Phytochemicals

What are phytochemicals?

Phytochemicals are non-nutritive plant chemicals that have protective or disease preventive properties. They are nonessential nutrients, meaning that they are not required by the human body for sustaining life. It is well-known that plant produce these chemicals to protect themselves but recent research demonstrate that they can also protect humans against diseases. There are more than thousand known phytochemicals. Some of the well-known phytochemicals are lycopene in tomatoes, isoflavones in soy and flavanoids in fruits.

What is Phytochemical Screening?

It is a process of tracing plant constituents. For example you want to found out if a certain plant contains alkaloids (a plant constituent) then, you will be performing a phytochemical screening procedures for alkaloids (in this case mayer's and Wagner's test). There are general plant constituents that can be performed with a standard test.

What are the different reagents used in Phytochemical Screening? How are these prepared?

REAGENT-  is a "substance or compound that is added to a system in order to bring about a chemical reaction, or added to see if a reaction occurs." Although the terms reactant and reagent are often used interchangeably, a reactant is more specifically a "substance that is consumed in the course of a chemical reaction". Solvents, although they are involved in the reaction, are usually not referred to as reactants. Similarly, catalysts are not consumed by the reaction, so are not described as reactants.

-Mayer’s Reagent

(Alkaloid)

Procedure:
0.4 g of Mercuric Chloride is dissolved in 15 ml water and poured into a solution of 1.25 Potassium Iodide in 2.5 ml of water. Sufficient water was added to make 25 ml.

-Molisch’s Reagent

(Carbohydrates)

Procedure:
1.5 g of Naphthol was dissolved in 10 ml of ethanol

-Acetic acid
Ferric Chloride
(Glycosides)

Procedure:
Few drops of ferric chloride was mixed with 2.5 ml of acetic acid

-Distilled Water
(Saponins)
Procedure:
Pure extract of substance was mixed with distilled water

-Distilled Water
Ferric Chloride
(Phenols)

Procedure:
Mix Distilled Water and Ferric Chloride

-Ferric Chloride solution
(Tannins)
Procedure:
Dissolve 13.5 g of Ferric Chloride in 10 ml water with 0.25 ml of concentrated Hydrochloric Acid Dilute to 100 ml


-Sodium Hydroxide Solution
(Anthocyanin)
Procedure:

Dissolve 0.4 g of Sodium Hydroxide in 10 ml of water.

-Nitric Acid
(Protein)
Procedure:
Mix Nitric Acid to the solution

-Sodium Hydroxide Solution
(Flavonoids)
Procedure:
Dissolve 0.4 g of Sodium Hydroxide in 10 ml water.

What are the indicators of the presence of each phytochemical?

Alkaloids
In Determinig the presence or absence of alkaloids, Mayer’s reagent test was used. It is a mixture of mercuric chloride solution and potassium iodide solution. Alkaloid is present if there is a formation of green or white precipitations.

Carbohydrates
To determine if carbohydrates were present, Molisch’s reagent is used. It was prepared by mixing naphthol and ethanol. Carbohydrates were present if there is a formation of red or purple when the extract was mixed with Molisch’s reagent.

Glycosides
In testing the presence of glycosides, acetic acid and ferric chloride was used. There is a presence of glycosides if the color of the mixture extract and reagent became blue-green.

Saponins
To test of Saponins were present on the extract, ditilled water was added and then chook for fifteen minutes. When there is a formation of foam or frothy bubbles on the mixture, it indicates that saponins were present.

Phenols
The picture shows that traces of Phenols were present in the extract. The brown extract changes into the green color.The formation of blue or green color indicates the presence of phenols.

Tannins
To determine the presence of tannins, ferric chloride solution was used. When there is a formation of dark blue or greenish black color indicates the presence of tannins.

Anthocyanin
The presence or absence of anthocyanin as determined by the use of sodium hydroxide solution., when there is a formation of blue or green precipitates. It indicates that anthocyanin Is present.

Protein
The formation of yellow, yellow-green or light green color when the extract was mixed with nitric acid indicates the presence of protein.

Flavonoids
Sodium Hydroxide solution was used to determine the presence of flavonoids. Formation orange of intense yellow color indicates its presence.
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