The medicinal qualities of pineapple are recognized in many traditions in South America, China and Southeast Asia. These qualities are attributed to bromelain, a 95%-mixture of proteases. Medicinal qualities include anti-inflammatory, anti-thrombotic, fibrinolytic and anti-cancer functions. Existing evidence derived from clinical observations as well as from mouse- and cell-based models suggests that bromelain acts systemically, affecting multiple cellular and molecular targets. For the past years an ample of studies has been performed demonstrating that bromelain has the capacity to modulate the pathways playing important roles in malignancy establishment and progression. It is now possible suggest that anti-cancer activity of bromelain consists in the direct impact on cancer cells and their microenvironment, as well as in the modulation of immune, inflammatory and haemostatic systems.
The medicinal properties of pineapple have been recognized for a long time. Christopher Columbus discovered the pineapple in Guadeloupe in 1493 and at the beginning of the 17th century, explorers of the New World reported that pineapple:
“admirably recreates and exhilarates the Spirits and comforts the Heart; it also fortifies the Stomack, cureth queasiness and causeth appetite; it gives present ease to such as are troubled with the Stone or stoppage of Urine; nay it destroys the force of Poyson. If the Fruit is not procurable the root will have the same Effects”
After its discovery, the pineapple spread from South America to Asia, where it became a food crop and entered into traditional medicinal pharmacopoeia. In China, the pineapple was used to maintain a healthy spleen, relieve thirst, reduce swelling and remove “wind-wetness evil”. Pineapple-based preparations were used to treat various health complications. For example, indigestion with vomiting and swollen stomach could be treated by eating 250 grams of peeled pineapple twice daily; low blood pressure with dizziness; lack of strength in hands and feet could be helped by stir-frying 250 grams of peeled and sliced pineapple with 60 grams of chicken, some salt and pepper; weakness with fever and thirst is alleviated by the juice of 250 grams of peeled pineapple and one cup of cool boiled water with a pinch of salt that should be drunk twice a day. Avoidance of pineapple is recommended to those with allergies, eczema and boils.
The young pineapple fruit was claimed by the indigenous populations around S.E. Asia to cause foetus abortion when consumed in early pregnancy and aid menstrual flow. In Malaysian villages, the juice from “Hana” fruit (ornamental pineapple plant) is used to treat various cancers.
The medicinal properties of pineapple are attributed to bromelain, an aqueous extract that contains a complex mixture of proteases and non-protease components. Proteases, however, constitute the major components of bromelain (95%) and are considered to be the main active ingredient.
Bromelain is known for many properties, among which are anti-inflammatory, anti-thrombotic, fibrinolytic and anti-edematous. The anti-cancer activities of bromelain are suggested by its traditional usage in countries of S.E. Asia as well as by anecdotal clinical evidence. Thus, French clinical studies performed in 1970s reported bromelain-induced improvement in conditions of cancer patients with ovarian and breast cancers. However, not all concentrations of bromelain are found to be effective. Higher doses (more than 1g per day of active bromelain) were found to be more efficient than lower ones.
There are many indications in scientific publications that bromelain can serve as prophylactics as well as adjuvant therapy for chronic inflammation-based diseases – cancer being one of them. Existing evidence derived from experiments on mice, isolated lines of cancer cells, as well as blood samples from healthy and cancer-affected individuals suggests that bromelain acts systemically, affecting many cellular and molecular targets. Thus, the cancer-inhibitory activity of bromelain will be, among others, the result of the effects on cancer cells, the immune and inflammatory mediators, tumour micro-environment and the blood coagulation system.
Here are some examples of bromelain targets and effects that could contribute to cancer control:
- cancer cells: bromelain can inhibit cancer cells’ viability and reduce their metastatic potential;
- regulators of inflammation: bromelain has the potential to inhibit intracellular regulators of inflammatory genes, among which are NF-kB, Cox2 and PGE2; bromelain can regulate the expression of the potent soluble mediators of immunity and inflammation that are secreted by immune, such as interferon gamma (IFNg), tumor necrosis factor alpha (TNFa), interleukins 1 and 6 (IL-IL-g); depending on the micro-environment, these regulators can act either to suppress cancer cells or to provoke inflammatory response;
- immunosuppressors: bromelain has the potential to reduce elevated levels of one of the key soluble immunosuppressors that was found to be over-produced in conditions of cancer, transforming growth factor beta (TGFb); reduction of TGFb has the potential to reactivate the immune system that is found to be suppressed during cancer;
- cellular components of immune system: bromelain can activate the cells of the immune system, such as neutrophils and lymphocytes; the activity of these cells can be directed against tumour cells.
- platelets: bromelain suppresses activation and aggregation of platelets that might interfere with the platelet-mediated cancer growth and progression as well as prevent generation of tumour-platelet aggregates, thus exposing cancer cells to the immune system.
- fibrin: bromelain can reduce amount of fibrin in blood thus reduce blood coagulation capacities and the risk of thrombus formation.
In conclusion, the systemic effect of bromelain suggests the support of homeostasis and offers the possibility of a cancer prophylactic as well as adjuvant cancer therapy. There are many indications of this view in scientific publications. However, wide acceptance of bromelain-based therapy will require more laboratory-based research in order to understand the molecular mechanisms of its activity as well as properly set-up patient-based clinical studies.