Caffeine can be found mainly in seeds, leaves and fruit of some plants such as coffee beans, guarana, yerba mate, cacao beans, and tea. It is composed of a soft, odorless, slightly bitter tasting white crystalline xanthine alkaloid and a stimulant drug. The most common names for caffeine are 3,7-dihydro-1,3,7-trimethyl-1h-purine-2,6-dione and 1,3,7-trimethylxanthine. Many humans, some 90%, consume more than 300 mg of caffeine every day, making this drug one of the most popular. This drug functions as a central nervous system stimulant, which blocks adenosine receptors in the brain and other organs. To a nerve cell, caffeine appears to look similar to an adenosine that causes fatigue by slowing down nerve cell activity. Caffeine binds to the adenosine receptor, but does not slow down the cells activity. It essentially confuses the nerve cell preventing the cell to not be able to see adenosine anymore because caffeine is taking up all the receptors adenosine binds to. Caffeine also has other effects such as increased heart rate, blood pressure, blood flow to the muscles, along with decreased blood flow to the skin and organs, causing the liver to excrete glucose. The positive effect of alertness and increased focus are short-lived usually wearing off in about five hours. Although there is a strong correlation of dependency to the drug, some studies have shown that there is an association with a lower overall risk of cancer, specifically hepatocellular and endometrial cancer.
Helmenstine, A. (n.d.). What is caffeine and how does it work?. Retrieved from http://chemistry.about.com/od/moleculescompounds/a/caffeine.htm
Sand, R. caffeine. Retrieved from http://www.britannica.com/EBchecked/topic/88304/caffeine
Smith, S. W. (n.d.). Retrieved from http://www.chemistryexplained.com/Bo-Ce/Caffeine.html