science

1. NAME: ADZOTOR DENISON
INDEX NO_: 8028812
EXPERIMENT: O.3.1.2 & O.3.1.3
DEMONSTRATOR: Mr. BRIGHT VIGBEDOR
DATE: 18th November, 2014.
AIMS:
determine the presence or absence of various secondary metabolites in a plant
INTRODUCTION:
Phytochemical screening is a process of submitting plant parts to various chemical test in order to
extract secondary plant constituents in them, it also gives us basic information concerning the
medicinal importance of the plant extract. After every chemical reaction that takes place in plants,
secondary metabolites are produced. phytochemical screening and quantitative estimation of the
chemical constituents of indicates the presence of various metabolites consisting of reducing
compounds, free radicals and other chemical constituents scavenging compounds such as gums,
flavonoids, alkaloids, reducing sugars, terpenoids, saponins, coumarins, tannins, cardiac glycosides
anthraquinones, and phlobatinins and other phenolic compounds. plants have high medicinal value. These
plants have a wide range of uses by all sections of the society either directly or indirectly in traditional medicine and
pharmaceutical preparation of modern medicine. Phytochemicals having biological activity have had great utility as
pharmaceuticals and pharmacological actions. As time goes on, statistics indicate the high increase in various
diseases and ailments due to improper intake of diets. Diests taken of late mostly contain high values of fats, proteins
and carbohydrates which are all which are all processed and have a less value of natural products. Eating much
natural plant food give a good amount of fibre, vitamins natural proteins and many more beneficial nutrients from
organic sources. analysis and research indicates that plant leaves are a good source of metallic
elements, protein and sugar. Due to the possession of these constituents and their characteristic
effects, users have more benefits when they use these as a substitute of sugar in various food
preparations. A combination of these phyto chemicals can be found in the same plant with different
functional groups, molecular structure and active ingredients. this compounds can be extracted using
chemical additives and various extraction and separation mechanisms. This lab is aimed at identifying
phytochemicals in a given plant sample and extracting them if present.
CHEMICALS USED:
 dil. H2SO4
 NaOH
 Fehling’s solution
 conc. HCL
 dil. NH3
 Ethanol
 Antimony Trichloride
 Chloroform
 Acetic anhydride
 Potassium Mercuric Iodide
APPARARTUS USED:
 Test tubes
 Beakers
 Water bath
 Filter paper
 Crucible
 Magnesium ribbon

2. Procedure, observations and Table of results
Test Observation Inference
1.Plant material + 10ml distilled
Formation of froth (foam)
water and heated for 3-5 mins and
which persisted for some time
filtered, and filtrate was shaken
vigorously.
Presence of saponins.
2a. Sample + water+ heat
+ NaOH
+ felling solution
+ heat
2b. Sample + H2SO4 + heat
+ felling solution
+ heat.
Light yellow solution formed
Yellow solution formed
Green gel. Ppt formed
Green ppt formed.
Light yellow solution formed
Green chalky ppt. Formed
Green chalky ppt formed
Glycosides absent.
3. sample + alcohol
+ magnesium ribbon followed by
conc. HCl
Sample + NH3
Green colour formed
No colour change.
Exhothermic.
Green colour formed.
Flavonoids absent
Flavonoids absent
Flavonoids absent
4. sample + ethanol, evaporated to
dryness in crucible and diluted in
chloroform + acetic anhydride +
conc. H2SO4
Extract in chloroform + conc.
H2SO4
Formation of green colour
Green colour formed
No trepanoids or steroids
present.
Trepanoids and steroids absent.
5. 0.5g sample+ 20ml dil. H2SO4
and boiled. Filtrate + equal volume
of benzene.
Separated benzene layer + NH3
Coloules ammoniacal layer
formed.
Absence of anthraquinone
glycosides.
6. Sample + 10ml ethanol.
Extract + 3ml antimony trichloride.
Sample + 10ml ether
Extract + conc. H2SO4
Green colour formed.
Redish colour formed.
Light brown acid layer
Absence of carotenoids.
7. sample + 25ml KOH and 4ml
H2O2boiled and filtered.
Filtrate acidified with acetic acid.
Extract with benzene (15ml)
NH4OH
Separation of two layers of
benzene and the aqueous phase.
Colourless alkaline layer
formed.
Anthraquonones absent
8. 5g of powded sample + 10ml of
1%HCl. Left to stand for 30mins.
With occasional stirring and
filtered.
Filtrate + saturated solution of
picric acid.
Light green colour formed.
No precipitate formed.
Absence of alkaloids
Sample + water
Test tube is covered with filter
paper moistened with dil. NaOH
and placed in a hot water bath.
Paper is removed and exposed to
UV. Light after 15mins.
Appearance of yellow green
florescence.
Coumarines present
DISCUSSON.
The experimental results indicated that, nine tests were performed to determine the presence of
phytochemicals but only two proved positive. Thus were present in the plant sample given. Sarponins
and coumarines were found to be present after the analysis whiles glycosides, flavonoids, terpenoids

3. and steroids, carotenoids alkaloids, anthraquinones and anthraquinone glycosides where found to be
absent.
In the test for sarponings, there was an observation of Formation of froth (foam) which persisted for
some time indicating a positive results for the presence of saponins. The soapy nature observed is also
an indication of their sulfuctant characteristics. In the test for glycosides, the analysis results indicated
that, glycosides were absent with an observation of Light yellow solution formed, Yellow solution
formed ,Green gel. Ppt formed, Green ppt formed.Light yellow solution formed, Green chalky ppt.
Formed,Green chalky ppt formed per their respective procedures instead of the formation of a reddish
brown ppt. in test tube containing H2SO4 filtrate, and the absence of ppt in the other test tube. Fahlings
solutions was used because of the presence of suger in glycosides. The test for trepanoids and
steroids also proved negative indicating their absence in the plant sample because expected
observations indicating their presence were not made. Carotenoids were also found to be absent in the
sample due to the fact that, Light brown acid layer was observed in the final analysis instead of a
dark- blue, blue -violet or greenish- blue colour of the acid layer. Coumarines were found to be
present with an observation of yellow green florescence which was the expected observation for its
presence. The test for alkaloids, anthraquinones and anthraquinone glycosides gave a result which
indicated that they were absent since observations made did not match with expected observations in
the manual. From the nine test done, only two of the phytochemicals proved to be present in the plant
sample used. This is an indication of a low level of expected phytochemicals but there can be the
presence of other phytochemicals which were not tested for.
PRECAUTIONS:
 Protective clothes were worn to prevent the skin and eyes from hazardous chemicals during
spillage respectively.
 All the glassware’s were well washed before the experiment to prevent contamination.
 All tests were carried out in the fume hood to prevent the inhalation of poisonous gases.
 Water bath was used for all heating’s done.
1. problems uncounted with measurement might affect result indirectly.
2. easy identification of colour changes immediately is also a factor that might have affected the
efficiency of this results obtained.
CONCLUSION:
The experiment can be termed successful since some of the phytochemicals were found to be present
and respective results were obtained for the ones that were absent.
REFERENCES:
1. knust department of chemistry third year, lab manual. Page 34-36.
2. Atawodi, S.E. (2005). Antioxidant potential of African medicinal plants. AfricanJournal of
Biotechnology4(2):128-129.
3. Burkill, H.M. (1985). The useful plants of West Tropical Africa.2ndEdition, Families A–D.
Royal Botanic Gardens, Kew, United
Kingdom. Vol. 1 pp.960.
4. Calzyme, (2004). Alpha-glucosidase manufactures. Calzyme laboratories Ltd.
Online catalog.