2. Aim -
To determine the phytochemicals present in the medicinal
plants and their use and properties.
The phytochemicals are to be found are –
Tannins
Phlobatannins.
Saponin.
Flavonoids.
Steroids.
Terpenoids.
Cardiac glycosides.
3. Phytochemicals
Phytochemicals are the chemically compounds that
occur naturally on plants.
Some are responsible for colour and other organoleptic
properties such as –
Purple colour of blue berries.
Smell of garlic etc.
They have been considered as medicines for centuries.
4. Medicinal Plants
We call a plant “medicinal” when it is used by the community
to treat an ailment or to treat a condition in human body
other than normal condition.
Medicinal properties are proven by many medicinal streams
such as Ayurveda, Unani, Siddha, Folk etc.
Medicinal plants can be grouped under these catogories –
Curative medicinal plant.
Preventive medicinal plant.
Promotive medicinal plant.
5. List of Medicinal plants
In Arunachal Pradesh-
Common name Scientific name
1. Vasa. Adhatoda vasica.
2. Pibli. Piper mullesua.
3. Piper. Piper longum.
4. Kachnar. Phanera variegata.
5. Sarpagandha. Rauvolfia serpentina.
6. Kutki. Picrorrhiza kurrua.
7. Himalayan yew. Taxus baccata L.
6. In Tinsukia district-
Common name Scientific name
1. Bon amlokhi. Phyllantus nirurii.
2. Nayantara. Catherantus roseus.
3. Kaharaj. Eclipta prostraia.
4. Dupor tenga. Bryophyllum pinnata.
5.Manimuni. Centella asiatica.
7. Methods to determine phytochemicals
1. Test for Tannins – About 0.5 g of the dried sample was
boiled in 2o ml of water in a test tube and filtered. A few
drops of 0.1% ferric chloride was added and observed for
brownish green or a blue-black colouration.
2. Test for Phlobatannins – Deposition of a red precipitate
when an aqueous extract of each plant sample was boiled
with 1% aqueous Hcl acid was taken as evidence for the
presence of phlobatannins.
8. 3. Test for saponin – About 2 g of the powdered sample was
boiled in 20 ml distilled water in a water bath and filtered.
10 ml of the filtrate was mixed with 5 ml of distilled water
and shaken vigrously for a stable persistent froth. The
frothing was mixed with 3 drops of olive oil and shaken
vigrously, then observed for the formation of emulsion.
4. Test for Flavonoids – There are two methods, which are
used to determine the presence of flavonoids in a plant
sample.
Method-1 – 5 ml of dilute ammonia solution is added to a
portion of the aqueous filtrate of each plant extract
followed by addition of conc sulphuric acid. A yellow
colouration observed in each extract indicates the presence
of flavonoids. The yellow colour disappears on standing.
9. Method-2 – A portion of the powdered plant sample in
each case is heated with 10 ml of ethyl acetate over a steam
bath for 3 mins. The mixture was filtered and 4 ml of the
filtrate was shaken with 1 ml of dil ammonia solution. A
yellow colouration was observed indicating a positive test
for flavonoids.
5.Test for Steroids – 2 ml of acetic anhydride is added to 0.5 g
ethanolic extract of each sample with 2 ml of sulphuric
acid. The colour changed from violet to blue or green in
some samples indicating the presence of steroids.
10. 6. Test for Terpenoids – (Salkowski test)
5 ml of each extract is mixed in 2 ml of chloroform and
conc sulphuric acid(3 ml) is carefully added to form a layer.
A reddish brown colouration 0f the interface is formed to
show positive results for the presence of terpenoids.
7. Test for Cardiac glycosides – (Keller-Killani test)
5 ml of each extract is treated with 2 ml of glacial acetic
acid containing one drop of ferric chloride solution. This is
underlayed with 1 ml of conc sulphuric acid. A brown ring
at the interface indicates a deoxysugar characteristics of
cardenolides. A violet ring may appear below, the brown
ring while the acetic acid layer, a greenish ring may form
just gradually throughout thin layer.
11. Observation
Plants containing different phytochemicals –
In Arunachal Pradesh
1. Vasa- (Adhatoda vasica)
In english commonly known as Malabar nut.
Its botanical name is Justicia adhatoda.
Uses –
For Asthama and cough.
For Malaria and Mensturation problems.
For Tubercolosis and Stomach problems.
12. Phytochemicals contained by Vasa are
Saponin – Effervesence observed.
Flavonoids – Yellow colour observed.
Terpenoids – Reddish brown colouration.
Cardiac glycosides – Ring formation.