This document discusses several natural laxatives, including aloe, rhubarb, senna, ispaghula, and castor oil. It provides details on the biological source, geographical source, macroscopic and microscopic characteristics, chemical constituents and tests, and uses for each laxative. The document is presented by Dr. Gyaneshwar Singh as part of a course on pharmacognosy at Mangalayatan University in Aligarh, India.

1. Pharmacognosy
Topic:Laxatives
Year: D Pharm first year
Name: Drx Gyaneshwar Singh
Designation:Lecturer
Institute:Mangalayatan University
Aligarh

2. Laxatives
Definition: laxatives are drugs that relieve constipation by
loosening stools or inducing a bowel movement.
Classification of synthetic laxatives drug:
(a).Bulk forming agents(bran or fiber)
(b).Fecal softeners(docusate sodium)
(c).Colonic stimulants(bisacodyl)
(d).Small bowel(osmotic)
(e).Flushers(weak:lactulose,strong:magnesium
sulfate)
Classification of natural laxatives drug: Aloes,Rhubarb,Senna
Castor oil,Ispaghula

3. Aloe vera
Synonyms: Kummari
Mussabar
Biological source:
Aloe vera belong to
family Liliaceae.
 Name of part:dried
juice collected by
incision from the bases
of the leaves.
Geographical
Source: Africa,India
etc.

4. Microscopic Characteristics of Aloe
leaf

5.  Macroscopic:
oColour: bright yellowish or rich reddish brown to
black.
oOdour: odourless
oTaste:bitter

6. Chemical Constituents
•Glyburide,anthraquinone,glycos
ides –aloin barbaloin
•Chemical tests:
•(a)Bromine test:A pale yellow
precipitate of tetrabromaloin is
formed on addition of bromine.
•(b)Schonteten’s test: To a
solution 5ml borax o.2g is added
and it is heated to dissolve
completely.few drops of the
liquid are poured in a test tube
fill with water.A green
fluorescence is produced.
•Uses: purgative,
Antimicrobial-used
for wound healing
sunburn.

7. Rhubarb
Synonym:China
rhubarb, Turky
rhubarb, East indian
rhubarb.
Biological source:
Rhubarb consists of the
peeled dried rhizomes
and roots of ‘’Rheum
palmatum Linn’’belong
to family Polygonaceae
Geographical
Source:
China,Tibet,Korea
,India,West Germany

8. Microscopic Characteristics of Rhubarb

9. Macroscopic:
Colour: Externally it is brown, internally a deep
yellow colour.
Odour: Characteristic.
Taste:Astringent and nauseous .
Chemical Constituents: Chrysophan,chrysophanic acid
emodin, aporetin,rheumic acid
rheotannic acid, erythroretin.

10. Chemical tests
Colour reaction with alkali: To a little powder on
a white tile ,add 2 drops of KOH solution
(5%).the yellow contents of the cells pf the
medullary rays become deep red. Repeat the test
with dilute ammonia solution.
For Presence of Tannins: To a little powder on
a white tile ,add 2 drops of FeCl3 solution.
Note colour , repeat the using water and
compare.

11. Uses
It is used as bitter stomachic in small doses.
It is used as a mild laxative.
It is used as in treatment of diarrhoea.
It is used as an antiseptic , antispasmodic
,purgative
The root is used in the treatment of burn.

12. Senna
Synonym:Cassia senna
Folia senna
Biological Source:Senna
consists of dried leflets of
‘’Cassia angustifolia’’ belong
to family Leguminosae.
Geographical source:India
Africa, Sudan.
Macroscopic:
Colour:Yellowish-green.
Odour:Slight.
Taste: Mucilaginous, bitter.

13. Microscopic Characteristics of Senna

14. Chemical Constituents
Contains rhein ,aloe-
emodin ,kaempferol,
Isormamnetin,

15. Chemical tests
 Borntrager Test:the leaves are boiled with
dilute sulphuric acid and filtered.To the filtere organic
solvent like benzene, ether or CHCl3 is added and
shaken.The organic layers are separated and to it add
ammonia solution.the ammoniacial layer produces pink
to red colour indicating the presence of anthraquinone
glycoside. Little amount of senna leaves extracted with
water by boiling followed by filtrate is treated with 5N
NaOH and sodium hyposulphite, on heating –red colour.
 Uses:Senna is mainly used as a purgative.
It is also stimulant cathartic.

16. Ispaghula
Synonym:Ispaghula
Biological
source:Ispaghula consists
of dried seed ‘’Plantago
ovata’’belong to family
Plantaginaceae.
Geographical Source:
Punjab ,Gujarat, Pune
etc.

17. Macroscopic
Colour :Pinkish gray to brown.
Odour:None.
Taste:Mucilage’s.
Size:10-35mm in length and 1-1.75 mm in width.
Shape: Ovate cymbiform.

18. Microscopic Characteristics of
Ispaghula

19. Chemical Constituents and tests
Essential oils with alpha-pinene,dipentene linalool
,cineol,methyl salicylate,eugenol, bergapten,indole.
Chemical tests: Swelling factors is the criterion for
purity of drug.1gm drug are take in a measuring
cylinder (25 ml) with 20ml of water . The volume
occupied by the seeds after 24 hours of wetting is
measured. Swelling factor for the seeds is 10-14.
• Being the mucilage chemically isapgol gives pink
colour with the solution of ruthenium red.

20. Uses
It is use as laxatives.
Isapgol husk use as demulcent.
It use as emollient in the treatment of chronic
constipation.
Use as amoebic and bacillary dysentery.
It is use to prepare cosmetics.
It is use in tablet preparation and ice-cream
industry.

21. Castor oil
Synonyms:Ricinus Oil
Biological Source:Castor oil
consists dried seed’’Ricinus
Communis’’ belong to
family Euphorbiaceae.
Geographical Source: India
,Brazil ,Thailand
 Macroscopic:
Colour:Pale yellow colourless
liquid
Odour:Slight
Taste:Slightly acrid &
Nauseating

22. Microscopic Characteristics of Castor
seed.

23. Chemical Constituents
Castor oil contain triglyceride of ricinoleic acid
80%.
The viscosity of castor oil is due to ricinoleic
acid.
Other glycerides are isoricinoleic, linoleic,
stearic and isostearic acid.

24. Chemical test
Test Observation Inference
Castor oil+petroleum
ether
Completely soluble in
petroleum ether
Castor oil is present
Castor oil +equal
volume of alcohol
Clear liquid at cool at
o celsius for (3hours)
Castor oil is present

25. USES
Castor oil is cathartic.
Castor seed cake is used as manure ,enzyme
lipase etc.
Dehydrated castor oil .
It is used as lubricant, in paints ,polish ,printing
ink,lip sticks.