Bromelain from Pineapple: Science-Backed Therapeutic Benefits and Mechanisms

The study “Properties and Therapeutic Application of Bromelain: A Review” by Pavan et al. (2012) summarizes published research on bromelain, a proteolytic enzyme mixture derived mainly from pineapple stem. The scientific paper compiles experimental and clinical findings on reported activities linked to inflammation, fibrinolysis, platelet function, and other pathways, and describes proposed modes of action and safety observations across the cited studies.

Bromelain is a group of protein-digesting enzymes obtained from the pineapple plant, known scientifically as Ananas comosus. The authors explain that “bromelain belongs to a group of protein-digesting enzymes obtained commercially from the fruit or stem of pineapple.” Most commercial preparations come from the stem, which is normally a waste byproduct of pineapple farming, making it inexpensive and widely available.

Chemically, bromelain is not a single enzyme. It is a mixture of thiol endopeptidases (enzymes that break peptide bonds within proteins) along with other components such as phosphatases, glucosidases, peroxidases, cellulases, and protease inhibitors. The stem bromelain (EC 3.4.22.32) differs from fruit bromelain (EC 3.4.22.33) in its enzymatic composition.

The scientific paper notes that bromelain has been chemically recognized since 1875 and describes it as a phytomedical compound. It also reports enzymatic activity across a pH range of 5.5 to 8.0, which the authors use to explain why bromelain can function under different test conditions.

This scientific paper is a narrative review that summarizes previously published in vitro (laboratory-based), in vivo (animal and human), and clinical findings on bromelain. The authors also describe common laboratory methods used to characterize bromelain preparations, including sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), isoelectric focusing (IEF), and enzyme activity testing with substrates such as casein and gelatin. Because this is a review, no new experiments were performed; the focus is on compiling and comparing evidence already reported in the literature.

One key concern with enzyme supplements is whether they survive digestion. According to the scientific paper, bromelain can be absorbed in the gastrointestinal tract in an active form. The authors state that “approximately 40% of labeled bromelain is absorbed from the intestine in high molecular form.”

Importantly, bromelain retains its proteolytic (protein-breaking) activity in the blood. It has been found to bind with blood antiproteinases such as alpha-2-macroglobulin and alpha-1-antichymotrypsin. These interactions may help regulate its activity in circulation.

The review also reports that doses as high as 12 g/day have been consumed in published observations “without any major side effects.” The paper further cites stability testing in artificial stomach juice and artificial blood over four hours, which the authors present as supportive evidence that measurable activity can persist under simulated conditions.

The scientific paper also discusses bromelain’s reported effects on platelet aggregation and clot-related laboratory measures. It describes inhibition of platelet aggregation in cited studies and reports that animal work observed prolonged prothrombin time (PT) and activated partial thromboplastin time (APTT) at higher doses, which the authors interpret as evidence of activity in coagulation pathways. The review mentions research contexts that include angina pectoris, transient ischemic attack (TIA), thrombophlebitis, and ischemia-reperfusion injury, but most of the evidence summarized is experimental or limited clinical data rather than large confirmatory trials.

Bromelain has anti-inflammatory and analgesic properties. The review explains that its pain-relieving effects may result from an influence on mediators such as bradykinin.

In one study of 103 patients with knee osteoarthritis, a combination of bromelain, trypsin, and rutin was compared with diclofenac, a nonsteroidal anti-inflammatory drug (NSAID). After six weeks, both groups showed similar reductions in pain and inflammation.

Based on the studies summarized in the review, bromelain is discussed as a supplement ingredient studied for effects related to comfort, swelling, and inflammatory signaling, including in research settings involving osteoarthritis.

Bromelain affects immune cell signaling. Laboratory studies showed it can modulate adhesion molecules on T cells, macrophages, and natural killer cells. It also influences cytokine production, including interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α).

The scientific paper states that bromelain can block the Raf-1/extracellular signal-regulated kinase 2 (ERK-2) pathway, which is involved in T-cell signal transduction. It also reduces activation of CD4+ T cells and expression of CD25.

The review presents these findings as evidence that bromelain can influence immune signaling in laboratory and early clinical research, including changes in cell-surface markers and cytokine release.

The review summarizes animal and laboratory findings in which bromelain was studied for effects on enterotoxin-related intestinal signaling and bacterial adhesion, including models involving Escherichia coli and Vibrio cholerae. It appears to interfere with intestinal secretory signaling pathways, including cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP).

Another mechanism involves antiadhesion effects. The paper describes anti-adhesion effects in which bromelain is reported to proteolytically modify receptor attachment sites, which may reduce bacterial binding in experimental models.

The scientific paper reviews preclinical research that explores bromelain in cancer-related laboratory and animal models. The authors write that bromelain “has the capacity to modify key pathways that support malignancy,” and the cited studies focus mainly on cell lines and animal experiments rather than clinical outcomes in humans.

In the cited preclinical studies, bromelain exposure was associated with higher expression of p53 and Bax and lower activity of signaling proteins such as Akt and extracellular signal-regulated kinase (Erk). The review also discusses the reported downregulation of nuclear factor kappa B (NF-κB) and cyclooxygenase-2 (Cox-2) in specific models.

The review describes animal experiments in which intraperitoneal bromelain administration, under specific study conditions, was associated with reduced tumor measures or regression in selected models, and the authors present this as preliminary evidence rather than confirmed clinical benefit.

The review summarizes trials and reports in which bromelain was studied in postsurgical settings, including outcomes related to swelling, bruising, and comfort. The authors describe these as observed effects in specific study designs, rather than settled clinical guidance.

In burn-related debridement discussions, the review describes topical bromelain preparations containing escharase and reports selective removal of necrotic tissue in cited animal models, while also noting practical drawbacks of surgical approaches such as pain, nonselective removal, anesthesia exposure, and bleeding risk.

The review cites animal studies in which topical bromelain use was associated with measures consistent with faster healing and improved blood perfusion under the tested condition

The scientific paper reports low toxicity in animal testing, including an LD50 greater than 10 g/kg in cited studies. It also summarizes longer-duration animal observations that did not report carcinogenic or teratogenic effects under the described dosing conditions. The review further cites a short human observation using 3000 fibrinolytic activity units per day for ten days, where no significant changes in measured coagulation parameters were reported.

The evidence summarized in this scientific paper suggests bromelain may influence multiple biological pathways, including coagulation-related measures, inflammation-related signaling, immune markers, microbial adhesion, and pathways studied in cancer models.

However, much of the anticancer and mechanistic data comes from laboratory and animal models. More large-scale, randomized human trials are needed to confirm effectiveness and establish standardized dosing.

The authors describe bromelain as a candidate for further research into oral enzyme approaches, and the review highlights oncology as one area of scientific interest, while emphasizing that more research is needed to clarify mechanisms and clinical relevance.

This 2012 scientific paper compiles research on bromelain’s enzyme composition, measured activity across different test conditions, and reported absorption findings. The review summarizes studies that examine inflammation-related markers, fibrinolysis and platelet-related pathways, immune signaling, and topical debridement research, with many results coming from laboratory and animal work, plus limited clinical studies. The paper repeatedly points to the need for stronger human research to clarify mechanisms, dosing, and real-world relevance.