Aim: Extraction and identification of Atropine from belladona leaves


Reference: 

1. Khadbadi, S. S., Deore, S. L., & Baviskar, B. A. (2011). Experimental phytopharmacognosy. Nirali

 prakashan, page, (47).


Theory:

Atropine is a tropane alkaloid obtained from Atropa belladona (Deadly Night shade), Datura

(Datura metal) of family Solanaceae it is used as anticholinergic agent. It is mydriatic and

antidote in opium poisoning.


Structure 

The above mentioned plants contain the atropine in the racemic form. That is hyoscyamine or

atropine. These alkaloids are true alkaloids they obeys the general solubility property i.e. 

the pure alkaloid are soluble in organic solvents and alkaloid salts are soluble in water.

In the following mentioned procedures. The plant material is treated with alkali so that

the alkaloids converts to pure bases; in addition due to alkali treatment the hyoscyamine

also converts to atropine (the targeted pure phytoconstituent) followed by extraction with

organic solvents. In further steps, to separate the unwanted phytoconstituents from

targeted one, the alkaloids are converts to salts and pure form.

Atropine -289.37

( C17H23NO3)



Chemicals and Apparatus

Soxhlate assembly,  heating mental, diethyl ether, potassium carbonate, ethanol, heating

mental, separating funnel, funnel, measuring cylinder, evaporating dish, beakers etc.


Extraction Method 1:

1.   Take the accurately weighed quantity of the above mentioned crude drug and powder to obtain

      coarse size particles.

2.   Moisten the powder with sodium carbonate solution Extract the blended mixture in ether.

3.   Filter the ether extract. Extract the filtrate with aqueous acetic acid.

4.   Treat the aqueous acidic layer with solvent ether and separate both layers.

5.   Discard ether layer. Treat acidic layer  with sodium carbonate to obtain precipitates tropane

      alkaloids.

6.   Filtrate the precipitates and dry it. Mix the residue with diethyl ether, filter and concentrate the

       filtrate

7.   Collect the crystals and add alcoholic NaOH and recrystallize with acetone


Extraction Method 2:

Take the accurately weighed quantity of any of the above mentioned crude drug and powder to obtain coarse size particles. Moisten the powder with sodium carbonate solution. Extract the blended mixture in ether. Filter the ether extract. Extract the filtrate with aqueous acetic acid. Treat the aqueous acidic layer with solvent ether and separate both layers. Discard ether layer. Treat acidic layer with sodium carbonate to obtain precipitates of tropane alkaloids. Filter the precipitates and dry to obtain residue. Dissolve this residue in diethyl ether. Filter and concentrate the filtrate. Atropine crystals will be separated out. Filter the crystals and dissolve in alcohol containing NaOH solution so that hyoscyamine can be converted to atropine. Recrystalise the atropine sulfate from acetone.


Evaluation – chemical test:

Vitali Morin test – to the drug fuming nitric acid is added & it is evaporated to dryness.

Methanolic KOH is added to the acetone solution of the nitrated residue. It develops a violet

colour.


Result:

Observation

·         Weight of plant taken (gm) (a):

·         Weight of atropine obtained (gm) (b):

·          % yield = (b*100)/a