About Papaya. Native to the tropics of the Americas, Papaya has been in continuous cultivation for several centuries, principally for its sweet fruit. The leaves are widely used in cooking and contain an enzyme that is useful in tenderizing tough meat. In some parts of South Asia, the young leaves are steamed and eaten like spinach. Papaya was once considered a mystical tree; its leaves were used for medicine and its fruit for food. It remains one of the most popular herbs in Central and South America.