Theobromine

Theobromine, formerly known as xantheose, is a bitter-tasting alkaloid from the cocoa tree. Its molecular formula is C₇H₈N₄O₂, and its systematic name 3,7-dihydro-3,7-dimethyl-1H-purine-2,6-dione. It can be named as a disubstituted xanthine, thus its name being 3,7-dimethylxanthine. Being a methylxanthine, it is related to caffeine (1,3,7-trimethylxanthine) and theophylline (1,3-dimethylxanthine).

Despite its name, it does not contain bromine: its noun derives from Theobroma, the genus to which the cacao tree belongs. The word Theobroma comes from the Greek roots theo ("god") and broma ("food"), meaning "food of the gods". The suffix -ine is typical of alkaloids and compounds that contain nitrogen.

Chemical properties

It is a slightly soluble compound in water (330 mg/l at 25 °C), which occurs as a white crystalline powder with a characteristic bitter taste. Despite being a colorless compound, commercial samples may have a slight yellowish color due to impurities. It has an effect similar to that of caffeine on the human nervous system, but less potent. It is known to cause mutations in bacteria and simple eukaryotes, but apparently not in complex eukaryotes.

History

Russian chemist Alexander Voskresensky discovered theobromine in 1841 in cocoa beans. The synthesis of it from xanthine was first reported by the German chemist Hermann Emil Fischer in 1882, who twenty years later would win the Nobel Prize in Chemistry for his research on proteins.

Fonts

Theobromine is the main alkaloid found in cocoa and chocolate. Cocoa powder can contain different concentrations of theobromine, from 2% to levels around 10%. Concentrations are normally higher in dark chocolate than in milk chocolate. About 28 grams of milk chocolate contains about 60 milligrams of theobromine, while the same amount of dark chocolate contains about 200 milligrams. This molecule can be found in small amounts in the kola nut (1‒2.5%), guarana, Ilex paraguariensis, and the tea plant. Cocoa beans contain 1% theobromine naturally.

The plant species with the highest concentrations of theobromine are:

• Theobroma cacao
• Theobroma bicolor
• Ilex paraguariensis
• Ilex guayusa
• Camellia sinensis
• Cola acuminata
• Theobroma angustifolium
• Paullinia cupana (Guaraná).
• Arabic buffet

The average concentrations in cocoa products and carob products are those contained in the following table:

Biosynthesis

Theobromine is a purine derivative of xanthosine, a nucleoside. Ribose cleavage and N-methylation produces 7-methylxanthosine, which is a precursor to theobromine, which in turn is a precursor to caffeine.

Therapeutic uses

Theobromine increases urine production. Due to its diuretic effect and its vasodilator ability, theobromine has been used to treat arterial hypertension. The American Journal of Clinical Nutrition notes the historical use of theobromine as a treatment for other circulatory problems, including arteriosclerosis, certain vascular diseases, angina pectoris, and hypertension.

After its discovery at the end of the 19th century, this molecule began to be used in 1916, when it was recommended by the publication Principles of Medical Treatment as a treatment for edema (fluid retention in certain parts of the body) and other problems.

In the human body, theobromine levels halve 6 to 10 hours after consumption.

Theobromine has been used in experiments on birth defects involving mice and rabbits. Subnormal fetal weight was detected in rabbits after theobromine was force-fed, but not after reintroduction of the drug. No birth defects were detected in rats. Possible uses of this compound in future treatments in fields such as cancer prevention have been patented.

Theobromine also appears to be effective against cavities, and has been shown to be more effective than traditional fluoride in some studies. Its advantages include the possibility of swallowing it easily, being able to avoid the warnings of "do not swallow" of current mouthwashes.

Toxicity

Theobromine is found in high concentrations in chocolate. Doses of more than 1000 mg have been used in clinical trials without harmful effects, although they may cause mild stomach upset. To have harmful effects on humans, a large amount of cocoa must be ingested.

However, theobromine is toxic to certain domestic animals, such as dogs and cats in ingested concentrations of more than 80 mg/kg of weight, which causes cardiac arrhythmias and convulsions, and even the death of the animal. Discharges doses in rats have shown irreversible testicular atrophy, but at low doses the same effect has not been noted, nor in other animals such as dogs, mice or hamsters.