Purine bases

the word purine ( pure urine ) was coine by the German cheamist emil fischer in 1884.
He synthesized it for the first time 1899.
The starting material for the reaction sequenc was uric acid, which had been isolated from kidney stones by Scheele in 1776.
purines are found in high concentration in meat and meat products,especially internal organs such as liver and kidney.
In general , plant – based diets are low in purines .
Purines nucleus is a heterocyclic aromatic organic compound consisting of pyrimidine ring fused to 5-membered imidazole ring known as xanthine.
Purines unlike other alkaloids don’t give positive results with the general testes of alkaloids ,instead muroxide test is used in its identification.
Purines are present as methylated compounds, which are:
1- caffeine (1,3,7-tri methyl xanthine).
2- theophylline (1,3-di methyl xanthine).
3- theobromine(3,7-di methyl xanthine).

Stimulation of the CNS.
2- Diuretic effects.
3- Increase gastric acid secretion.
4- Relaxation of the bronchial smooth muscle (theophylline).
5- Positive inotropic and chronotropic effect on the heart.