Xanthines are a compound group that are xanthine derivatives (a purine base). These compounds are basically alkaloids and they include widespread gentle stimulants like caffeine and theobromine that are present in chocolate. Some xanthines also have therapeutic applications and are generally used for treating asthma as well as other respiratory conditions. Xanthine has a role in human physiology and it is an intermediary in uric acid production. Moreover, a genetic disorder called xanthinuria is a condition that gets in the way of metabolism of xanthine.
There are several xanthine derivatives and they are usually used for their action as mild stimulants and also in the form of bronchodilators, especially in treating asthma and symptoms of influenza. Different from other more powerful stimulants such as sympathomimetic amines, primarily xanthines work to oppose the exploits of adenosine. At the same time, they work to enhance alertness in our central nervous system (CNS).
In fact, the primary chemical structure of xanthines is purine-base. This is a unique kind of molecule having two aromatic rings containing carbon, hydrogen and nitrogen molecules. These compounds are very widespread, as two of the bases of xanthines are basically constituents of DNA and RNA. They are adenine and guanine. Apparently, it is believe that xanthine is also present extra terrestrially. This theory is based on an analysis of the Murchison meteorite found in Australia. This meteorite was found to contain xanthine.
Xanthines work as gentle stimulants and they aid in improving breathing. As a result, xanthines are useful for treating conditions like asthma, chronic bronchitis and emphysema. The most commonly used xanthine derivatives that are used in medicine contain either a methyl or CH3 group. In fact, xanthines have different modes of actions and different drugs apply these compounds as different selectives.
In addition, xanthines increases the heart rate and, at the same time, have an effect on our central nervous system. Nevertheless, the use of these compounds can also have noxious side effects. It is for this reason, xanthines are not considered as first class drugs and usually they are not selected for asthma treatment. On the other hand, scientists have developed synthetic xanthines that are not as harmful as the natural compounds and, hence, have lesser side effects. Here is a piece of advice. In order to reduce or restrict the chances of these side effects, you need to avoid or restrict chocolate or caffeine consumption while taking xanthines.
It is worth mentioning here that xanthine is a vital intermediate in degradation of purines. Hence, as a consequence of this these compounds are present in nearly all tissues and fluids of the human body. The final product of breaking down purines is uric acid, which is generally expelled from the body via urination. However, when the uric acid is not expelled from the body properly, it may accumulate in the joints and cause an excruciating condition known as gout.
Xanthine is metabolized in the liver by an enzyme secreted in this organ. This enzyme is called xanthine oxidase (XO). It is also called xanthine dehydrogenase and it undertakes two different types of reactions. In a reversible reaction, xanthine oxidase (XO) or xanthine dehydrogenase converts hypoxanthine - a transitional breakdown produce from adenine to xanthine. At the same time, this enzyme is also capable of reversibly convert xanthine into uric acid. Sometimes allupurinol, which is basically an inhibitor of xanthine oxidase (XO), is used medicinally for treating gout, as it helps to prevent xanthine build up in the joints.
A number of people suffer from a genetic disorder known as xanthinuria, which means they do not possess the ability to produce xanthine oxidase (XO). As a result, they have a very high concentration of these compounds in their blood. This, in turn, can result in accumulation of uric acid in their kidneys and muscles. In the kidneys, the build-up of xanthines may result in development of xanthine stones. In such cases, there is a chance that the kidneys of these people may fail to function completely. This is a rare condition and as of date there is no treatment available for the problem. Therefore, it is strongly recommended that such patients should avoid consumption of fluids that may contain plenty of xanthenes. Instead, they need to drink plenty of other fluids.
The medicinal applications of xanthines are quite few owing to the prevalent effects - toxic side effects of using this compound. As a result, it is just a second-line treatment for asthma. The therapeutic level of xanthines is anything between 10 micrograms/mL blood to 20 micrograms/mL blood. Often, use of xanthines may result in toxicity and the signs of this include nervousness, nausea, tremor, and arrhythmia/tachycardia.
Methylated xanthines (also known as methylxanthines) usually include aminophylline, caffeine, paraxanthine, IBMX, pentoxifylline, theophylline and theobromine. Methylated xanthenes not only affect the airways, but also arouse the heart rate, force of concentration as well as cardiac arrhythmias at very high concentrations. When used in high doses, xanthines may also cause convulsions, which are not curable by anticonvulsants. Moreover, methylated xanthines stimulate secretions of pepsin and acids in the gastrointestinal (GI) tract. Cytochrome P450, which is present in the liver, metabolizes methylxanthines.
When you swallow or inhale xanthines in elevated amounts, xanthines may prove to be very harmful for our health. The same thing happens when xanthines are exposed to your eyes. When applied externally, they may result in allergic reactions.
While we are writing about xanthines, it is essential that we also talk about purines. Precisely speaking, purines are organic compounds that are found extensively all over nature. In fact, purines are present in all the cells of our body and also in a wide variety of foods that are plant-based as well as animal-based. Purines are colorless and have a crystalline structure. Once inside our body, purines present in the various foods we consume are broken down into uric acid in the digestive process. Despite the fact that purines have a vital role in synthesizing DNA as well as RNA, very high concentration of purines may often result in various health problems, which may include hyperuricemia and gout.
Purines are a member of nitrogen-containing molecule family, which are called nitrogenous bases. Together with pyrimidines, another variety of nitrogenous bases, purines help in developing the genetic substances in all living beings. As far as their structure is concerned, the molecules of purines are double-ringed, comprising a five-member ring that is fused to another six-member ring. Each of the two rings of purine comprises two nitrogen atoms or four nitrogen atoms to complete the molecule. There are other atoms too in the molecular structure of purines and they include hydrogen and carbon atoms. Moreover, purine is also called a heterocyclic molecule as the closed rings of the purines each comprise no less than two different varieties of atoms.
In fact, you will find dietary purines in nearly all types of foods. Nevertheless, specific foods contain elevated levels of purines and, hence, it is important that you consume them in moderation in case you are suffering hyperuricemia or gout. Foods containing very high concentration of purines include yeast, anchovies, goose, beef, mackerel, herring, organ meats and mussels. On the other hand, foods that enclose reasonable amounts of purines include asparagus, lentils, beans, spinach, dried peas, poultry, fish, meat and shellfish.