Guarana (pronounced /wrn/), from the Portuguese guaraná, Paullinia cupana (syn. P. crysan, P. sorbilis), is a climbing plant in the maple family, Sapindaceae, native to the Amazon basin and especially common in Brazil. Guarana features large leaves and clusters of flowers, and is best known for its fruit, which is about the size of a coffee berry. As a dietary supplement, guarana is an effective energy booster_it contains about twice the caffeine found in coffee beans (about 24.5% caffeine in guarana seeds compared to 12% for coffee beans).
As with other plants producing caffeine, the high concentration of caffeine is a defensive toxin that repels pathogens from the berry and its seeds.
The guarana fruit's color ranges from brown to red and contains black seeds which are partly covered by white arils. The color contrast when the fruit has been split open has been likened to eyeballs; this has formed the basis of a myth.
Guarana is used in sweetened or carbonated soft drinks and energy shots, an ingredient of herbal tea or contained in capsules. Generally, South America obtains most of its caffeine from guarana