Botany and medicinal plants

Pharmacognosy Department Faculty of Pharmacy

Cairo University

Dusting Powders

1-Potato Starch

2-Wheat Starch

3-Maize Starch

4-Rice Starch

(Fine powders)

Starches Non- Starches

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:

4- Sterilizable maize starch is used as

lubricant for surgeons’ gloves.

1- Nutrient in infant food.

2- Diluents, filler or disintegrating agent in tablet

manufacture.

3- Antidote in the treatment of iodine

poisoning.

3 4 October 2015

Starches Chemical composition of starch:

Starch granules are polysaccharide in nature.

They are composed of two main components:

Amylose Amylopectin

Ratio 20% 80%

Linear chain Branched chain

Solubility

in Water Water soluble Water insoluble

Reaction

to iodine Blue colour Violet colour

4 4 October 2015

Potato

Starch

Wheat

Starch

Maize

Starch

Rice

Starch

1-Origin Polysaccharide granules obtained from

the stem

tubers of

Solanum

tuberosum

Family

Solanaceae

the endosperm of the grains of

Triticum

vulgare Zea mays Oryza sativa

Family Gramineae

5 4 October 2015

Potato

Starch

Wheat

Starch

Maize

Starch

Rice

Starch

2- Physical characters:

Fine Powder

White

Smooth

Starchy

Homogenous

Odourless

Smooth

or gritty

-Colour:

-Odour:

-Taste

-Touch:

-Homogenity:

-Condition

6 4 October 2015

Potato

Starch

Wheat

Starch

Maize

Starch

Rice

Starch

3- Preliminary chemical tests:

a- Effect of

cold water:

b- Effect of

hot water:

Insoluble

Colloidal solution, on cooling forms a

gel

e- Effect of

iodine:

Bluish violet colour Colour disappears

cool Colour reappears

c- Effect of

acids (HCl): Turbid cloudy solution

d- Effect of

alkalies (KOH): Turbid cloudy solution

7 4 October 2015

Potato Starch Wheat

Starch

Maize

Starch

Rice

Starch

4- Microscopical Examination

1- Shape

-Oval

-Rounded

-Elliptical

-Triangular

-Pyramidal

-Oval

-Rounded

-Lenticular

from side

view

Polyhedral

with

rounded

angles

Polyhedral

with Sharp

angles

(S.V.) 8 4 October 2015

Potato Starch Wheat

Starch

Maize

Starch

Rice

Starch

2- Size: Large Medium Small

Hilum

Present,

distinct,

eccentric,

pointed

Present,

faint,

centric ,

pointed

(linear in

side view)

Present,

distinct,

centric,

cleft or

fissured

Absent

except

in large

simple

granule

1.5-3 cm 1 cm 0.4 - 0.8 cm 0.2- 0.4 cm

3- Hilum:

Drawing scale

9 4 October 2015

Potato Starch Wheat

Starch

Maize

Starch

Rice

Starch

4- cont.Microscopical Examination

4-Striations:

Present,

distinct

concentric

rings

Present,

faint

concentric

rings

Absent

10 4 October 2015

Potato

Starch

Wheat

Starch

Maize

Starch

Rice

Starch

4- cont.Microscopical Examination

5- Aggregation: Simple,

compound (2,3)

semicompound

Mostly simple,

rarely compound

Mostly

compound

, rarely

simple

simple

compound

Semicompound

11 4 October 2015

Potato

Starch

Wheat

Starch

Maize

Starch

Rice

Starch

5- Confirmatory chemical Test:

1- Molisch’s

Test:

(general test

for

carbohydrates)

Starch susp. + 2-3 dps alcoholic α- naphthol+ 2-3 dps

concentrated H2SO4 on the walls of test tube

Violet ring

2- Fehling’s

Test:

(for reducing

sugars)

Starch suspension + Fehling solution

(blue color) No change in color

Hydrolyzed starch + Fehling solution

(blue color)

red colour

3- Iodine test: As before

12 4 October 2015

Potato ( Low power) 13 4 October 2015

Potato (High Power)

Concentric striations

Eccentric hilum

14 4 October 2015

Potato H.P. pyramidal

oval

triangular

pyramidal

15 4 October 2015

elleptical

Potato H.P.

oval

16 4 October 2015

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

compound granule

(2) 17 4 October 2015

Potato H.P.

semicompound granule

18 4 October 2015

Potato H.P., Stained with dil. iodine 19 4 October 2015

Wheat (Low power) 20 4 October 2015

Wheat H.P. 21 4 October 2015

Wheat H.P., side view

Linear hilum

22 4 October 2015

Wheat H.P. 23 4 October 2015

Wheat H.P., Stained with dil. iodine 24 4 October 2015

Maize (Low power) 25 4 October 2015

Maize H.P.

Fissured hilum

Cleft hilum

26 4 October 2015

Maize H.P., Stained with dil. iodine

27 4 October 2015

Rice (Low power) 28 4 October 2015

Rice H.P. 29 4 October 2015

Rice stained with dil. Iodine

H.P. 30 4 October 2015

Rice H.P. Maize H.P.

31 4 October 2015