If you have ever cut up a fresh pineapple and noticed how smooth your hands felt afterward, you have experienced the basic action of bromelain. Pineapple (Ananas comosus) is a well-known tropical plant that has been used for centuries for both its medicinal purposes and its food value. Bromelain is a complex chemical found in the aqueous extract of the pineapple and is composed largely of proteolytic enzymes.1 As an individual product, bromelain has been available commercially since 1957. Other components of this substance include glycoproteins, complex carbohydrates, protease inhibitors, and peroxidases.1


Background


Bromelain’s first commercially recognized use was as a meat tenderizer because of its ability to degrade animal proteins. Since then, it has been studied for its potential as an anti-inflammatory, an immune modulator, and even as an anticancer therapy. Bromelain-containing pharmaceutical products are available in other countries both by prescription and over the counter, depending on the intended use. Multiple clinical trials are ongoing in the United States. 


Science 


The most studied and proven action of bromelain is as a proteolytic enzyme. Clinical trials of bromelain-containing products for the nonsurgical debridement of burn eschar have been very favorable. This procedure, long known for being horribly painful, is nonetheless essential for proper healing of severe burns. Because deep and full-thickness burns routinely require performing this painful procedure multiple times during the healing process, skin grafting is also commonly needed for adequate wound coverage. Skin grafting then not only compounds the cosmetic damage but also adds more pain and discomfort. 


Products containing bromelain are being studied for their potential role in this process, with some very promising results. One leading bromelain compound has been found to reduce healthy skin tissue by up to 50%, while also reducing the number of surgical procedures required by more than 75%.2 Overall recovery rates average 85%, with 70% of these patients able to avoid skin grafting completely.2 In one prospective noncomparative trial using a bromelain-derived debriding agent in 130 patients with 332 second- and third-degree burns, wound debridement was accomplished in more than 75% of cases with 1 to 3 applications.2

There is also interest in bromelain for the treatment of osteoarthritis. The proposed mechanism of action is similar to that of other nonsteroidal anti-inflammatory drugs. Taken orally, bromelain acts to block prostaglandin synthesis, thereby reducing the nociceptive perception of pain.3 Another immune-modulatory effect of bromelain is its ability to alter the cellular adhesion of lymphocytes.4,5 In a double-blind randomized study, 103 participants with confirmed osteoarthritis of the knee were treated for 6 weeks with either oral diclofenac or a combination containing bromelain.3 Patient performance was graded by the Lequesne Algofunctional Index and by subjective complaint index.3,6 At the end of the trial, researchers found that the enzymatic compound was as effective as standard diclofenac. 


Bromelain is also considered for its possible antitumoral effects, which are thought to be related to the same pathways as its anti-inflammatory and immune-modulating effects. In vitro studies of bromelain’s action on cultures of cancerous human cell lines have been conducted.7

Safety, interactions


There have been no phase 2 clinical trials in the United States of bromelain, but adverse events reported in human trials to date were usually mild and were resolved by lowering the dose or discontinuing treatment.8

Anyone allergic to pineapple should not receive bromelain therapy. Because of its anti-inflammatory action, bromelain can interact with blood clotting by interfering with the action of fibrin.8

How supplied, dose, cost 


Human clinical trials to ascertain the optimal dose of bromelain, especially in inflammatory arthritis, have shown efficacy beginning at as little as 160 mg/day.9 Although higher doses are used frequently, the incidence of side effects appears to be dose-dependent, with more frequent reports of adverse effects at higher dose ranges. 


Bromelain is available in tablets or capsules, and the cost is as little as $5 per month for the low- to mid-dose ranges.


Summary


The role of bromelain in alternative medicine is certainly intriguing, but it requires larger, better-controlled human clinical trials. Similar to many botanicals, the appeal of “natural” may seem alluring to some. However, the potential for side effects is the same as for a patented medication, and botanicals are not as well-studied. 


As a treatment for serious burns, the use of bromelain-containing products should be considered when used as an aid in the process of debridement. Otherwise, perhaps the pineapple should remain in the Hawaiian drinks with the umbrella. 

Sherril Sego, FNP-C, DNP, is an independent consultant in Kansas City, Mo. 

References

  1. National Institutes of Health National Center for Complementary and Integrative Health. Bromelain. 
https://nccih.nih.gov/health/bromelain. August 2014. 

  2. Rosenberg L, Lapid O, Bogdanov-Berezovsky A, et al. Safety and efficacy of a proteolytic enzyme for enzymatic 
burn debridement: a preliminary report. Burns. 2004;30(8):843-850.

  3. Akhtar NM, Naseer R, Farooqi AZ, et al. 
Oral enzyme combination versus diclofenac in the treatment of osteoarthritis of the knee—a double-blind prospective randomized study. Clin Rheumatol. 2004;23(5):410-415.

  4. Kleef R, Delohery TM, Bovbjerg DH. Selective modulation of cell adhesion molecules on lymphocytes by bromelain protease 5. Pathobiology. 1996;64(6):339-346. 

  5. Müller S, März R, Schmolz M, et al. Placebo-controlled randomized clinical trial on the immunomodulating activities of low- and high-dose bromelain after oral administration—new evidence on the anti-inflammatory mode of action of bromelain. Phytotherapy Res. 2013;27(2):199-204.

  6. Dawson J, Linsell L, Doll H. Assessment of the Lequesne index of severity for osteoarthritis of the hip in an elderly population. Osteoarthritis Cartilage. 2005;13(10):854-860.

  7. Báez R, Lopes MT, Salas CE, Hernández M. In vivo antitumoral activity of stem pineapple (Ananas comosus) bromelain. Planta Med. 2007;73(13):1377-1383. 

  8. Pavan R, Jain S, Singh S, Kumar A. Properties and therapeutic application of bromelain: a review. Biotech Res Int. 2012;2012:976203.

  9. Brien S, Lewith G, Walker A, et al. Bromelain as a treatment for osteoarthritis: a review of clinical studies. Evid Based Complement Alternat Med. 2004;1(3):251-257.



All electronic documents accessed May 5, 2016.