Papaya is a fruit tree found throughout the Philippines, mostly cultivated. The native species grows mostly wild on Mt. Banahaw. Papaya is one of our four “power herbs” having a long history and proof of being a very effective medicinal plant. The leaves, fruits, stem and roots all contain the proteolytic enzyme papain. Exhaustive studies have been done on papain, and it is reported to be a true, soluble, digestive ferment or a mixture of ferments of vegetable origin, its proteolytic action marked in acid, alkaline, and neutral solutions and also in the presence of many chemicals, antiseptics, and therapeutic agents. It has a peculiar softening and disintegrating actions in proteids, and its general proteolytic action is that of a genuine digestive ferment, similar to that of the ferments of animal origin.
It acts in the way rennet does upon milk, and has a pronounced digestive power at a wide range of temperatures. Papain is used effectively as an anthelmintic. The leaves are often employed as a remedy for asthma, and said to also be a heart tonic. The flowers have pectoral properties. The fruit is used in cosmetics for a healthy skin complexion. The green fruit is laxative and diuretic. Studies at the University of Nigeria have revealed that extracts of ripe and unripe papaya fruits and of the seeds are active against gram-positive bacteria. Strong doses are effective against gram-negative bacteria. The substance has protein-like properties.