Hilum Maize Starch Rice Starch Small 0. 4 - 0. 8 cm 0. 2 - 0. 4 cm Present, distinct, centric, cleft or fissured Absent except in large simple granule

Potato Starch 4 -Striations: Present, distinct concentric rings Wheat Starch Present, faint concentric rings Maize Starch Absent Rice Starch

Potato Starch Wheat Starch Maize Starch Rice Starch 4 - cont. Microscopical Examination 5 - Aggregation: Simple, (Composition) compound (2, 3) semicompound Mostly simple, rarely compound Mostly compound, rarely simple

Potato Starch Wheat Starch Maize Starch Rice Starch 5 - Confirmatory chemical Test: 1 - Molisch’s Test: (general test for carbohydrates) 2 - Fehling’s Test: (for reducing sugars) 3 - Iodine test: Starch susp. + 2 -3 dps alcoholic α- naphthol+ 2 -3 dps concentrated H 2 SO 4 on the walls of test tube Violet ring Starch suspension + Fehling solution (blue color) Hydrolyzed starch + Fehling solution (blue color) As before No change in color red colour

Potato ( Low power)

Eccentric hilum Concentric striations Potato (High Power)

oval pyramidal triangular Potato H. P. pyramidal

oval elleptical Potato H. P.

Potato H. P. , compound granule (2) Potato H. P. , compound granule (3)

Potato H. P. semicompound granule

Potato H. P. , Stained with dil. iodine

Wheat (Low power)

Wheat H. P.

Linear hilum Wheat H. P. , side view

Wheat H. P.

Wheat H. P. , Stained with dil. iodine

Maize (Low power)

Cleft hilum Fissured hilum Maize H. P.

Maize H. P. , Stained with dil. iodine

Rice (Low power)

Rice H. P.

Rice stained with dil. Iodine H. P.

Maize H. P. Rice H. P.