Transcript Chemical Constituents

A SEMINAR ON
“Laxatives”
PHARMACOGNOSY
D.C.P-I
A.S.S. College of Pharmacy,
Beed
2012-2013
LAXATIVES
Latin: Laxare:- means to -loosen
Laxatives are the drugs which loose the bowels (intestine)
Depending upon the intensities of drug effects they are categorized as
follows1.
Laxatives: suggest the elimination of soft formed stools (mild
purgatives) ex. Senna, isapgol, liquid paraffin
2.
Purgatives: suggest more fluid evaluation ex. Castor oil, aloe,
rhubarb, cascara
3.
Drastics: act intensely by irritating the mucous membrane of
intestine ex. Jalap, podophyllum, colocynth
4.
Hydrogogues: produce fluid motions ex. croton oil, colocynth
The mechanism of action of laxatives may be either bulk forming, irritant
or emolllient depending upon the chemical nature of active constituent.
Identification
mixes with half its volume of light petroleum ether (40
- 60°)
soluble in alcohol and insoluble in mineral oil
Uses
cathartic, lubrication, soap and textile industry,
in preparation of paints, enamel, varnishes, grease,
polishes, printing ink, spirit
in preparation of ointments, creams and polishes
RHUBARB
Synonyms:- Radix rhei, Rheum, Revandchini.
Biological Source :It dried rhizome of Rheum emodi Wall (Indian rhubarb) family Polygonaceae.
Geographical Source:obtained both from wild and cultivated species in south east China to Tibet and Korea.
Also in Kashmir and Sikkim in India
Collection and Preparation:- The drug mostly obtained from wild plants.
High altitude (more than 3,000 metres)
drought resistant plant and propagated by seeds or from rhizomes
rhizome portion dug up in spring or autumn
Rhizomes cleaned, decorticated and dried
Drug obtained from 6-10 year old plants before flowering season
marketed with cortex intact or partially decorticated.
Macroscopic Characters
rhizomes -barrel shaped, cylindrical or conical(8-10cm) length and 4 cm thickness.
sharp odour and bitter astringent taste.
pale brown to red in colour.
Fracture-irregular granular, abnormal vascular bundles
Microscopic Characters
pieces -show holes,
imedullary rays - brownish red on surface
Fracture-vascular bundles, medullary rays
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Chemical Constituents
contains anthraquinone glycosides (2 to 4.6 per cent )
Anthraquinones with a carboxyl group like rhein and glucorhein.
Anthraquinones without a carboxyl group like aloe-emodin, emodin, chrysophanol,
physcion
Palmidin A , Palmidin B, Palmidin C
gallic acid as glucogallin, along with tannin, catechin an epicatechin
also contains rheinolic acid, pectin, starch, fat and calcium oxalate
Chemical Tests
gives positive test for modified Borntrager's test.
red colour with addition of alkalies due to presence of anthraquinoi glycosides
Standards
Total ash:
Not more than 12.0 %
Acid insoluble ash:
Not more than 1 %
Foreign organic matter: Not more than 1 %
Dilute alcohol soluble extractive : Not less than 30.0 %
Uses
as bitter stomachic, diarrhoea, purgative, estrogenic activity
CASTOR OIL
Synonym
Ricinusoil
Biological Source
It is fixed oil obtained by cold expression of seeds of
Ricinus communis, family Euphorbiaceae
Geographical Source
India (2nd producer, A.P. 60%), Brazil, Thailand, U.S.A.
and Andhra Pradesh, Gujarat, and Karnataka
Description
Colour - pale yellow or colourless
Odour - characteristic.
Taste
- bland to slightly acrid and usually nauseating
It is a viscous and transparent liquid
Standards
Weight per ml -0.945 to 0.965 g
Acid value
-not more than 2
Optical rotation - + 3.5° and + 6.0°
Viscosity - 6-8 poises
Refractive index- 1.4758 and 1.4798
Chemical Constituents
chiefly - triglyceride of ricinoleic acid (80%)
Other glycerides and fatty acids s.a. linoleic, stearic and
isostearic acids
ISPAGHULA
Synonyms: isapgol, isabgol
Biological source:
It consists of dried seeds of the plant known as Plantogo
ovata Forskal belonging to family Plantaginaceae.
Geographical distribution:
In india mainly in gujarat, punjab, south rajasthan.
Morphological characteristics:
Colour: pinkish-grey or brown
Odour: none
Taste: mucilaginous, bland
Shape: ovate like
Size: 10-35mm length and 1 to 1.75mm in width
Chemical constituents:
Contain mucilage, pentosan, sldobionic acid, rhamnose,
fixed oil, and proteins
Uses:
Demulcent, laxative, emollinent, dysentery, in prep
tablets and as stabilizer in icecream industry, in
rheumatic pains