Transcript PHG 434 LEC 3x

The active constituents should be extracted and purified before
applying the chemical test.
Preliminary chemical test for active constituents
Qualitative test:
1- Test for glycosides and carbohydrate
2- Test for cardiac glycosides
3- Test for anthraquinone glycosides
4- Test for flavonoids
5- Test for saponin
6- Test for tannins
7- Test for alkaloids
The application of physical constants is applied to the active
principles of drugs such as alkaloids, volatile oils, fixed
oil..etc.
1- Solubility:
-We should determine solubility of A.C. in different
solvents.
-Usually expressed in the following form:
1-g is soluble in ….ml of water, … ml of alcohol, etc.
2- Specific gravity:
- Particularly of the fats and volatile oils.
-Weight of a given volume of liquid compared with the
weight of equal volume of water at specific temperature
and pressure in air.
The specific gravity of anise oil is not less than 0.978 and
not more
than 0.988.
Specific gravity of water =1
Most of V.O. is lighter than water, except V.O. of clove,
Cinnamon (heavier than water).
S.G. is not absolutely constant………….why?
Because other factors affected it:
•maturity of drug from which v.o. is prepared.
•Age of v.o.
•Method of preparation
•Purification
E.g., Jalp is resin is used as purgative is heavier than water.
3- Optical rotation:
Optical activity is the ability of a chiral molecule to rotate the
plane of
plane-polairsed light
dextro (+) rotary (rotate plane of polarized light to right( clock
wise )
levo (-) rotary. rotate plane of polarized light to left ( anticlock wise )
[α]TD = ± α x 100/LXC
[α]TD = ± value of α/degree of rotation
D: sodium line ≈ 580 mm (light that make rotation).
L: Path length of tube in cm
C: concentration in gm .
It is measured by polarimeter.
1-Automatic Digital Polarimeter
range ±45°. Polarimeter cell 100 mm,
200 mm and a sodium lamp.
2-Hand-Held Polarimeter
wave length 589nm, measurement range 35°… +35° optical rotation
Atropine ± zero
Pelocarpine +
Iso pelocarpine -
4- Refractive index:
- Particularly of the fixed and volatile oils (crystals, liquids).
It is a ratio of = sign angle of incidence/sign angle of
refraction of monochromatic beam.
RI measure by refractometer.
-The RI of peppermint oil is not less than 1.4590 and
not more than 1.4650 at 20 ◦C.
5- Congealing point:
- Particularly of fixed and volatile oils.
- The solidification range of fatty acids in olive oil is between
17 and 26◦C.
6- Melting point:
It is of extreme importance, there is a constant range of
m.p. using specific solvent. Cocaine m.p. 96-98 ◦C.
7- UV:
UV light is f importance in several cases, notably in detecting
1- adulteration
a- of rhubarb, where rhapontic rhubarb can easily be
distinguished from genuine Chinese or Indian rhubarb by
its marked fluorescence. Chinese and Indian rhubarb
fluorescence brown, while rhubarb rhaponticum is bright
blue
b- powdered ergot exhibits a strong reddish fluorescence and
can be detected in wheat flour.
UV light is used for determining fluorescence and a play of
colors in connection with certain extracts such as chlorophyll
and the extracts of certain drugs (catechu, senna).
Many alkaloids show distinctive colors under this light,
aconitine (light blue), berberine (yellow), emetine (orange).
An alkaloids such as quinine show fluorescence in acid
solution even in day light, exhibits a much stronger
fluorescence under the quartz lamb
Before a new product is introduced on the market, it must
be proven both safe and effective in preliminary
pharmacologic tests on animals and in quantitative clinical
tests on humans.
Bioassay: Estimation of potency of crude drugs or its
preparation by study of its effect on living organisms like
bacteria, fungal growth or animal tissue or entire animal
Bioassay is the measure of sample being tested capable of
producing biological effect as that of the standard
1- Hepatoprotective activity
Male\Female albino rat
Alcohol, paracetamol, rifampicin, carbon tetrachloride
 Hepatocyte culture (Hepatic cells)
The parameter used to asses toxicity:
a) Physiological(Hexobarbital hypnosis)
b) Biochemical serum estimation of enzymes like SGPT, SGOT
c) Histopathological-(liver tissue necrosis and fatty
degeneration )
2- Hypoglycemic activity
 Alloxan (180-250 mg\ml) or sterptozocin(induce
diabetes )
Rabbits, rats or mice
Hypoglycemic plant extracts like fenugreek
Glucose tolerance effect or glucoautoanylsis
RIA or ELISA are used for measurement of insulin levels
3- Anti-inflammatory activity
Rat ,Albino adult mice
Mechanical cause, infection or autoimmune disease
Histamine, kinins and prostaglandin causing inflammation
Carrageenan irritant substance
Reduction of PAW oedema is measured
4- Anti-ulcer activity
Anti-ulcerogenic plant like liqurice, white cabbage juice
Ulcer inducer:
i- Chemicals ( alcohol, drugs)
Ii- stress (immobilization and cold)
Three group of animals
1-treated with normal saline
2-treated with ulcerogenic
3- tested group
4- reference group
Microbiological activity
A- Cylinder plate method (cup method)
Measurement of diameters of microbial growth inhibition
surrounding cylinders containing various dilution of test
compound and compared with reference
B- Turbidimetric method
Based on inhibition of microbial growth as indicated by
measurement of turbidity(transmittance) of suspension of a
suitable micro-organism in fluid medium to which have been
added tested compound
Change in transmittance produced by tested compound
are compared by known concentration of slandered