Papain is used for inflammation and edema following trauma and surgery, as a digestive aid, for treating parasitic worms, inflammation of the throat and pharynx, herpes zoster symptoms, chronic diarrhea, hayfever, nasal drainage, and psoriasis. Papain is also used as an adjuvant treatment for tumors.
Papain is actually a mixture of the proteolytic enzymes papain, chymopapain A, chymopapain B, and papaya peptidase A isolated from the fruit of Carica papaya. Chymopapain A and B have a similar proteolytic spectrum to papain but are less potent. There is some evidence that a multi-enzyme preparation containing papain can increase the release of reactive oxygen species (ROS) by polymorphonuclear cells (PMNs). ROS are thought to have tumoricidal effects. The multi-enzyme preparation also seems to induce the cytokines tumor necrosis factor (TNF)-alpha, interleukin-1 (IL-1)-beta, and interleukin-6 (IL-6) in a time and dose dependent manner.