Isolation and detection of active principles, atropine from belladonna

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BACKGROUND

Atropine is an alkaloid containing tropane belongs to family Solanaceae.

Aim: Aim of the experiment is to isolate and detect the active constituent, atropine present in belladonna. The herb of belladonna consists of dried leaves of Atropa belladonna Linn. Mainly, it is cultivated in England, European countries, India (Himachal Pradesh, Kashmir). For the cultivation it needs an altitude of 1400 m above the sea level. The chemical constituents of the drug includes 1% alkaloid, l-hyoscyamine. Atropine is the racemate form of l-form and d-form of hyoscyamine.¹

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REQUIREMENTS

Apparatus: Test tube,

Extraction unit,

Measuring cylinder,

Filter paper,

Funnel,

Beaker

Chemicals: Ether,

Benzene,

Na₂CO_3,

Acetic acid,

Sodium sulphate,

Alcohol,

NaOH,

HNO₃

KOH

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PROCEDURE

Isolation of atropine

From the juice of the powdered form of drug, atropine is isolated. By using the aqueous solution of Na₂CO_3, the powdered drug material is thoroughly moistened and extracted by using ether and benzene. From the solvent, the free base of alkaloid is extracted with acetic acid. To remove the colouring matter the acid solution is shaken with ether and precipitation of alkaloid is carried out by using Na₂CO₃. Then the solution is filtered, washed and dried. Again the dried sample is dissolved in acetone or ether and dehydrated by using anhydrous sodium sulphate before filtration. A crude crystal of atropine is obtained after the concentration of filtrate following cooling of the solution. For the complete racemization of hyoscyamine to atropine, we have to dissolve the crude crystalline sample in alcohol and NaOH solution.²

Detection of atropine

The sample solution is diluted and treated with concentrated HNO₃. Evaporation of the mixture takes place for the drying of sample on the water bath and it produce a pale yellow colour residue. A drop of freshly prepared KOH is added to the yellow colour residue and the colour changes the violet (Vitali-Morin reaction).²

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CONCLUSION

The active constituent atropinewas isolated and detected from belladonna plant. It is used as antidote for anticholinesterase inhibitor toxicity, treatment of bradysystolic cardiac arrest, pupil dilator, for uveitis treatment.

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REFERENCES

Kokate CK, Purohit AP, Gokhale SB. Druds containing alkaloid (belladonna), Text Book of Pharmacognosy, 51 edition, Nirali Prakashan, pune. 2015:15-44.
Shah B, Seth AK. Isolation of phytopharmaceuticals, Text book of Pharmacognosy and Phytochemistry, 2^nd edition. CBS Publishers & Distributors pvt ltd. 2014: 447.