Introduction to Alkaloids: A Comprehensive Study Guide for Pharmacy Students, Slides of Pharmacognosy

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INTRODUCTION

TO

ALKALOIDS

PREPARED BY: MIZANUR FAKIR ROLL NO: 34 B.PHARM 6TH^ SEM.

CONTENT

 DEFINITION

 FUNCTIONS IN PLANTS

 PROPERTIES

 TYPES

 CHEMICAL CLASSIFICATION

 IDENTIFICATION TEST

 PHARMACEUTICAL APPLICATION

 REFERENCE

1.Act as protective against insects ,

herbivores due to their bitterness toxicity.

2. Source of nitrogen in nitrogen deficiency.

3. Sometimes act as growth regulator.

FUNCTION IN

PLANTS

1.Physical properties :

• Colorless
• Crystalline solid
• It has sharp melting point
• Some are Amorphous gums example: Opium.
• Some are volatile and liquid Example is Nicotine
• Some are colored Example: Betadine is red in colour, berberine is yellow in colour. PROPERTIES

• (^) Alkaloids show basic character and due to this they are very much sensitive to decomposition and cause a problem during storage because of this reason they are made into salt form.
• Alkaloids are insoluble in water.
• Pseudo and proto alkaloids show more solubility in water. Example: Caffeine (freely soluble in water)

Decomposition of alkaloids:

There are three main types of alkaloids: (1) true alkaloids/ typical/ heterocyclic alkaloids (2) protoalkaloids/ non-heterocyclic/ atypical alkaloids (3) pseudoalkaloids.

Types of alkaloids:

2.Protoalkaloids :

. Nitrogen is not present in the heterocyclic ring but present in the side chain

• These are simple amines and basic in nature. Example: Ephedrine

3.Pseudoalkaloids

• These are steroidal, terpenoids and purines alkaloids.
• Not derived from amino acids.
• They do not show typical characters of alkaloids but give standard test for alkaloids. Example: Caffeine (Murexide test)

Test Reagent Composition Positive Colour Change Dragendorff’s Reagent Potassium Bismuth Iodide Reddish-brown Mayer’s Reagent Potassium mercuric iodide White or pale yellow ppt Hager’s Reagent Picric acid Yellow Wagner’s Reagent Solution of iodine in potassium iodide Yellow or brown ppt Murexide Test KCL + few drops of HCL , expose to NH Purple.

IDENTIFICATION TEST

Reference:

• (^) Text book of Pharmacognosy by C.K. Kokate, Purohit, Gokhlae (2007), 37th Edition, Nirali Prakashan, New Delhi.

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